MATERIAL SCIENCE
GROUP PROJECT
Material Selection
Lecturer: Mr. V. Buchanan
Group Members:
• Shannon Thompson
ID#: 1905339
• Emorni White
ID#: 2005398
• Kah-J Moss-Solomon
ID#: 1901006
• Jaden Green
ID#: 1802371
• Dominique Dawkins
ID#: 1800693
Material Selection
Material Science
Group Assignment
Table of Contents
Objective ........................................................................................................................................ 4
Team Contribution ....................................................................................................................... 4
Format............................................................................................................................................ 4
Laptop Touch Screen .................................................................................................................... 5
Definition .................................................................................................................................... 5
History ........................................................................................................................................ 5
Uses of touchscreen laptops ...................................................................................................... 6
Materials .................................................................................................................................... 7
Manufacturing process ............................................................................................................. 7
Property- Control Methods ...................................................................................................... 9
Performance Criteria .............................................................................................................. 10
Razor Blades ................................................................................................................................ 11
Definition .................................................................................................................................. 11
History of The Razor Blade .................................................................................................... 11
Uses of Razor Blades ............................................................................................................... 12
Materials .................................................................................................................................. 12
Manufacturing Process ........................................................................................................... 13
Property-Control Methods ..................................................................................................... 14
Performance Criteria .............................................................................................................. 15
Air Bags........................................................................................................................................ 16
Description ............................................................................................................................... 16
Properties ................................................................................................................................. 16
Working principle of the air bag ........................................................................................... 17
Components ............................................................................................................................. 17
Manufacturing Process ........................................................................................................... 18
Contact Lens ................................................................................................................................ 19
Description ............................................................................................................................... 19
Materials .................................................................................................................................. 19
Manufacturing process ........................................................................................................... 19
Properties ................................................................................................................................. 20
Chemical Structure of Contact lenses ................................................................................... 20
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Material Selection
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Group Assignment
Flywheel ....................................................................................................................................... 21
Description and Use ................................................................................................................ 21
Material Selection and Properties ......................................................................................... 21
Manufacturing Process ........................................................................................................... 22
Performance Criteria .............................................................................................................. 22
Property Control Methods ..................................................................................................... 23
Golf Club Head ........................................................................................................................... 24
Overview .................................................................................................................................. 24
What is a golf club head?........................................................................................................ 24
Purpose of each part. .............................................................................................................. 25
The performance criteria and control. .................................................................................. 25
Why should these performance criteria be noted when creating a golf club head? ...... 25
The materials use to make the golf club head. ...................................................................... 25
The manufacturing processes ................................................................................................. 28
Step to step process to manufacture a golf club head. ..................................................... 28
Golf ball........................................................................................................................................ 33
Overview .................................................................................................................................. 33
What is a golf ball? .................................................................................................................. 33
Types of golf balls. ................................................................................................................... 34
The performance criteria and control. .................................................................................. 34
Why should these performance criteria be noted when creating a golf ball? ................ 34
The materials use to make the golf ball. ................................................................................ 35
The manufacturing processes. ................................................................................................ 35
Drying and Packaging............................................................................................................. 36
$1 Coin ......................................................................................................................................... 38
Application of Coins ................................................................................................................ 38
Performance Criteria .............................................................................................................. 38
Types of materials used........................................................................................................... 39
Manufacturing Processes: ...................................................................................................... 41
Property Control Method ....................................................................................................... 43
Airplane Wings............................................................................................................................ 44
Definition .................................................................................................................................. 45
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Description ............................................................................................................................... 45
Application of wings ................................................................................................................ 46
Performance Criteria .............................................................................................................. 46
Mechanical Properties ............................................................................................................ 46
Chemical Properties ................................................................................................................ 47
The type of materials used to make airplane wings: ............................................................ 48
Manufacturing Properties ...................................................................................................... 49
Property-control methods: ..................................................................................................... 50
Bulletproof Vest .......................................................................................................................... 51
Description and application ................................................................................................... 51
Materials .................................................................................................................................. 52
Manufacturing process ........................................................................................................... 53
Performance Criteria .............................................................................................................. 54
Property Control Method ....................................................................................................... 54
Cutlery Parts ............................................................................................................................... 55
Description and application ................................................................................................... 55
Materials .................................................................................................................................. 55
Manufacturing Process ........................................................................................................... 56
Performance Criteria .............................................................................................................. 57
Property control method ........................................................................................................ 58
References .................................................................................................................................... 59
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Material Selection
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Group Assignment
Objective
This project has been a colossal amount of researching which resulted in an expansion of
knowledge. The sole objective of this project was to apply what was taught in Material Science
class to select 11 products (5 of these products were completely new to the researchers) and
expound on several different areas.
Team Contribution
As a group, our individual contributions to the making of this assignment is as follows:
•
•
•
•
•
Shannon Thompson: Razor blades flywheel (partial) and laptop touch screen. Proofread,
edit, and format
Emorni White: Golf club head and golf balls
Jaden: $1 coin and Airplane wings
Kah-J Moss- Solomon: cutlery parts and bulletproof vest
Dominique Dawkins: Contact lens, airbags, and flywheel (partial)
Format
This assignment has 6 known objects and 5 unknowns. Please see the below table which
illustrates which item falls under which heading:
KNOWN
Razor Blade
Golf Club
$1 Coins
Cutlery Parts
Contact Lens
Flywheel
UNKNOWN
Laptop touch Screen
Golf Balls
Airplane Wings
Bulletproof Vests
Airbags
-
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Group Assignment
Laptop Touch Screen
Source: (Woodford, 2019)
Definition
It is hard to believe that just a few decades ago, touchscreen technology could only be found in
science fiction books and film. These days, it is almost unfathomable how we once got through
our daily tasks without a trusty tablet or smartphone nearby (Ion, 2013). A touchscreen in is just
an ordinary LCD device that has an additional human-interface device (HID) that allows users to
touch the screen to further interact with the RasPi in accordance with an underlying
control/display program (Norris, 2016). Essentially, a laptop with touchscreen can be described
as a regular laptop with the keyboard attached but the screen is enabled for touch (DelCor Staff,
2016).
History
The first touchscreen was invented in 1965 by Eric A. Johnson who worked at the Royal Radar
Establishment in Malvern, England. His first article, "Touch display—a novel input/output
device for computers" describes his work and features a diagram of the design. The invention is
known as a capacitive touchscreen, which uses an insulator, in this case glass, coated with a
transparent conductor, like indium tin oxide. The user's finger also acts as a conductor and
disrupts the capacitance of the conducting layer. In more simple terms, touching the screen
causes a change in the electric charge that the computer detects. Johnson patented his design in
1966, improved it in 1968, and wrote another article in the same year. At some point, it was
adopted by British air traffic controllers and was used into the 1990s (Displays2Go, 2018).
Although capacitive touchscreens were designed first, they were eclipsed in the early years of
touch by resistive touchscreens. American inventor Dr. G. Samuel Hurst developed resistive
touchscreens almost accidentally. Hurst and the research team had been working at the
University of Kentucky. The university tried to file a patent on his behalf to protect this
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accidental invention from duplication, but its scientific origins made it seem like it was not that
applicable outside the laboratory. Hurst, however, had other ideas. "I thought it might be useful
for other things," he said in the article. In 1970, after he returned to work at the Oak Ridge
National Laboratory (ORNL), Hurst began an after-hours experiment. In his basement, Hurst and
nine friends from various other areas of expertise set out to refine what had been accidentally
invented. The group called its fledgling venture "Elographics," and the team discovered that a
touchscreen on a computer monitor made for an excellent method of interaction. All the screen
needed was a conductive cover sheet to make contact with the sheet that contained the X- and Yaxis. Pressure on the cover sheet allowed voltage to flow between the X wires and the Y wires,
which could be measured to indicate coordinates. This discovery helped found what we today
refer to as resistive touch technology (because it responds purely to pressure rather than electrical
conductivity, working with both a stylus and a finger). As a class of technology, resistive
touchscreens tend to be very affordable to produce. Most devices and machines using this touch
technology can be found in restaurants, factories, and hospitals because they are durable enough
for these environments. Smartphone manufacturers have also used resistive touchscreens in the
past, though their presence in the mobile space today tends to be confined to lower-end phones
(Ion, 2013).
Tech companies were starting to take notice of this new way to control computers. HewlettPackard was the first to release a product that put touchscreens in the hands of everyday users.
HP made a name for itself in the 1960s and 70s for creating smaller and smaller computers to the
point where it had made one of the first machines to be called a "personal computer", the 9100A.
In 1983, Hewlett-Packard released the HP-150, also known as the HP Touchscreen. The included
device used a new system for touch input, featuring a grid of infrared emitters and detectors in
the monitor's bezel. When the infrared beams were interrupted, the HP-150 could locate where
the user was touching the screen. However, the system had its faults: dust would get into the
infrared holes and require vacuuming. The design was not ergonomic either, users would
complain of muscle fatigue, or "Gorilla Arm" from keeping their arm outstretched and
unsupported for long periods of time. This first foray into a consumer touchscreen device was
not incredibly popular. When the HP Touchscreen II released in 1984, the touch screen was
optional, and rarely added. Meanwhile, other touch technologies were being developed. Myron
Krueger, an American computer artist developed the Video Place, a screen that could track a
user's silhouette and movements. Multi-touch was also proven in 1982 at the University of
Toronto by Nimish Mehta. This design also used a camera to identify where the user was
touching the screen. The first multi-touch overlay was developed in 1984 by Bob Boie of Bell
Labs, creating a true capacitive screen that could detect multiple points of contact (Displays2Go,
2018).
Uses of touchscreen laptops
Touchscreens really are everywhere. Homes, cars, restaurants, stores, planes, wherever—they fill
our lives in spaces public and private (Ion, 2013). For people who use laptops with touchscreen
displays, they mention that the touchscreen feature makes them more productive since it helps
them accomplish tasks faster. Touchscreen models are very feasible for specific tasks, like taking
notes and doing creative work from sketching to drawing. Navigating the display is made faster
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Group Assignment
and more convenient just by using one finger or more. In addition, touchscreen models are
aesthetically pleasing and have excellent colour accuracy and brightness, too. It is recommended
for people who often work with colour. If you are a student or a creative, maybe touchscreen
models are more your speed since it makes note-taking and arty activities faster to accomplish
(Haden, 2020).
Materials
Laptop touchscreens can be made of glass or plastic. Acting like a keyboard, they use 2 layers of
material. The first layer interacts with the second when pressed to form a circuit and send a
command. Some touchscreens can only interact with point at a time. One example is a resistive
touchscreen often made of polyester and bound to conductive glass separated by an insulated
membrane. The circuit is connected when the polyester is pressed down on the glass. In another
example a capacity screen has both layers of the screen conduct electricity. By touching the
screen, the electrical field is altered. On advantage of these screens is that they can be pressed in
more than one place and function. Infrared touch screens utilize a grid pattern of LED lights and
a light detector photocell arranged on opposite sides of the screen. When touching the screen
these lights are interrupted and a microchip calculates where this interruption is and creates the
command based on the lights connected to that section of the screen. Surface acoustic wave
using ultrasonic sounds that are generated at the edges of the screen which reflect across the
screen back and forth. When touched the sound beam is interrupted and absorbed. The microchip
in the screen figures out where on the screen is touched and initiates the command (Woodford,
2019).
