Robotics Engineering
DoDEA - Career and Technical Education
Identifying Elements of Materials and
Structural Design
Exercise 2- Materials
Objective: At the completion of this exercise, you will demonstrate your knowledge of the properties of various
materials, how they are manufactured and then converted into the products we use.
Deliverables: Copy and paste the required deliverables to another document for submission. All deliverables
must be word processed with the required student ID information in the footer of the
document. The header of the document should contain the title of the assignment. Both
the question and answer must be included in the deliverable with the answers
highlighted. All work must be complete and accurate to receive credit.
1.
2.
3.
Detailed definitions for each of the terms found in the Nomenclature section.
Detailed answers to the queries listed in the Questions section.
Completed table from the Materials Lab.
Information: Closely examine the display that you’re reading this document
from. What is it made of? Undoubtedly, you’ll recognize a type of plastic, some
metal and perhaps glass. You may also notice a bit of paint here and there. Although
you cannot see inside the device, it’s pretty clear that this display was manufactured
from a variety of materials using processes that compress, stretch, mold, separate, fasten
and coat the component parts needed to construct it. Of course, this would be true for any modern product.
Identifying these materials, their characteristics and applications, as well as how they’re processed into a useable
forms allow us to understand how stuff is actually made.
Materials science is a field of study that applies the properties of matter to the areas of science and engineering.
Scientists that design new materials and discover their applications investigate the relationships between the
atomic structures within materials to better understand their properties and invent new materials.
Materials fall into the following broad categories:
 Biomaterials
 Ceramics
 Composite Materials
 Metals
 Polymers
 Semiconductors
Mechanical properties of materials include:
 Strength
 Elasticity
 Plasticity
 Hardness
 Toughness
 Fatigue
Normally, materials are first considered for their mechanical (or physical) properties. However, some materials
have other traits that could benefit or even interfere with a product’s manufacture or usefulness. Electrical
properties identify the degree of the material’s ability to conduct or oppose the flow of electricity. Optical
properties rate the materials ability to transmit light. Some materials are transparent while others are translucent
or opaque. Patterns in the material may also distort or diffuse light while pigment may be added to change the
color. Chemical properties determine how materials react with other materials. This includes oxidation or rusting.
Thermal properties determine how materials respond to forms of energy like heat and types of light. Researchers,
scientists and engineers must be knowledgeable of all these characteristics if they are to successfully design new
materials for the companies that make stuff.
Primary manufacturers process raw (natural) materials like wood, ore, minerals, natural gas and petroleum into
industrial materials also called standard stock. The company that built the display that you’re studying purchased
the standard stock like sheet metal, circuit boards, plastic graduals and semiconductors from primary
Robotics Engineering – DoDEA Career and Technical Education
Identifying Elements of Material and Structural Design – The History of Engineering
Revised 9 February 2016
manufactures. The display’s manufacturer processed the standard stock into the shapes and forms needed to
assemble and test the end product. The process of converting industrial stock into a finished product is called
secondary manufacturing and there are six methods involved in this process:
 Casting and Molding
 Separating
 Assembling
 Forming
 Conditioning
 Finishing
The materials and manufacturing industry is incredibly vast and
provides many opportunities for careers in Science, Technology,
Engineering and Math (STEM). For right now, let’s focus on just
one category of materials sometimes referred to as plastics.
We’ll determine the origins of plastic, its properties and its
manufacturing processes.
“I was trying to make something
really hard, but then I thought I
should make something really soft
instead, that could be molded into
different shapes. That was how I
came up with the first plastic. I called
it Bakelite.” Leo Baekeland - 1907
Plastic is a generic name sometimes given to a category of
materials more precisely known as polymers. The word
“polymer” is derived from the Greek word polumerēs, which
means consisting of many parts or segments. These segments
are actually replicating molecules called monomers (mono
means "one"). Polymerization is the process by which monomers react (combine) to form long chains that link to
other polymer chains forming the material we know as plastic. It’s these linkages and the molecular structure of
the polymer that determines the material’s properties. Polymers can be synthetic but are common in nature as
well. While hair, fingernails, feathers, cellulose, proteins, rubber and
starch are all naturally occurring polymers, synthetic polymers are
typically made from chemicals refined from petroleum oil.
Partially synthetic polymers (like gum elastic) have been around since
1832 but it wasn’t until 1907 that fully synthetic polymers made the scene.
Because plastic from synthetic polymers is easier and cheaper to
manufacture and much lighter than metal, the polymer industry has become
larger than the steel, aluminum and copper industries combined. In fact, polymers
have a range of uses that substantially surpass that of any other category of material.
Applications include adhesives, solvents, coatings, and foams. Packaging, textiles, industrial
fibers, composites, electronic devices, biomedical devices, and optical devices have also been
born from advances within this industry. Polymer research has also led to the spectacular
innovations in the emerging field of high-tech ceramics. Considering the impact, polymers have upon
modern life, it’s important to understand how plastic is produced and applied in the manufacturing process.
Robotics Engineering – DoDEA Career and Technical Education
Identifying Elements of Material and Structural Design – The History of Engineering
Revised 9 February 2016
Acrylonitrile (C3H3N)
Butadiene (C4H6)
Styrene (C8H8)
Let’s examine just one type of synthetic polymer in greater detail. It’s the familiar material that LEGO™ uses to
make all those plastic bricks, beams, plates and wheels. It’s a polymer commonly called ABS plastic which stands
for the three monomers used to construct the material; Acrylonitrile, Butadiene and Styrene. ABS is a
thermoplastic and its molecular formula is (C3H3N · C4H6 · C8H8)n That’s a lot of carbon, hydrogen and nitrogen
atoms to figure out how to put together. The diagrams above may provide a clearer understanding of the
molecular structure of the monomer components and how they might fit together to form the small polymer chain
of ABS plastic also shown above.
ABS plastic is a common thermoplastic used to make lightweight and rigid products such as pipe, musical
instruments, automotive body parts, helmets, and toys. Thermoplastic melts to liquid when heated and typically
hardens to a strong, glasslike material when it’s cooled. Polymers are broken down by breaking the intermolecular
bonds between them. This can be done by either heating the material or introducing other monomers (like
solvents) to substitute existing reactions in the material. The result is a reshaping or disintegration of the polymer
chains in the polymer material.
It’s all about how the monomer molecules are structured and how they react to produce polymer chains.
Engineers can choose the characteristics of the materials they develop by tweaking the monomers used to build
the material. The longer the polymer chains and increased intermolecular bonding between the chains… the
stronger the material becomes. Also, the closer the chains are packed together the more rigid the material
becomes. The polymerization of Acrylonitrile, Butadiene and Styrene creates a tough and safe material suitable
not just for LEGO™ but for many consumer products we use today. Heated thermoplastic can be blow and
vacuum formed, extruded, as well as injection, thermo-set, compression, insert, and transfer molded into a wide
variety of objects that serve a multitude of applications.
Research Resources: The www changes all the time. If you find a dead link, please report it to your
instructor but you should also use a search engine to find the information in another site.
Web Site
Description
http://science.howstuffworks.com/plastic.htm
How Stuff Works - How Plastics Work
http://entertainment.howstuffworks.com/lego.htm
How LEGO™ Bricks Work
http://www.youtube.com
YouTube - How do they do it? LEGO
http://www-materials.eng.cam.ac.uk/mpsite/default.html
Univ. Cambridge - Materials Selection and Processing
http://pslc.ws/
PSLC - Polymer Science Learning Center
http://www.pbs.org/wgbh/buildingbig/lab/index.html
PBS - Information about force/load upon materials/shapes.
See Instructor for Document
ITEA – HITS Manufacturing Processes
http://www.materialsworldmodules.org/modules/polymers.shtml
Materials World Modules - Polymers Module
http://www.wolframalpha.com/
Wolfram Research - Computational Knowledge Engine
http://www.sciencegeek.net/eChem/eChem.html
eChem - 3D Molecule Model Builder
Nomenclature: Research and develop a detailed (two to three sentences) definition for each of these terms.
It’s important to realize that many words have multiple definitions. Some of which may have nothing to do with this
course of study. Make sure your definitions fall within the context of this lesson.