Manufacturing process
The following is an excerpt of how touchscreens are made for the book Raspberry Pi®
Electronics Projects for the Evil Genius (Norris, 2016) (https://www-accessengineeringlibrarycom.ezproxy.utech.edu.jm/content/book/9781259640582/chapter/chapter2)
•
Resistive Touchscreens:
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Material Selection
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Group Assignment
The touchscreen is made up of six layers, as you can see from the figure. The top layer is a
protective flexible, clear-plastic layer, which is the one you press your fingertip or plastic stylus
against. Immediately underneath the plastic overlay is the ITO X-layer. ITO is an acronym for
"indium-tin-oxide," which is a mildly conductive metal alloy. The ITO layer is extremely thin
and transparent. It can be thought of as a two-dimensional resistor that is used to detect the Xaxis touchpoint coordinate. I will discuss how this is accomplished after I introduce the
remaining layers. Next follows a layer of nonconductive transparent dots that provide an air gap
between the ITO X-layer and the ITO Y-layer, which is located immediately under the dot layer.
The ITO Y-layer is made up of the same material as the X-layer, and it is used to detect the Yaxis touchpoint coordinate. A thin glass layer lies directly under the ITO Y-layer, and it provides
a stable platform for all the layers above it. Finally, an LCD display with a backlight is
positioned under all the layers just discussed. It should be noted that the LCD used in
touchscreen design should be very quiet from an electrical noise perspective to minimize
potential interference with the touch sensor elements.
There are three flexible metalized traces printed on the X-axis ITO layer; two are vertical bus
lines, and the third is a horizontal sense line. The left-hand bus line has +5 VDC applied to it
from the touchscreen controller chip. The right-hand bus line is at ground or 0-VDC potential.
These bus lines will cause a distributed current flow across the ITO layer because the ITO alloy
acts more like a resistor than a perfect conductor.
•
Capacitive touchscreens
The capacitive touchscreen functions in a somewhat similar fashion to the resistive version, but it
uses a somewhat different layer structure.
This touchscreen uses a glass top layer, which provides 100 percent clarity. The next layer is an
ITO layer consisting of an array of closely spaced dots, which are one part of the capacitive
sensing scheme. Following this layer is a pressure-sensitive adhesive (PSA) that closely couples
the two ITO layers while providing an insulator between them. The next layer consists of more
ITO dots, like the layer above. The two ITO layers make up a fine grid of micro capacitors, with
the PSA layer acting as a dielectric. The display LCD is placed beneath the second ITO layer,
completing the touchscreen assembly.
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Material Selection
Material Science
Group Assignment
The essence of touch sensing is that when a fingertip or appropriate stylus touches the top glass
cover, it will slightly affect the capacitance of one or more of the micro capacitors beneath the
touchpoint. The touch effect is not much, generally about a 4 to 5 percent change, but the
touchscreen controller can detect this small change in capacitance. The touchscreen controller
also uses individual wires to connect to each row and column of the micro capacitor array, and it
will poll or sense these wires to detect the capacitors that have changed value as a result of the
touch.
Property- Control Methods
• Resistive Touchscreens
The ITO layer will deform when a fingertip or a plastic stylus is pressed onto the outermost poly
layer. This deformation causes a slight disruption in current flow, which can be detected by the
sense line as a voltage between 0 and 5 V. The deformed ITO layer acts as a virtual
potentiometer in which the sense line is the virtual center tap (Norris, 2016).
The sense line is connected to an analog-to-digital converter (ADC) within the touchscreen
controller, and the digital equivalent to the sensed voltage is then sent to the RasPi for further
processing. The ADC typically has either 10 or 12 bits of resolution depending on the size and
resolution of the touchscreen sensor. However, you do not have to be concerned with the actual
ADC bit resolution because that is already figured into the RasPi driver software. The Y-axis is
essentially identical to the X-axis except that all the bus and sense lines are oriented 90° to those
of the X-axis. The touchscreen controller will energize the Y-axis bus lines only milliseconds
after completing the X-axis coordinate read operation. Obviously, the touchpoint is the same for
the Y-axis as it is for the X-axis because the Y-axis ITO layer is directly under the X-axis,
separated by the insulating dot layer (Norris, 2016).
The touchscreen just described is also referred to as a four-wire touchscreen, as the number
refers to the interconnecting wires between the ITO layers and the controller. Five- and eightwire resistive touchscreens are also available, as they offer improved accuracy and sensitivity
(Norris, 2016).
•
Capacitive Touchscreen
As you can imagine, this sensing scheme is quite stable and requires little to no recalibration
once it is set up. There is, however, one issue regarding coordinate resolution. The problem is
that placing a fingertip on the top glass screen will affect more than one or two micro capacitors,
thus hindering accurate sensing of the desired touchpoint (Norris, 2016).
The solution to this problem is to employ a technique known as projected capacitive sensing.
This technique uses all the changed values of the micro capacitors in and around the touchpoint
to determine the center of gravity of the touchpoint by a process of interpolation. Note that no
physical changes were done to the ITO dots to implement this technique. It is all accomplished
by software residing in the touchscreen controller (Norris, 2016).
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Performance Criteria
Functionality: Interactive screens enhance the user’s experience by adding in tactile functionality
and allowing the user to have more control over their device (Sirois, 2018). The touchscreen
feature on laptops was developed primarily to make navigation easier and more convenient.
Users get to perform plenty of tasks using this feature compared to trackpads and mouse devices.
Launching applications and shifting between them is also made simpler (Haden, 2020).
Appearance: Touchscreen laptops often come with excellent brightness and better colour
accuracy, vibrancy and reproduction compared to standard ones. Most models with this feature
also have displays with higher resolution. Touchscreen displays are glossy so they can respond to
touch better than matte ones. Due to their excellent colour accuracy and brightness, lots of users
who often work with colour choose touchscreen models (Haden, 2020).
Insulator: Capacitive screens relies on electrical capacitance. In order for the consumer to not be
shocked each time the device is used and to prevent wear on the conductive layer, an insulator
(such as glass) is placed between two conductive layers (Poor, 2017).
Ease of maintenance: A common problem associated with traditional laptops is keyboard failure.
When crumbs, dirt or other debris falls into the laptop’s keyboard, it may prevent the keys from
working properly. Since touchscreen laptops do not have keyboard, however, this is not an issue.
With a touchscreen laptop, you can rest assured knowing that dirt or debris won’t affect its
ability to register your input commands (Nelson-Miller Inc, 2019).
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Material Selection
Material Science
Group Assignment
Razor Blades
Source: (Cadence Blades, n.d.)
Definition
When a person refers to razors, the first thing to come to mind is the item used to shave
unwanted hairs from the body. While that is true, a more generalized definition according to the
Cambridge Dictionary is that a razor blade is a thin flat piece of metal with
a sharp edge for cutting (Cambridge Dictionary). For this experiment we will focus mainly on
safety razors. A safety razor is a device used to remove hair from areas of the body where it is
undesirable such as the face for men and the legs and underarm regions for women (How
Products Are Made, n.d.). As safety razor usage has increased and become more popular, the
available models and types of razor blades have also significantly increased (Fendrihan, 2014).
History of The Razor Blade
The razor took a long time to evolve to its present multifaceted use (Dibacco, 1992). During the
last Ice Age, facial hair was considered dangerous since wet facial hair could freeze and cause
frostbite. Early humans (according to cave painting and implements found) are believed to have
been grooming their facial hair using seashells (like a pair of tweezers). This trend later
developed to use of sharp and fine obsidian flakes and shards from clams and oysters.
Subsequently, the agricultural revolution and metal age allowed for access to metalworking,
tools for farming, and metal blades for shaving. Although unsafe, men and women were able to
benefit significantly from the advent of these ages (Silva, 2019).
The ancient Egyptians began the custom of shaving their beards and heads, which was eventually
adopted by the Greeks and Romans around 330 B.C. This practice was advantageous for soldiers
because it prevented enemies from grasping their hair in hand-to-hand combat. The unshaven,
unkempt tribes they fought became known as barbarians, meaning the unbarbered (How
Products Are Made, n.d.). In the 18th century, razor blades were finally made thin and sharp
pieces of metal. Till this time, everybody presumed shaving could only be done by professionals
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Material Selection
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Group Assignment
and would employ daily barbers for the facial and personal grooming. French inventor JeanJacques Perret invented a safety razor by adding a wood guard to a regular blade thereby
allowing men and women to shave without the help of a barber. The modern Sheffield razor is an
evolved design version of this razor with a rotating guard. In 1880 the Kampfe brothers patented
a design for the world’s first safety razors which had a wire guard along the edge and lathercatching head (Silva, 2019).
Although numerous inventors tried to devise ways to keep the razor’s sharp edge from cutting
the skin, it was King Camp Gillette, a Wisconsin-born salesman, who persevered in the quest for
a safety appliance. But it was a long way from Gillette’s first efforts in 1895 to actual marketing
of his gizmo in 1903. The problem was not the razor and its protective housing, which allowed
only a small part of the double-edged blade to be exposed, thereby reducing the likelihood of
cutting the skin. Rather, the challenge was to fashion a steel blade that was very thin, strong,
inexpensive, --and safe. Still, the first year of marketing was a bummer for Gillette, who sold
only 51 razors, at $5 each, and 168 blades. Three years later, however, word about Gillette’s
bloodless means of shaving had spread, and about 300,000 razors and twice as many blades had
been sold. For two decades Gillette, living up to his name, was king of the razor industry
(Dibacco, 1992).
Gillette manufactured carbon steel blades until 1960. These were rapidly rusting and required the
user to change the blades frequently. In 1965, the British company Wilkinson Sword began
selling stainless steel blades, which did not rust and could be used several times until they were
blind. Wilkinson quickly dominated the British and European markets, and Gillette was forced to
switch its production lines to stainless steel to compete. Today, almost all blades are stainless
steel. Carbon steel blade is still available; Its modern version will not rust if it is washed in
alcohol after each shave. Because Gillette holds the patent for stainless blades but did not act on
them, the company was accused of exploiting customers by forcing them to buy rust-prone
blades (Silva, 2019).
Uses of Razor Blades
Razors and razor blades have many uses, from personal hygiene to cutting a sewing stitch to
opening a cardboard box sealed with heavy-duty tape (Dibacco, 1992). Common applications of
razor blades would include to use it to deburr PVC conduit (Zoellner, 2017). If the PVC is cut
and the edges are rough it can damage the insulation of the wires. To smoothen it out, running
the blade along the inside of the conduit will do the trick. Other use of razor blades in the
construction industry is where it is used to remove small imperfections from wood finishes
(Pawlak, 2015) and scraping away paint overspray (Zoellner, 2017). Then there are razors that
are used for shaving. Those types include disposable razors, electric razors, safety razors and
many more (Centeno, n.d.). Razors have always been a necessity and are often called into service
for a variety of tasks around the shop other than shaving (Pawlak, 2015).
Materials
Depending on which company that creates them, razor blades are made up of different
compounds but all leading up to a form of steel alloy. Razor blades are periodically exposed to
high levels of moisture and therefore must be made from a special corrosion resistant steel alloy
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Group Assignment
(How Products Are Made, n.d.). So, the steel to be used must be a grade that is hard and
malleable; allowing the blade to hold its shape and to be processed, respectively. The preferred
type of steel is called carbide steel because it is made using a tungsten-carbon compound (How
Products Are Made, n.d.). One patented combination of elements used in stainless steel blade
construction includes carbon (0.45-0.55%), silicon (0.4-1%); manganese (0.5-1.0%); chromium
(12-14%) and molybdenum (1.0-1.6%); with the remainder being iron (How Products Are Made,
n.d.).
The plastic portions of a safety razor include the handle and blade cartridge, or portions thereof,
depending on the razor design. These parts are typically molded from several different plastic
resins including polystyrene, polypropylene, and phenylene oxide-based resins as well as
elastomeric compounds. These resins are taken in pellet form and are melted and molded into the
razor components through a combination of extrusion and injection molding techniques. For
example, in making the handle for their advanced shaving systems, Gillette uses a coextrusion
process which simultaneously molds an elastomer molded over polypropylene to create a surface
that is easy to grip (How Products Are Made, n.d.).
Manufacturing Process
The following explains the process in which the razor blade and its plastic housing are made.
Source: (How Products Are Made, n.d.)
•
•
•
•
1. Cutting Blade Formation
Blade manufacturing processes involve mixing and melting of the components in the
steel. This mixture undergoes a process known as annealing, which makes the blades
stronger. The steel is heated to temperatures of 1,967-2,048°F (1,075-1,120°C), then
quenched in water to a temperature between -76- -112° F (-60- -80° C) to harden it. The
next step is to temper the steel at a temperature of (482-752°F (250- 400°C).
The blades are then die stamped at a rate of 800-1,200 strokes a minute to form the
appropriate cutting-edge shape. The actual cutting edge of modern cartridge style razor
blade is deceptively small. The entire cutting surface is only about 1.5 in (3.81cm) wide
by 1 mm deep. This is compared to traditional razor blades which are almost 20 times
wider and several times thicker. This design creates efficiencies in manufacturing by
allowing the creation of a durable cutting surface using very little metal. Because the
blade is so small, a special support structure is required to hold it inside the cartridge.
2. Support Member Formation
At a separate workstation, another sheet of metal passes through a die and cutter device to
form a series of L-shaped support members. These support members are formed in a line
with two edge runners connected to each side.
The row of supports, still connected to the edge runners is rolled onto a coil and
transported to the next station. There the support pieces are severed from the edge
runners which are collected in a waste bin. The support members are dropped into a
funnel-like device equipped with a vibrating unit which deposits individual support
members onto a conveyor belt. The belt transfers the members in a single file fashion the
third workstation where they are welded onto the cutting blade. The finished blade
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Material Selection
•
•
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Material Science
Group Assignment
assembly is then ready for mounting in the cartridge. Because the entire process is
automated, waste from broken or bent cutting blades and support members is minimized.
3. Plastic Component Molding
Concurrent with the blade-making operations, the plastic components are molded and
readied for assembly. The plastic resins are mixed with the plasticizers, colorants,
antioxidants, stabilizers, and fillers. The powders are mixed and melted in a special
heated screw feeder. The resultant mixture is cut into pellets which can be used in
subsequent molding operations.
Plastic razor parts are typically extrusion molded. In this process, molten plastic is shaped
by being forced through the opening of a die. The parts can also be manufactured by
injection molding, where plastic resin and other additives are mixed, melted, and injected
into a two-piece mold under pressure. After the plastic has cooled, the mold is opened,
and the plastic parts are ejected. Major manufacturers have extremely efficient molding
operations with cycle times for molded plastic parts routinely below 10 seconds. These
processes are so efficient that the thermoplastic runners and other scrap from the molding
process are reground, remelted, and reused.
4. Assembly of Components
The molded plastic components are fed to various workstations where the blade assembly
is inserted into the cartridge. The work surfaces in these stations are equipped with
vacuum lines to orient and hold the small blade parts in place during transport and
insertion. Spring loaded arms push the blades into place and secure them in the cartridge
slots. The finished cartridge may be attached to the razor handle during subsequent
operations or they may be packaged separately. This step may include insertion of springs
and other parts in the handle to allow ejection of the cartridge.
Property-Control Methods
Polished razor blades are separated into single pieces at this stage for the first time, then, they are
bunched together and skewered. The back of the blade has the typical luster of stainless steel, but
on the contrary, the sharp blade tip does not reflect the light and appears to be black. If the blade
tips reflect light, it means that they do not have enough sharp angle and that they are defective
products. Each razor blade is visually inspected in this way (Kai Industries Co. Ltd, n.d.).
At the packaging stage, various sensors, put on the assembling machine and on the conveyor,
check abnormalities, position of the resin parts, assembly precision and many other check items.
In this way, high quality razors are completed (Kai Industries Co. Ltd, n.d.).
All finished razor components must conform to tight specifications before they are released. For
example, blades must meet a designated hardness rating and contain a certain amount of steel.
Gillette blades must meet a standard knows as Vickers hardness of at least 620 and a carbide
density of 10-45 particles per 100 square microns to avoid rejection. The equipment itself
operates so precisely that Gillette measures its reject rate in parts per million. Similarly, molded
plastic parts are closely inspected by operators with lighted magnifying glasses to check for loose
flashing or rough edges; they alert technicians when problems are discovered. In addition, razor
14
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Group Assignment
components are checked by a computerized vision system which compares a critical dimension
to a reference (How Products Are Made, n.d.).
Performance Criteria
Availability: Razor blades are made from many companies, such as Gillette. They are also
disposable brands as well as brands allowing for the razor to be removed and replaced.
Corrosion resistance: Maximally sharpened blades are coated with hard metal film to make them
difficult to be worn away. This coating has also the purpose to make blade tips difficult to rust
(Kai Industries Co. Ltd, n.d.).
Flexibility: Due to its thin shape, razors can handle an amount of bending. A razor cartridge
including a razor blade having a bent portion can have certain advantages, such as decreased
manufacturing costs and improved rinsability. This allows the user to be able to easily rinse cut
hair and skin particles and other shaving debris from the razor cartridge and especially from
between adjacent razor blades or razor blade structures (United States; The Gillette Company
(Boston, MA, US) Patent No. 20160361828, 2016).
Durability: Blades are additionally coated with fluorine resin, to allow them to move smoothly
across the skin. Then, resin is heated and melted to form a film on the surfaces. This two-layer
coating greatly improves the sharpness and the durability of razors (Kai Industries Co. Ltd, n.d.).
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Material Selection
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Group Assignment
Air Bags
Description
An airbag is a vehicle occupant restraint system using a bag designed to inflate extremely rapidly
then quickly deflate during a collision. It consists of the airbag cushion, a flexible fabric bag,
inflation module and impact sensor. The purpose of an airbag is to help the passenger in the car
reduce their speed in collision without getting injured. An airbag provides a force over time. The
more time the force must act on the passenger to slow them down, the less damage caused to the
passenger.
Properties
High Tensile strength
Good heat stability
High Tear strength
Low Air permeability
Tensile strength is a measurement of the force required to pull something such as rope, wire, or a
structural beam to the point where it breaks. The tensile strength of a material is the maximum
amount of tensile stress that it can take before failure, for example breaking. As a result of breaking
the air bag is pushed out to protect the passenger after impact.
Thermal stability is the stability of a molecule at high temperatures, i.e. a molecule with more
stability has more resistance to decomposition at high temperatures. Thermally stable means it will
not break or disintegrate with change in temperature.
Tear resistance (or tear strength) is a measure of how well a material can withstand the effects of
tearing.
The air permeability of a fabric is a measure of how well it allows the passage of air through it
hence, the air bag requires a low one to reduce damage done to the passenger after impact.
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Working principle of the air bag
For an airbag to be useful as protective device, the bag must deploy and inflate within the stipulated
time. It takes only about 30-60 milliseconds to get activated at the event of collision. Airbags
become energy-absorbing buffers between people and the hard-interior surfaces of vehicles.
Normally air bags are hidden in the hub of the steering wheel or in the dash on the passenger’s
side.
Once the sensor has turned on the electrical circuit, a pallet of sodium azide (NaN3) is ignited,
and a rapid reaction occurs, generating nitrogen gas. This gas fills a nylon or poly amide bag at a
velocity of 150-230 miles per hour. For the air bag to cushion the head for maximum protection,
the air bag must begin to deflate (decrease its interval pressure) by the time the body hits.
Otherwise the high internal pressure of the airbag would create a surface as hard as stone – not the
protective cushion.
Reaction- (I)
2NaN3 = 2Na + 3N2
The sodium by product of this reaction, and the potassium nitrate generate additional N2, which
also helps to fill airbag.
Reaction-(ii)
10Na + 2KNO3 = K2O + 5Na2O + N2
This reaction leaves potassium oxide and sodium oxide to react with the 3-rd compound silicon
dioxide, and forms alkaline silicate (“glass”), which is a safe and stable, unignitable compound.
Reaction-(iii)
K2O + Na2O + SiO2 = Alkaline silicate
NaNO3 is very toxic in nature (0.2 mg/m3 is only allowed in workplace) is been converted to
alkaline silicate. The Na metal, which is explosive in nature, is been converted to alkaline silicate
using KNO3 and SiO2.
Components
Nylon 6,6 is the material of choice for airbags because Nylon offers various advantages in airbag
application compared to other fibres. In general, the Nylon fibre exhibits high specific strength,
abrasion resistance, and toughness or energy-absorption properties. The aging characteristics of
Nylon are also very good (Keshav raj et al., 1996), which is important because airbags typically
need to have a replacement period of at least 15 years (Sun and Barnes, 2010)
Nylon fabric has a greater bi-axial elongation compared to other fabrics due to its lower stiffness.
This is a major advantage because it provides a more uniform bi-axial stress distribution. (Keshav
raj et al., 1996)
Nylon is a synthetic polymer (man-made polymer) made up of repeating units which are linked by
amide bonds. To make the repeating unit or the monomer, molecules with an acid (-COOH) group
on each end are reacted with molecules containing amine (-NH2) groups on each end. The
monomers are then reacted together to form long polymer chains. The resulting Nylon is named
based on the number of carbon atoms donated by the monomers, the diamine first and the diacid
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second. So, for example, Nylon 6,6 refers to the diamine and the diacid donating 6 carbon atoms
each to the polymer chain.
Manufacturing Process
Mostly used raw material for the airbag fabric is nylon 66 yarns in the deniers ranging from 420
to 840. The side impact airbags used 1880 D nylon-6.6. These fabrics are generally woven with
the constriction of:
•
840 X 840 D, 98 X 98 /dm plain weave, 60” width.
•
420 X 420 D, 193 X 193 /dm plain weave, 60” width
Commonly, the airbag made were coated by neoprene, but recently silicon coated, and uncoated
varieties have become popular. Coated airbag is generally preferred for driver seats. The weight
per unit length uncoated one is higher than coated bags, i.e. 244 to 257 Vs 175 g/m2. Usually
Rapier with insertion rate of 400 m/min has been found most suitable for weaving airbags. Since,
it can maintain warp tension with accuracy of 1 CN per warp.