Secondary manufacturing
Primary manufacturing
Industrial Stock
Casting/Molding Processes




Forming Processes
Separating Processes
Conditioning Processes
Assembling Processes
Robotics Engineering – DoDEA Career and Technical Education
Identifying Elements of Material and Structural Design – Materials
Revised 9 February 2016




Finishing Processes
Monomer
Polymerization
Composite Materials
Questions:
1. Partially synthetic polymers (gum elastic) have been around since 1832, but there wasn’t a strong interest to
move away from natural polymers until the 2nd World War. Why?
2. How would you categorize the mechanical properties of a pencil eraser?
3. How does the choice of materials affect the usefulness of an object?
4. Using terms from the Nomenclature section of this lesson… From nature to your book bag… Describe the
manufacturing process and life cycle of a pencil.
5. From the video, “How do they do it? LEGO™”… In 1999, when the video was produced our planet had 6 billion
people on it. At that time there were 62 bricks for every man, woman and child on Earth. Assuming the number
of bricks per person is the same… Calculate the approximate number of LEGO™ bricks that are on our planet
today. How many towers could you build to the Moon with that number of bricks?
Procedure: Materials Lab
In this activity, you’ll closely examine and then categorize various materials according to their mechanical
properties. Each sample that you’ll evaluate is identified with a number. Complete the table below rating each
material from 0 to 3 (3 being the highest) and identify the name and type for each material sample.
Required Materials and Equipment: Volt-Ohm-Milliammeter (Multimeter)
Get the following samples from your instructor:
1
1
2
1
1
2
 Aluminum
 Glass
 Plastic (Acrylic)
0
Opacity
Conductivity
Fatigue
Toughness
 Plywood
 Steel
 Cardboard
Hardness
Plasticity
Strength
Sample
ID #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
 Wood
 Fiberglass
 Cotton
Elasticity
 Particleboard
 Brass
 Rubber
3
Material Name
Cardboard
 Plastic (PVC)
 Ceramic
 Wax
Material Type
Biomaterial
Conclusion:
Our stuff is made from the raw materials harvested from our Earth’s natural resources. Primary manufacturers
convert these natural supplies into industrial materials or standard stock. Standard stock like sheet metal, thread,
wood, fibers, plastic granules, and other materials are purchased by secondary manufactures where it’s casted,
molded, formed, separated, conditioned, assembled and finished into the products we purchase from stores.
Knowing the characteristics of these materials, how they’re produced and processed helps engineers realize the
limitations
of
materials
as
they
design
solutions
to
modern
engineering
problems.
Robotics Engineering – DoDEA Career and Technical Education
Identifying Elements of Material and Structural Design – Materials
Revised 9 February 2016
Robotics Engineering – DoDEA Career and Technical Education
Identifying Elements of Material and Structural Design – Materials
Revised 9 February 2016