Methods of coating the substrates, comprises of water, continuous emulsion of a curable
elastomeric polymer, and aqueous polyurethane dispersion, and an optional cure agent.
The chemical structure of Nylon 6,6 is (C12H22N2O2)n. it comprises of two monomers
hexamethylene diamine and adipic acid which gives nylon 6.6 its name.
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Material Selection
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Contact Lens
Description
A contact lens is a thin, curved lens placed on the film of tears that covers the surface of your eye.
The lens itself is naturally clear but is often given the slightest tinge of colour to make them easier
for wearers to handle. Today's contact lenses are either hard or soft.
Materials
Soft lenses are made from gel-like, water-containing plastics called hydrogels. These lenses are
very thin and pliable and conform to the front surface of the eye. Introduced in the early 1970s,
hydrogel lenses made contact lens wear much more popular because they typically are immediately
comfortable. The only alternative at the time was hard contact lenses made of PMMA plastic.
Silicone hydrogel lenses are an advanced type of soft contact lenses that are more porous than
regular hydrogel lenses and allow even more oxygen to reach the cornea. Introduced in 2002,
silicone hydrogel contact lenses are now the most popular lenses prescribed in the United States.
Manufacturing process
Soft contacts are made of hydrophilic ("water-loving") plastic polymers called hydrogels. These
materials can absorb water and become soft and pliable without losing their optical qualities.
Soft contacts — including new highly oxygen-permeable varieties called silicone hydrogel lenses
— can be made with either a lathe cutting process or an injection moulding process.
Lathe cutting. In this process, non-hydrated disks (or "buttons") of soft contact lens material are
individually mounted on spinning shafts and are shaped with computer-controlled precision cutting
tools. After the front and back surfaces are shaped with the cutting tool, the lens is then removed
from the lathe and hydrated to soften it. The finished lenses then undergo quality assurance testing.
Injection moulding. In this process, the soft contact lens material is heated to a molten state and
is then injected into computer-designed moulds under pressure. The lenses are then quickly cooled
and removed from the moulds. The edges of the lenses are polished smooth, and the lenses are
hydrated to soften them prior to undergoing quality assurance testing.
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Properties
Some properties are:
•
•
•
Wettability
Coefficient of friction
Modulus
The degree of wetting is determined by a balance between adhesive and cohesive forces acting on
a lens surface. Contact lenses that can sustain complete wetting allow a thick coverage of the tear
film, a smooth recovery of the tear layer after eye closure and good visual acuity.
Wettability is determined by measuring the contact angle, the smaller the contact angle the greater
the wettability. Contact angles can be classified as dynamic or static, advancing or receding. There
are several methods that can be used to determine the contact angle: Wilhelm plate, captive bubble,
and sessile drop.
The property of modulus or "stiffness" is not something we used to think about with hydrogel
lenses. It is relevant for silicone hydrogels as the addition of silicone often results in a lower
amount of water in the lens; the combination and balance of these factors leading to silicone
hydrogel lenses generally having a higher modulus than hydrogel materials.
Modulus is a measure of how a material will deform and strain when put under pressure. Elastic
or Young's modulus (E) is described as the ability of a lens material to align to the ocular surface
and resist deformation under tension.
The coefficient of friction (CoF) refers to how lubricious the surface of the contact lens is. It is
sometimes referred to as lubricity and a lower CoF helps to give lenses a silky, smooth feel. It is
quantitatively measured via micro tribometry. The set-up is designed to mimic on eye- eyelid
interactions.
Chemical Structure of Contact lenses
The first polymer contact lenses became commonly available in the early 1960s and were made
from a polymer called poly (methyl methacrylate) (PMMA). Lenses made of PMMA are called
hard lenses. PMMA is still used in Plexiglas and Lucite, as well as for things like aquariums and
ice hockey ring barriers.
A different polymer was then made, poly (hydroxyethyl methacrylate) to create soft, flexible
hydrogel lenses, which had the added advantage of being permeable to oxygen. These lenses were
more comfortable, and as such could be worn for longer.
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Material Selection
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Flywheel
Description and Use
A flywheel is a heavy wheel that is part of some engines. It regulates the engine's rotation,
making it operate at a steady speed. A flywheel stores energy as it spins inside a casing. A
flywheel that keeps an engine turning relies on its momentum to keep going, it is used to store
rotational energy. Flywheels have an inertia called the moment of inertia and thus resist changes
in rotational speed. For example, flywheels are used in reciprocating engines because the energy
source, torque from the engine, is intermittent.
Flywheels used in car engines are made of cast or nodular iron, steel or aluminium. Flywheels
made from high-strength steel or composites have been proposed for use in vehicle energy
storage and braking systems. If the hoop stress surpasses the tensile strength of the material, the
flywheel will break apart.
Material Selection and Properties
For the fabrication of flywheel as per the priority five topmost material is Carbon steel 10657,
Alloy steel AISI 43408, Maraging steel 18ni9, Alloy steel AISI E931010 and Stainless steel11.
As per the decision makers, the following properties were chosen, they are Density, hardness,
young’s modulus, bulk modulus, and Poisson’s ratio.
Maraging steels are carbon free iron-nickel alloys with additions of cobalt, molybdenum,
titanium and aluminium. The term maraging is derived from the strengthening mechanism,
which is transforming the alloy to martensite with subsequent age hardening,
Young's modulus is a measure of the ability of a material to withstand changes in length when
under lengthwise tension or compression. Sometimes referred to as the modulus of elasticity,
Young's modulus is equal to the longitudinal stress divided by the strain.
Bulk’s Modulus is the relative change in the volume of a body produced by a unit compressive
or tensile stress acting uniformly over its surface.
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Poisson’s Ratio is the ratio of the proportional decrease in a lateral measurement to the
proportional increase in length in a sample of material that is elastically stretched.
Manufacturing Process
A flywheel is used primarily in manual transmissions. It is attached to the engine crankshaft and
holds the ring-gear that is used to crank the engine. The wheel connects directly to the clutch,
stores energy to move the vehicle from inertia, and provides a friction surface for the clutch to
attach to. Because of this, these parts are usually cast, and are thick and heavy, to allow for the
clutch’s surface.
In addition, the heavy weight allows for more inertia once it is spinning.
Flywheels are usually produced by the casting method, and for now, sand casting is the most
common production process for flywheels. Depending on the application, the materials used are
nodular iron, steel or aluminium. Once cast, the flywheel is finished by machining and boring.
Next, a square or rectangular steel bar of a pre-set length is bent into a circle configuration and the
ends welded together, with the major diameter larger than the finished gear size.
The ring is then heated, and either stamped or bored to size on the minor diameter. Next, the gear
teeth are hobbed onto the ring, and hardened to improve strength and resistance. Lastly, the ring is
shrunk onto the flywheel (AmTech International, n.d.).
Performance Criteria
• High ductility
• Low density
• High yield strength
• Corrosion resistance
• High material index
A material having high ductility have a clear change in its shape before it breaks or burst
(flywheel burst like pressurize cylinder upon failure).
This property will help us to replace the part before it causes any serious damage to machine but
high ductility affect the working of flywheel in such a way that at very high rpm it start to lose its
shape, affecting the working where flywheel is enclose inside a machine. Low density of a
material allow you to have minimum mass under a given geometry, making your flywheel light
weight, easy to carry and easy to assemble and disassemble but low less mass result is less
kinetic energy of flywheel at given rpm which directly affect your output.
High yield strength of a material enables him to restore its original shape after elastic
deformation. It will help flywheel of resist the high rpm without being permanent deformed.
Giving desire shape to a material required machining and for this good machinability is required.
For long life material should be stable and should not react with surrounding atmosphere to form
oxides. For this flywheel material should have good corrosion resistance. Material index is the
most important property which shows material strength to density ratio enables us to select the
best material (Green Mechanic, 2016).
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Property Control Methods
1. Production volume
It is the number of pieces to be produce and it decide whether to use expandable mold or
permanent mold and this factor also decide whether the organization should go for automation of
the process or do it manually. If the volume is high the organization should go for automation to
reduce the unit production time and cost but if the volume is small and design variation is high
the organization should think of the integration of designing and manufacturing to have the
fastest response to change in design of product.
2. Product Size
Dimensions of the product is important for determine of the manufacturing process because of
the factors associates with the size like mold size, amount of molten material, pouring rate,
cooling rate and total solidification time.
3. Product shape features
Product shape features defines the complexity involves in the manufacturing of the product for
example irregular external shape and core for internal cavity can resist the flow of molten
material.
4. Product Value
Product value means the sensitivity of the function which it is going to perform. Product
associated with human life security need more careful manufacturing.
Sand casting which is most widely used manufacturing process was selected by manufacturer
because of low production volume, small size, simple shape, and low product value. This can
produce near net shape and can provide you desire mechanical properties using chillers or by
careful design of mold V/A ratio. Sand use in this process can be reused again and again and
waste material because of molding can be recycled making this process highly economical.
Automation of sand casting can also be done to reduce the unit production time. Sand casting is a
simple process but still there are some problems associated with it.
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Golf Club Head
Overview
In this chapter a vast amount of information will be unwrapped. Some of the information that can
be anticipated are:
•
•
•
•
Description of the golf club head and its usage.
The performance criteria and control.
The materials use to make the golf club head.
The manufacturing processes.
What is a golf club head?
A golf club is used to strike the ball in the game of golf. The golf club consist of a long shaft
with a grip on one end and a weighted head on the other. The head is positioned sideways at a
sharp angle to the shaft, and the striking face of the head is graduated to give the ball a certain
amount of upward flight. There are different classes of golf club to aid with different upward
flight, with that said, a golf player is allotted to take a maximum of 14 golf clubs per match.
These 14 variations of golf clubs differ in angle of projection, striking effect, the type of spin you
want etc., some of these clubs are:
•
•
•
•
•
•
•
•
Drivers
Fairways
Hybrids
Iron
52° wedge
56° wedge
60° wedge
Putters
Although the golf club consist of different parts, the sole idea is to discuss a specific part, the
golf club head. The golf club head is a vital part of the club, providing the platform to interact
the golf ball. The golf club head also comprises of several parts. These parts are:
•
•
•
•
•
•
•
Hosel
Ferrule
Heel
Face
Sole
Toe
Crown
Figure showing labelled golf
club head.
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Purpose of each part.
• Hosel- this is the entry point of the shaft into the head on any golf club.
• Ferrule- the sleeve prevents the head of the club from slipping off the shaft.
• Heel- this is where the club head is attached to the shaft.
• Face- this is the part of the club head which interacts with the ball.
• Sole- this is where the club rests on the ground in playing position.
• Toe- far end of the club head (farthest from the hosel/neck/shaft).
• Crown-is the part of the club that you see when you are in the address position, looking
down.
The performance criteria and control.
In the production of practically everything, consideration of the materials to be used is
important. Another important tip in production is performance criteria and control. Some key
points in the production of golf club head are:
• Biological and Chemical Factors of the Material- this has to do with whether the
materials are biocompatible.
• Mechanical Factors of the Material- this has to do with the mechanical properties of
the material.
• Aesthetic Factors of the Material- this has to do with the appearance of the material.
Why should these performance criteria be noted when creating a golf club head?
• Biological and chemical factors are important because chemicals are reactive, and
this reactivity can either improve or lessen the performance of the golf club head.
Personally speaking, I believe this is the most important criteria when selecting
materials to make golf club head. Without the perfection of this criteria the success
rate of production will be low. Lack of this criteria can create faulty productions
which could be bad for the company.
• Mechanical factor is another important factor to consider when making golf club
heads. The golf club head has to possess a property of hardness (similar to the golf
ball) to resist penetration, high fatigue strength which is a good factor in the
durability of the material, high yield strength to resist permanent deformation,
toughness and ductility (to some extent for design purposes).
• Aesthetic Factors is key to rank up productions. People are attracted to beauty and
unique in all aspects of life. So, this factor is a plus in the manufacturing of golf
clubs.
The materials use to make the golf club head.
Golfers have many options available to them regarding club head materials. Availability of golf
club head materials are:
• Titanium.
The use of titanium for golf clubs came from the technology used in the aerospace industry. The
first golf clubs made from titanium date back to the early 1990’s and quickly became the
material of choice for driver heads due to the high strength-to-weight ratio. Titanium is lighter
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than stainless steel and allows the designer to manufacturer a much larger club head that meets
the weight specifications of a normal driver. The strength of the material has increased durability
for even the strongest golfers in the world.
There are many different titanium alloys (materials added to the raw titanium) to change both the
weight and strengths requirements. With driver heads reaching the maximum volume of 460
cubic centimetres, the most common alloy is 6/4 Titanium, by which 90% of the material is
titanium, 6% is aluminium and 4% is vanadium. There are many other alloys or grades of
titanium (sometimes called Beta Titanium) such as 15-3-3-3, SP700, 10-2-3, etc. available to the
club designer. If the higher grade of titanium is used, then it is normally for the face material
only and not the entire head.
The United States Golf Association (USGA) and the Royal and Ancient Golf Club of St.
Andrews (R&A) – the two governing bodies in golf – established rules for how fast a ball can
come off of the club face of a driver. Most manufacturers make drivers that go to this limit
without exceeding it, so there really is no advantage of one material over another. Typically,
smaller drivers (under 400cc) would utilize the higher cost beta titanium to increase how fast the
ball comes off the face. But with clubs in the 460cc range, standard 6/4 titanium will be
sufficient material for the maximum allowable ball speed. (Folely, n.d.)
Titanium can also be used in other clubs, but normally you do not see it much for a couple of
reasons. First, titanium is much more expensive than stainless steel used in fairway woods,
hybrids, and irons. Second, the reason for titanium is for the strength and lightweight nature. If
a fairway wood were made with titanium, it would normally be made much larger in size to
achieve a normal weight. By doing so the head could become much taller and makes it
effectively harder to hit off the fairway. The alternative is using a dense metal or affixing a
heavier weight on the sole. The same can be said for titanium irons. However, you may have
seen some irons with a titanium insert as a way of increasing the ball speed at impact verses an
all stainless steel clubhead.
• Stainless Steel.
Stainless steel is the most used material in golf. The material is generally inexpensive and easy to
cast into all the shapes that you see golf clubs made plus durable enough for everyday play.
There are two main types of stainless steel used in golf club heads. One is 17-4 stainless steel
(comprising of no more than 0.07% carbon, between 15% and 17% chromium, 4% nickel, 2.75%
copper, and 75% iron and trace elements). 17-4 used primarily for metal woods, hybrids, and
some irons. The other type of stainless steel is 431 (comprising of no more than 0.2% carbon, 1517% chromium, 1.25 – 2.5% nickel, and the remainder being iron and a few trace elements).
This grade of stainless steel is used for irons and putters, but does have sufficient strength for
fairway woods and hybrids.
The majority of fairway woods today are manufactured from 17-4 stainless steel. Drivers can
also be made of 17-4, but due to the high density of the material, the limit on size is
approximately 250cc without the risk of cracking during normal play. Because golfers prefer
larger, easier-to-hit drivers, virtually no drivers today are even manufactured from stainless
steel. Investment cast irons can be made from either 431 or 17-4 grades. The 17-4 is slightly
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harder of the two. This allows the 431 to be adjusted for loft or lie a little more easily, but other
than that, there is no one greater advantage of one verse the other.
• Specialty Stainless Steel (Maraging Steel).
In addition to the number of materials used in golf club head manufacturing is maraging steel,
which is an alloy or family of steel with unique properties. Typically maraging steels are harder
than non-maraging steels like 431 or 17-4 and used primarily for face inserts rather than the
whole head. A driver head can be produced wholly from maraging steel, but there is still a limit
on the size of the head (roughly in the low-300cc range). Plus, the cost of the head would not be
that much less expensive than one made from titanium.
Since the maraging steels are harder, the face insert can be made thinner than the normal
stainless steel graded used in golf. As a result, the ball coming off the face will have a slightly
high ball velocity upon impact. Maraging steels are more expensive to produce, therefore would
be more in the premium price range, which is the trade-off for the higher performance.
• Aluminium.
Aluminium is a much lighter material than stainless steel. Early metal woods made from
aluminium back in 1970’s and 80’s was not very strong or durable. This caused these low-cost
club heads to gain a bad reputation for easily scratching and denting that still carries over today.
However, the aluminium alloys today are much better than those used in the past and the head
sized can be made to the maximum size for drivers (460cc) under the Rules of Golf or even
larger.
Heads manufactured from aluminium are much lower in cost than even stainless steel, which
makes these clubs more affordable and ideal for woods of starter sets or junior sets. The only
downside to the aluminium is that the walls must be made thicker as not to crack or cave in.
Therefore, the ball speed coming off the face would be less than a comparable titanium driver.
• Carbon Steel.
Carbon graphite is an extremely lightweight material and can be used to create a wood (usually
with some sort of metallic soleplate for durability and additional weight). Few clubs today are
produced primarily from carbon graphite; however, there are a number that incorporate the
carbon graphite material in the design.
Carbon graphite is less dense than any other material used in golf and a perfect choice to replace
the top shell (or crown or top of the head). The weight savings from incorporating the carbon
graphite in the crown, allows additional weight to be repositioned elsewhere in the heads to
improve the design. Heads made from or partially from carbon graphite demand a premium price
and can be found, not only in drivers, but fairway woods and hybrids as well.
Used in either irons, wedges or putters, carbon steel has been used in golf clubs for
centuries. Most will associate carbon steel irons and wedges to be forged, as this was the
primary method of fabricating these clubs. However, certain alloys of carbon steel can be cast as
well (8620 carbon steel) to produce a club head. Regardless, carbon steel is a soft, malleable
material that will rust without some sort of protective chrome finish.
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More skilled golfers tend to gravitate toward models made of carbon steel as some say that can
tell a difference in the feel of the material verses the harder stainless steel. More importantly,
head made of softer, carbon steel tend to be less of a game improvement design and are tended
more for the lower handicapped golfer.
Some of which are intentionally un-chromed to rust through normal use. The idea behind the
unplated carbon steel wedges is softer feel and supposable greater spin. Irons, wedges, and
putters produced from carbon steel will be more expensive than stainless steel.
• Zinc.
Heads produced from zinc are the least expensive of all the materials. Used mostly for irons,
wedges and putters in both starter sets and junior sets, zinc heads are less durable than their
stainless steel counterparts. Zinc heads can be identified by their non-magnetic properties and
their larger-than-normal hosel diameters.
• Wood.
Wooden woods are rarely found as a club head material option anymore as it has lost favour
amongst golfers to titanium drivers and stainless fairway woods.
The manufacturing processes
Creating a golf club head is a crucial process. There are several manufacturing processes that
could be used to create the golf club head: sand casting, blow moulding, investment casting, etc.
However, I chose the process of casting.
•
What is casting?
Casting is a manufacturing process in which a liquid material is usually poured into a mold,
which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified
part is also known as a casting, which is ejected or broken out of the mold to complete the
process. Casting materials are usually metals or various time setting materials that cure after
mixing two or more components together.
Step to step process to manufacture a golf club head.
Before a golf club is put into production, it is designed on a computer using sophisticated
CAD software. The computer design is used as
the basis for the development of a proprietary
mold. Once a mold has been produced it is used
in the production of every club head.
The figure above is showing a mirrored mold of the golf club head. The mold has two parts to it
and has a small opening on the side.
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(Image showing wax injection moulding machine).
The mold is inserted into a wax injection moulding machine and boiling hot wax is squirted
into the mold. The outcome is a golf club head that is made of wax. A wax mold is made for
every piece that is manufactured. For example, a set of 9 irons will require 9 wax moulds,
each representing a different loft.
The wax moulds are then checked individually for minor blemishes and a fine nail file is
used to remove excess wax particles that might be present on the mold. This is important as
any imperfections on the wax mold will be present in the production club head. Again, this
takes place manually, and each club head piece is subject to this process.
The wax club heads are then melted onto a wax tree in groups of 14 and dipped into
quicksand.
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The quicksand adheres to the wax and forms a shell around the outskirts of the mold. The
tree is left to dry in a refrigerated room and this process is repeated five times. Quicksand is
used because it can withstand the extreme temperatures required when pouring the molten
iron and because of its ability to form a perfectly smooth shell around the intricate details of
the wax club head. Once the fifth round of quicksand has dried, the tree is inserted into a
steam oven. The steam heats up the wax and it melts out from the inside of the quicksand
tree. The top of the quicksand tree is shaped liked a funnel making it easy to pour the
molten iron into the quicksand shell.
The quicksand moulds are transported to a furnace. A stainless-steel alloy is heated up to
1500° Celsius at which point it becomes molten liquid and glows red hot.
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Once the metal is molten and the quicksand is the same temperature, the quicksand moulds
are removed from the furnace and walked across to the pouring station where the molten
steel is poured into the quicksand mold.
The red-hot quicksand moulds containing the molten metal are placed on a shelf of sand and
left to harden. Once the steel has hardened, the quicksand outer shell is cracked off the iron
moulds and the unpolished golf heads are exposed. At this stage, the club heads are still
connected to the tree.
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The club heads are individually cut off the tree by a metal cutter and the finishing process
begins from a head. The finishing process is a long process. It begins by polishing the club
head and sandblasting the face. Once the club has been polished and sand blasted, it goes
through a quality assurance process where the loft, lie, weight, hosel diameter and variance
measurements are tested to ensure they fall within the strict tolerances set by the
manufacturer of the clubs and by the R&A. The club heads are then trucked to a different
location where skilled workers paint the logos and score lines onto the club head. The logos
are a part of the original mold however they must be coloured in before they are ready to be
sold and used.
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Golf ball
Overview
In this chapter a vast amount of information will be unwrapped. Some of the information that can
be anticipated are:
•
•
•
•
Description of the golf ball and its usage.
The performance criteria and control.
The materials use to make the golf ball.
The manufacturing processes.
What is a golf ball?
A golf ball is a special ball designed to be used in the game of golf. Under the rules of golf, a
golf ball has a mass no more than 1.620 oz (45.93 grams), has a diameter not less than 1.680 in
(42.67 mm), and performs within specified velocity, distance, and symmetry limits. Like golf
clubs, golf balls are subject to testing and approval by the R&A. The first golf ball similar in size
to today's came into existence around five or six hundred years ago, when the Dutchmen stuffed
feathers into a 1.5 in (3.75 cm) leather pouch. The golf ball is composed of a cover and core.
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Types of golf balls.
There are three types of golf balls, they are:
•
•
•
Two-piece- have a hard cover and solid inner core, they are created for distance and
durability. These types of balls are good for beginners as it can hold up to being hit into
the trees or hazards.
Multi-layered- possesses a liquid or solid core with a moulded rubber outer core. Its
cover is softer and designed for higher spin rates. The softer feel and high spin allow the
intermediate golfer more control and better stopping power. These balls are more
expensive and not as durable as the two-piece ball.
High-performance- combines a high-spin capability and distance for the low-handicap
golfer. These balls are not durable and are quite costly. (Scott, 2017)
The performance criteria and control.
There are many factors that designers should consider when choosing a material including the
desired properties for the application and the available materials. By fully understanding the
materials, designers can then make well-informed choices. The following must be taken into
consideration when making golf balls:
• Biological and Chemical Factors of the Material- this has to do with whether the
materials are biocompatible.
• Mechanical Factors of the Material- this has to do with the mechanical properties of
the material.
• Aesthetic Factors of the Material- this has to do with the appearance of the material.
• Surface Finish
• Durability
• Appearance
• Friction
• Weight
Why should these performance criteria be noted when creating a golf ball?
• Biological and chemical factors are important because chemicals are reactive, and
this reactivity can either improve or lessen the performance of the golf balls.
Personally speaking, I believe this is the most important criteria when selecting
materials to make golf ball. Without the perfection of this criteria the success rate of
production will be low. Lack of this criteria can create faulty productions which
could be bad for the company.
• Mechanical factor is another important factor to consider when making golf ball. The
golf ball must possess a property of hardness to resist penetration, high fatigue
strength which is a good factor in the durability of the material, high yield strength to
resist permanent deformation, toughness, and ductility.
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• Aesthetic Factors is key to rank up productions. People are attracted to beauty and
•
•
unique in all aspects of life. So, this factor is a plus in the manufacturing of golf
balls.
Weight is a prime factor in the game of golf. Lighter balls will produce less
gravitational pull.
Appearance- this factor is not much of a big deal, however, can be useful if a golfer
has difficulty seeing the colour white.
The materials use to make the golf ball.
Golf ball makers use different levels of firmness and different materials in both the core and
cover of the ball to appeal to a wide audience. Modern golf ball covers are typically made of
surlyn, urethane or elastomer.
• Surlyn
Surlyn is a material made from ionomer resin that was created by the brand DuPont. Since the
mid-1960s, surlyn has been used on the outer shells of golf balls. The build is hard and synthetic
material that is the cheapest and most durable of the three. It is usually found in the covers of
two-piece golf balls. It provides low spin when hitting tee shots. Most Surlyn golf balls are hard
two-piece balls. They usually have less control.
• Urethane
Urethane is a soft, synthetic material with higher-spin characteristics because the club face can
"grab" the ball for slightly longer. Urethane covers are used mostly on multi-layered balls.
• Elastomer
Elastomer is the softest and most expensive choice of cover. This less-durable material covers
many of the premium high-performance balls. (Rose, n.d.)
The manufacturing processes.
The manufacturing process of the golf ball can be difficult and time consuming. Golf balls can
require more than 80 different manufacturing steps and 32 inspections, taking up to 30 days to
make one ball. Two-piece balls require about half of these steps and can be produced in as little
as one day. The common steps are:
•
Forming the Centre.
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The centre of the two-piece ball is a
moulded core. It is a blend of several
different ingredients, all of which are
chemically reactive to give a rubber
type compound. After heat and
pressure is applied, a core of about 1.5
inches (3.75 cm) is formed.
•
Forming the cover and
dimples.
Injection moulding or compression
moulding is used to form the cover and
dimples on a two-piece ball using a
two-piece mold. In injection moulding,
the core is centred within a mold cavity by pins, and molten thermoplastic is injected into the
dimpled cavity surrounding the core. Heat and pressure cause the cover material to flow to join
with the centre forming the dimpled shape and size of the finished ball. As the plastic cools and
hardens, the pins are retracted, and the finished balls are removed.
With compression moulding, the cover is first injection moulded into two hollow hemispheres.
These are positioned around the core, heated, and then pressed together, using a mold which
fuses the cover to the core and forms the dimples. Three-piece balls are all compression moulded
since the hot plastic flowing through would distort and probably cause breaks in the rubber
threads.
• Polishing, painting, and final coating.
Rough spots and the seam on the moulded cover are removed. Two coats of paint are applied to
the ball. Each ball sits on two posts, which spins so that the paint is applied uniformly. Spray
guns that are automatically controlled are used to apply the paint. Next, the ball is stamped with
the logo. The final step is the application of a clear coat for high sheen and scuff resistance.
(Bodamer, n.d.)
Drying and Packaging.
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After the paint is applied, the balls are loaded into containers and placed in large dryers. After
drying, the balls are ready for packaging in boxes and other containers.
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$1 Coin
The Jamaican $1 dollar coin is small circular shiny (silver) nickel-plated steel with a national
hero on one side and the Jamaican coat of arm on the other. It has been the replacement for the
former demonetized cupronickel $1 coin. It has been the monetary value of use from 1990 to
present and changed shape over the years from a hexagonal shape to the present form.
Application of Coins: Apart from the monetary use of coin, there are a wide variety of
household uses that a coin brings with it due to its various properties.
•
Use a medium for the exchange of goods and services.
•
To tighten screws
•
To operate machines such as phone booth
•
Used to test tire tread
Performance Criteria
Mechanical Properties:
•
•
•
•
•
•
High tensile strength
very good young modulus
good shear modulus (the ratio of shear stress to shear strain)
Ductility is quite good
Very good elastic limit
Ability to withstand high temperatures and pressures
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While it is that the steel is plated with nickel most of the mechanical properties are contributed
by the steel. The above stated mechanical properties are very important to produce coin as the
strong tensile strength and shear modulus etc. are needed to withstand pressures of high
magnitude. For example, several times coins are running over by cars and trucks. When this
happens, the coin remains in its original shape. This helps with the number of coins be used
replaced yearly.
Electrical Properties:
Commercially pure nickel has high electrical conductivity, however nickel-plated steel is
commercially pure nickel has low electrical conductivity. This is very important for the products
that nickel-plated steel are used to make because for example where it is used to make gas
chambers, conducting an electric charge might cause a fire which is very hazardous.
Chemical Properties:
Nickel-plated steel is used for their outstanding corrosion and high temperature resistance. It is
also known for its outstanding high temperature strength and oxidation resistance. In essence, it
is the presence of the nickel that gives the nickel-plated steel great corrosion resistance. This
property is very important for the products made such as the one-dollar coin as it gives the coin a
long-life span without corroding in rain wind etc.
Physical Properties:
•
•
•
•
•
•
•
Silvery look due to nickel plating
flat circular shaped
Weight 2.9g
Dimension 18.5 × 18.5 mm
Steel alloy density ranges 7.75 and 8.05 g/cm3
Melting Point ranges from 1430-1510oC
Magnetic
The physical properties are crucial to the coin as it helps with identity of the money and being
light weight makes it easy to carry around.
Types of materials used
While in most cases steel is the main constituent of coins made there are different types of
materials that can be used to make the $1 coin:
•
copper-nickel (Cupronickel)- Monel 400 (N04400)
Composition: Minor additions of aluminum and titanium to the nickel-copper matrix.
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Structure:
ordered CuNi (CN)4 sheets with copper(ii) in a square-planar environment
•
Copper-plated steel -
Composition:
0.35% carbon
3.5% nickel
0.2% Silicon
0.54% Manganese
0.16% Phosphorus
98.7% Iron
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Material Selection
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Nickel-plated steel-
Diagram showing the structure of Nickel-Steel alloy
Manufacturing Processes:
To make Nickle-steel Alloys manufacturers start with the purest available raw materials to
achieve the required chemical composition. The alloys are then Melted, Hot-Rolled and
Processed to final sizes using state-of-the-art technology.
Raw Material
•
Only virgin materials used in melting for all alloys.
•
Nickel is sourced from reputable international suppliers.
•
All other metals sourced from high-quality suppliers.
•
Most of the metals used are pure/electrolytic grade to ensure highest purity levels.
Melting
•
Completely integrated manufacturing facility; starting from the melting stage.
•
Melting performed in modern electric furnaces.
•
Capacity to melt in different batch sizes- big and small.
•
Special techniques to control impurities and inclusions.
•
Unique processing technique ensures consistency and high surface quality.
Hot Rolling
•
Ingots pre-heated (red hot) and then hot-rolled on a high-speed rolling mill.
•
Ingots hot rolled to rods or strip form.
•
Assignment of roll-passes for different alloys.
•
Rolling carried out at high speeds to prevent high temperature oxidation of materials.
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Wire Drawing
•
Heavy gauge wire drawn to size on modern high-speed drawing blocks.
•
Wet drawing for wire sizes below 2 mm.
•
Over 60 different types of wet wire drawing machines available based upon wire
diameter and alloy.
•
Diamond dies used to obtain bright and smooth surface quality.
•
Super fine wires up to diameters 0.05 mm also produced for special applications.
Annealing
•
In-house batch annealing and continuous annealing furnaces
•
Hot-rolled material subjected to batch annealing in controlled atmosphere furnaces.
•
Annealed material thoroughly cleaned and coated with a suitable lubricant.
•
Continuous annealing for intermediate and fine size wire for desired surface finish.
•
JLC has over 15 continuous annealing furnaces designed to anneal various Ni alloys.
•
All furnaces have inert atmosphere to give bright annealed wires.
Testing & Packing
•
All alloys produced undergo several stages of quality control for strict adherence to
specifications.
•
In-house, well-equipped physical and chemical testing lab supports the production.
•
Well-equipped packaging department to ensure that all material is shipped defect-free
and safely packaged.
•
Treated and IPPC marked wooden boxes.
•
Standard spools used as per DIN standards. Drum/pail packing is also available.
•
Thicker wires supplied in coils on pellets.
•
Specialized packaging in other forms provided as per the customer requirement.
Alloy steel is a mixture of iron ore, chromium, silicon, nickel, carbon, and manganese, and it is
one of the most versatile metals around. There are 57 types of alloy steel, each with properties
based on the percentage amount of each element mixed into the alloy. Since the 1960s, electric
furnaces and basic oxygen furnaces have been the standard forms of industrial alloy steel
production, while other methods have become outdated. The technology of steel production and
the quality of output have advanced, but the actual steps to manufacturing alloy steel have not
changed and are rather simple to understand.
Melt the base alloys in an electric furnace at 3,000 degrees Fahrenheit for 8 to 12 hours. Then
anneal the molten steel by rapidly cooling and heating it in a controlled sequence. Dip the steel in
a bath of hydrofluoric acid. The dip removes the buildup of mill scale caused by annealing. Mill
scale is an iron oxide that peels from the surface of hot steel when it is air-cooled. Anneal and
descale the steel one more time.
Pour the molten unfinished steel into casts, blooms, billets, and slabs. Blooms are long
rectangular bars; billets are round or square ingots; and slabs are long, thick sheets. Cast the
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blooms, billets, and slabs by pouring them into molds and allow them to cool for four hours. Roll
the blooms, billets, and slabs through heated rollers to shear off the ends as scrap and to burn
away surface defects. Each rolling method brings the steel closer to the final product. Use a
series of grinders and abrasive rollers for a reflective finish.
Property Control Method
The steel constituent coin was plated with nickel to prevent erosion as nickel has a very high
corrosion resistance. In addition, it is an alloy of several elements, which adds to its mechanical
and physical properties. Being the multi-phase metal that it is, it is hardened by annealing which
is stated in the manufacturing process.
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Airplane Wings
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Definition
A wing is a thin and linear section of the plane found on both sides of the fuselage (main part of
a plane) that produces lift and helps with the maneuvering of the plane through air and fluids.
Description
The structural make-up of the airplane wings is that they are held together and supported by
metal spars, ribs, and stringers. While the covering of the plane is made of either fabric (such as
carbon fibers), aluminum, or composite material shell. Wing is a rectangular finned shape
structure which changes shape based on the changes of the flaps and ailerons. The wing consists
of two edges: the leading edge and the trailing edge. The trailing edge consist of the spoilers and
the ailerons which changes the shape of the wing throughout the different journeys of the flight.
Ailerons are found near the tips of wings' trailing edges. They are rectangular-shaped airfoils that
rise to disturb the airflow over the wing. Ailerons are used to turn the airplane by creating more
lift on one wing than the other. Flaps are smaller airfoils found on the rear parts of the wings
nearest to the fuselage. Flaps can be extended to increase the wing surface area, creating more
lift for takeoff and landing. However while it is customary to have planes with wings that are
linear and straight, there are wings that have edges with curved or vertical tips called winglets
which reduce drag and enable the wings to produce lift more efficiently. (Bowler, 2014)
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Application of wings
The wing is composed of different structures, which all play a part in the different aircraft phase
whether it is take-off, landing, de-icing etc. Due to its long and slender shape, it is used to reduce
drag and create lifts at a faster rate. While the main purpose of the wing is to create efficiency in
climbing, rotating, descending, and cruising. It is also important to note that the carbon fibre
covering that are used in most planes are used to gain aerodynamic performance and hold the
engines that provide the power. In addition to the information stated, the wings are equipped
with deicing system being the bleed air valve system, which allows hot air to travel along the
leading edges, which warms up melting the ice accumulated. On the other hand, there are deicing boot system for which are inflatable rubber attached to the leading edge. As ice builds up
along the wing, the boot inflates breaking up the ice formed. (Bowler, 2014)
Performance Criteria
The selection of the material used in the production of the airplane wing is one of the most
crucial parts in its production. This is because the performance criteria are very much relatable to
the operational requirement of the product and not just the material. However, it is important to
note that it is the material, which contributes to the performance criteria. While it is that airplanes
wings are covered with aluminum or carbon fiber this piece will be focusing on carbon fiber
material which makes up the wing of the airplane. Carbon fibers are made of long carbon
crystals aligned in a long axis with aromatic molecular bonds. It began to be the choice of
material due to its mechanical, physical, electrical, and chemical properties.
Mechanical Properties
Mechanical Properties looks at the reaction or the physical properties that a material exhibits
when placed under stress or when a force is applied. e.g. Fatigue limit, tensile strength, or
modulus of elasticity. Carbon fibers has very good resistance to fatigue due to its carbon fiber
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Material Selection
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composites, while damage to carbon fiber is seen as decrease in its stiffness. In addition to this,
carbon fiber is well known for its high tensile strength or ultimate strength. Tensile strength is
ultimate stress that a material can undergo just before it breaks or necks (which is when the
cross-sectional area starts to contract which is measured in force per unit area- pressure). This
property is very important regarding the production of the wing because the wing undergoes high
speed with a great amount air resistance. It also important to mention that the wing stores the fuel
load and hold the engines attached to it. With these loads being added to the wing then the high
tensile strength becomes a necessity to withstand the loads without breaking. Stated below are
some mechanical properties shown with their respective measurement:
•
•
•
•
•
Carbon fibers have high strength (3–7 GPa)
Low Coefficient of Thermal Expansion
High modulus (200–500 GPa)
Compressive strength (1–3 GPa)
Shear modulus (10–15 GPa)
Chemical Properties
Chemical properties are the changes observed in a material or substance when it partakes in a
reaction. Carbon fiber is corrosion resistant and chemically stable which is very good for
airplane use as it prevents the wing from corroding when it reacts with rain snow etc. This adds a
longer life span to the wing and helps with less money being spent on maintenance. This
property is very important because the corrosion of the wing means that the covering of the wing
will be affected thus causing the plane’s wing to dismantle and to fall apart when met up with
much drag from the wind when cruising at a very fast speed. (AirCraft Basic Construction, 2000)
Physical Properties of Carbon Fiber:
•
•
•
•
•
•
•
•
Low density (1.75–2.00 g/cm3) which is related to mass; hence it means that they are
usually light in weight.
Light colored appearance such as white or grey
4200 °C
The opacity is usually very high allowing no electromagnetic light to pass through.
Carbon fibers are non-magnetic
The melting point usually has a temperature that ranges from 1,150 to 1,200 °C.
The viscosity is good as it thick to withstand the strong drag it encounters giving it
much resistance to deformation at any given rate.
Carbon fiber is especially known for its high flexibility which is the reason it is used
often in aerospace.
The stated physical properties are very important in aerospace. This is so because when taking
into considering the weight of the carbon fiber, which is very important to help with, take off and
reduce the fuel consumption. Whenever the plane takes off it burns much fuel to act against
gravity and the weight of the plane. In reducing the weight then it burns less fuel to take off
saving the airlines millions from refueling the plane. They are usually light colored appearances
which helps to keep the plan cool as this is set behind the principle of albedo effect where
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Material Selection
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electromagnetic rays from the sun is reflected back into space which helps to reduce the amount
of heat conducted in the wing which is where the fuel is stored.
Electrical Property of Carbon Fiber:
Carbon fibers are not electrically conductive which is very useful for the airplane’s safety.
Throughout the year, airplanes are often met up with unfavorable weathers which can be very
detrimental to the safety of the souls on board. Being that carbon fibers which makes up the
wings are not electrically conductive then it means therefore that when in a thunderstorm which
is characterized by heavy rainfall and lightning. Then it will not conduct the lightning as this can
start a fire especially because the fuel is contained in the wings of the plane. Apart from
conducting lightning, being electrically non-conductive then it means that it will not be affected
by galvanic corrosion. (Bhatt & Goe, 2017)
The type of materials used to make airplane wings:
Over the years Airplane wings have been made from several materials such as: aluminum alloy
and of lately carbon fiber composites.
Aluminum:
Aluminum alloys are widely used in modern aircraft construction. Aluminum alloys are valuable
because they have a high strength-to-weight ratio. Aluminum alloys are corrosion resistant and
comparatively easy to fabricate. The outstanding characteristic of aluminum is its lightweight
Carbon Fiber:
High-performance aircraft require an extra high strength-to-weight ratio material. Fabrication of
composite materials satisfies this special requirement. Composite materials are constructed by
using several layers of bonding materials (graphite epoxy or boron epoxy). These materials are
mechanically fastened to conventional substructures. Another type of composite construction
consists of thin graphite epoxy skins bonded to an aluminum honeycomb core. Carbon fiber is
extremely strong, thin fiber made by heating synthetic fibers, such as rayon, until charred, and
then layering in cross sections. (Bhatt & Goe, 2017)
Materials
used
(Alloys)
Aluminum
Commercial
Number
Composition of
the material
7075 aluminum
alloys
5.6–6.1% zinc
2.1–
2.5%magnesium
1.2–1.6%
copper, and less
than a half
percent of
silicon, iron,
manganese,
titanium,
chromium, and
other metals
Chemistry/Structure of the material
Large extrusion with the section near the
surface showing a layer of course
recrystallized grain overlying fine subgrains
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Material Selection
Carbon
Fiber
Material Science
Composite 101
or carbon
composite
Thermosetting
Plastics
Chemical
Name: graphite
fiber
The composite
material may
contain aramid
(e.g. Kevlar,
Twaron), ultrahigh-molecularweight
polyethylene
(UHMWPE),
aluminum, or
glass fibers in
addition to
carbon fibers.
They usually
involve
additives which
contributes to
the structure of
the carbon
composite.
Group Assignment
Consist of a highly cross-linked, 3D
network. Bonds prevent chains moving
relative to each other. The carbon atoms
are bonded together in microscopic
crystals (hexagonal aromatic rings) that
are aligned parallel to the long axis of the
fiber. The crystal alignment makes the
fiber incredibly strong for its size.
Several thousand carbon fibers are
twisted together to form a yarn, which
may be used by itself or woven into a
fabric. Further heating at 700:C causes
these rings to become aromatic pyridine
groups due to the loss of hydrogen from
the carbon atoms.
Manufacturing Properties
There are several ways in which an airplane wings are made, which are as follows: vacuum
bagging, molding and compression molding and high-tech computer assisted design.
Diagram showing assemblage of an aircraft wing
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Molding method:
Wing geometry affects every aspect of an aircraft's flight. The wing area will usually be dictated
by the desired stalling speed but the overall shape of the planform and other detail aspects may
be influenced by wing layout factors. The construction of the wing starts with the rib which
defines the airfoil shape. Ribs can be made of wood, metal, plastic or even composites. Firstly,
the carbon fiber parts are produced by layering sheets of carbon fiber cloth into a mold in the
shape of the final product. The alignment and weave of the cloth fibers is chosen to optimize the
strength and stiffness properties of the resulting material. The mold is then filled with epoxy and
is heated or air-cured. The resulting part is very corrosion-resistant, stiff, and strong for its
weight. Parts used in less critical areas are manufactured by draping cloth over a mold, with
epoxy either preimpregnated into the fibers or "painted" over it. High-performance parts using
single molds are often vacuum-bagged and/or autoclave-cured, because even small air bubbles in
the material will reduce strength.
Secondly, the ribs are made using either grade aluminum or steel, which is corrosion resistant
and possesses great tensile strength. Ribs are made and placed unto a metal bar and rubber
forming die. A hydraulic press applies 150 tons of pressure stamping the rib to the die shape.
Using a grinder, the sharp edges are smooth out and the plastic film removed that protects the rib
from scratches. The same process is used to make the spar which is used to make the entire
length of the wing. This takes even more pressure (222 tons) because this material is three times
thicker than the ones used for the ribs. Spring clamps are manually pushed into the spar to ensure
the ribs are aligned evenly, which holds the ribs in position. Workers hand drilled for larger
rivets then smooth out the sharp edges. The completed airframe receives the carbon fiber
covering after which spring clamps are used to position the covering unto the frame. The same
procedure is used for the leading-edge wing nose. Once everything is together with spring
clamps, the assembly is permanently riveted. While welders fuse the wings field tank using an
organic gas torch. The tank is fitted in the wing chamber then secured by bolting steel belts unto
the spars. After which the tanks covering plate is screwed unto the wing. Lastly, the wing tip is
attached, and the wing is assembled unto the fuselage, which is the main part of the airplane.
(Experimental Aircraft Info, n.d.)
Property-control methods:
Carbon fiber usually contains additives, where the most common additive is silica, but other
additives such as rubber and carbon nanotubes can be used. These additives are very vital to the
material as it helps with the strength and rigidity of the material (such as reinforced polymer).
Also, the carbon fiber or carbon fiber reinforced polymer usually contains epoxy resin which
gives it a good mechanical property. Carbon fiber may contain precursors which adds to its
flexibility which is very vital when the wings are dancing against the motion of the drag force.
(Bhatt & Goe, 2017)
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Bulletproof Vest
Description and application
A “Bulletproof vest” more accurately a
bullet resistant vest is a type of armour that
is used to protect the torso from firearm
projectiles. Body protection was being use
from early as 400 B.C, it can be seen in the
Roman empire, Greek empire, Medieval
and Modern day. Body armour was
formalized in 1538 where steel plates were
used in the gear. The body protection is
important for the torso area contain most
vital organs. Effective body Armor was
introduced in the 1940s, where it was used
by military and law enforcers. The vest was
made up of ballistic nylon at the time until
in 1965, Stephanie Kwolek created Kevlar.
Kevlar is the most effective material
because of its high resistance, strength, and
light weight. The vests nowadays are made
up of layers of polyethylene, strong fibres,
ceramics, and Kevlar.
Bulletproof vest is important whereas the
different layers of the vest absorbs the impact so that the wearer does not suffer from the
penetration of the shrapnel or bullet but probably minor internal bruising. The vest is made to
spread force of a bullet in larger area. There are hard body and soft body vest. Hard body is
strengthened by steel plates to make stronger and effective however it is heavier. Soft body
however is more light weight they are most worn by police officers or guards whereas hard body
is for the military.
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Materials
• Kevlar
This is a very strong plastic that is made from
condensation polymerization. To make Kevlar is
expensive because it requires a lot of concentrated
sulphuric acid. Kevlar is a crystal liquid compound that
can be woven into fiber. There are different types of
Kevlar some are:
Kevlar K-29 – Use to make Cables, tires, and brake
lining
Kevlar 119 – Can be stretched more, it is flexible and
has high fatigue resistance.
Kevlar that is applicable in bulletproof vest has a high
strength to weight ratio like Kevlar K129 and Kevlar
KM2. Kevlar fiber relative density is 1.44 whereas its
tensile strength is 3620 MPa. It has such high strength
because of its natural intermolecular forces. It has strong
hydrogen bonds as well as the aromatic bonding which is a ring like structure bonded with
another aromatic structure.
• UHMWPE
It is a high molecular weight polyethylene made from polymerization. This also has a high
strength to weight ratio. This material is useful in stab proof vest whereas it passes the “ice pick”
test. It is also use in bulletproof vest because of its ballistic resistance. Unlike Kevlar that lose
strength when exposed to UV light UHMPE does not lose its strength.
• Dyneema
Dyneema is the most used polyethylene use in
bulletproof vest. Kevlar is 5 times stronger than steel
where as Dyneema is 15 times stronger and 40%
stronger than Kevlar comparing their strength to
weight ratio. Dyneema have different fibers namely
HB212, HB56, SB115 and SB71. Bulletproof vest
with best performance is normally use Dyneema
along with Kevlar. The mix is better where as it
improves the flexibility and lowers the weight of the
vest. (Protection Group Danmark, n.d.)
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Material Selection
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Group Assignment
Manufacturing process
•
Making the cloth
To make Kevlar requires you do work in a lab and perform a polymerization experiment to
create poly-para-phenylene terephthalamide. Polymer is made using condensation
polymerization whereas long chain compound created with a crystalline liquid structure. A
process of wet spinning occurs in a spinneret (like a shower head) to form Kevlar fibre which is a
composite with carbon fibre and glass fibre. The fibre is then hardened, wound, twisted and
woven into a strong and stiff material. (Tex Tech Industries, 2020)
Spectra is laid parallel to the Kevlar and coated with resin to form a spectra cloth. Two sheets of
the cloth are placed perpendicular to each other and bonded together between two sheets of
polyethylene film.
•
Cutting the panel
The cloth is place on a table laying
out 8 or more layers depending on
the bulletproof protection level
(Level 1, Level 2, etc.). They are
placed in position and a handheld
machine is used to cut out the
pattern of each panel.
•
Sewing the panels
The panels are placed in position
and a stencil and chalk is used to
mark out the sewing pattern. Kevlar
vest are box stitched or quilt
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Material Selection
Material Science
Group Assignment
stitched. Box stitch is easier to do and it allows better movement of the vest therefore it is not as
stiff whereas quilt stitch is harder to do but it creates a stiff vest and all components of the vest
stays intact.
• Finishing the vest
The shells for the panel are held together whereas the panels are place in the shells. (How
Products are Made, n.d.)
Performance Criteria
Important criteria for designing this product are:
1.
2.
3.
4.
Flexibility
Weight
Tensile strength
Toughness
Flexibility is important because to allow better movement of the wearer. A solider wearing a
bulletproof vest is going to do a lot of movement and would need to be comfortable holding a
gun.
Weight is another important factor whereas mobility is important for the wearer. The person may
need to run and light weight equipment would be suitable.
Tensile strength is important to absorb the energy of ballistic projectiles to reduce internal
bruising.
Toughness is another important feature whereas the ballistic project will not penetrate the
material of the vest.
Property Control Method
To improve strength of bulletproof vest Graphene can be an added layer in making vest. It is
lightweight as well it is two times stronger than Kevlar it can absorb more energy from the
ballistic projectile. The only downfall is that is not as tough as Kevlar therefore it is between to
blend with other materials. A Cordura cover would also be beneficial to avoid wear of the vest
whereas it has a high wear resistance.
54
Material Selection
Material Science
Group Assignment
Cutlery Parts
Description and application
Cutlery parts is used worldwide
when preparing, serving, or eating
food. It is a handheld instrument to
make it easier to handle food other
than using your hand. Using Cutlery
parts is seen as “classier” than using
your hands or other means. Cutlery
parts are also known as silverware
and this term was developed in the
mid-19th century. The name
Silverware was because at the time
the Cutlery parts were made from
silver however from 1970s to now,
they are commonly made from
stainless steel. The most common
Cutlery parts are spoon, knife, and
fork, each has specific use. A spoon
is generally use when handling
liquid, fork is used to handle solid
food whereas it can penetrate the
food to lift it, knife however is for cutting and slicing.
Materials
Cutlery is normally made with stainless steel or sterling silver. Silver sterling is used because
pure silver is soft, and it is hard to mould and shape. Silver may also tarnish whereas it will react
with air and will have a dirty look. Sterling silver however is an alloy of 92.5% silver and 7.5%
of zinc and copper. Sterling silver is more durable and stronger along with it being cheaper than
pure silver.
Stainless steel however requires more extensive processes to make. These steps include:
1. Melting the Raw Materials
Nickel, iron ore, chromium and silicon are placed in a furnace and heated to approximately 10
hours to form stainless steel compound.
2. Removal of excess carbon
The molten stainless-steel compound is placed in a Vacuum oxygen decarburization system to
remove excess carbon. The amount of carbon removed may affect the strength of the stainless
steel.
55
Material Selection
Material Science
Group Assignment
3. Tuning
The molten compound is stirred to ensure the components are evenly distributed it as well helps
to separate impurities.
4. Forming
While the compound is being cooled a hot roll is used to make blooms and billets which can be
accurately designed using cold rolling.
5. Annealing
This is a step in softening the metal as well as relieving internal stress of the steel. Age hardening
may be used
6. Descaling
In the annealing step it may cause a build-up of steel to be formed. Pickling or electro-cleaning
may be used to descale the metal however pickling is the most common method. Pickling
involves the use of nitric hydrofluoric acid whereas the metal is placed in the solution.
7. Cutting
The stainless steel is then cut with machinery to the desired shape and dimensions
8. Finishing
Stainless steel is cleaned, buffed, and polished to improve corrosion resistance. Abrasive
substances are used to clean the stainless steel and grinding wheel are used to grind the edge of
the steel. (Marlin Steel, 2020)
Manufacturing Process
• Rolling
First step is to set out the stainless, silver or flatware whereas large rolls are stamped that are flat
piece. The pieces are cut in small and they are made to the proper thickness and close to the
shape that is trying to be made. This shape and thickness are achieved by rolling, it is rolled to its
desired width first then to its length. The rolling process is carried out by a machine. (Webster,
2017)
• Annealing
The metal is heated using ovens to soften the metal.
• Cutting
The heated metal is then cut to correct shape of the cutlery being created. The excess metal is
heated to be used again.
56
Material Selection
Material Science
Group Assignment
• Patterning
A die is used to create the patterns, it uses two dies, one at the front and one at the back. The
piece of metal is placed in the die and a press of high pressure is used to form the pattern of the
Cutlery part. The press improves the hardness of the Cutlery parts. Some utensils require unique
manufacturing steps. For knives, the handle is made using two metals and bonds them with
soldering tools. Forks require a different cutting whereas it has tines however it is press like
normal. Spoons are made using a specific type of drop hammer or press to achieve the scoop in
the spoon.
• Silver-Plating
Some may require silver coating by the
process of electrolysis. The metal is
cleaned first then electrolysis take place
whereas silver is deposited on the metal.
• Buffing
Buffing is smoothing and polishing the
cutlery. It is important for the ends of the
handles may still be sharp from cutting. It
is use to give the cutlery parts a shiny
look. (How Products are Made, n.d.)
(Webster, 2017)
Performance Criteria
Important criteria are:
1.
2.
3.
4.
Availability
Corrosion Resistance
Safety
Heat Resistance
Availability is important whereas cutlery parts are used in everyday life therefore stainless steel
must be a material that is easily accessible.
Corrosion resistance is important for it is not safe to have handling food with rusty cutlery parts.
Safety is important where some metals is poisonous therefore the material use must be safe to
place in the mouth of the user.
Heat resistance is important whereas the cutlery parts may be exposed to high temperatures there
it would be sufficient for it to maintain its physical property after it being exposed.
57
Material Selection
Material Science
Group Assignment
Property control method
To prevent corrosion pure silver can be used to coat the product through the process of
electrolysis. The coating will prevent the more susceptible metal from being oxidized whereas a
less reactive metal is use for coating. Safety can be improved by using less poisonous metal or
metal that will not leave a taste in your mouth.
58
Material Selection
Material Science
Group Assignment
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