E-MOBILITY SPRINT MODULE – MANUFACTURING PROCESSES
MANUFACTURING ENGINEERING – AN OVERVIEW
1.DEFINITION, NEED AND SEQUENTIAL ACTIVITIES
2. PROCESS PLANNING
3. INDUSTRIAL ENGINEERING (Pertaining to
Manufacturing)
4.LAYOUT ENGINEERING
5. MATERIAL HANDLING
1.DEFINITION, NEED & SEQUENTIAL ACTIVITIES
WHAT IS MANUFACTURING ENGINEERING (ME)?
1.1. A CONTEXTUAL DEFINITION:
ME is the process of planning, designing & creation of all
Infrastructural, Manufacturing & Support Facilities involving
efficient utilization of all resources, to meet the desired
output and quality of a single/range of similar/dissimilar
products.
Also includes periodic upgradation of technologies to
enhance the capacity of the facility, quality of Products and
reduction of manufacturing costs.
1.2. NEED:
To develop technically and commercially viable alternatives
for the manufacturing and support processes, facilitating
their evaluation and selection for execution.
This entails deployment of personnel with executable
knowledge in various disciplines of engineering, exploiting
Computer- based technologies and visualization by way of
‘Walk- Through Animations’, Simulations etc., of the
manufacturing lines, to identify issues well beforehand and
their resolution, prior to any asset related financial
commitments.
Also enables creation of facilities which are well integrated.
1.3. SCOPE:
All In-House Manufacturing and Support activities
1.4. ME - SEQUENTIAL ACTIVITIES:
We will look at the steps involved in setting up a new
Manufacturing Facility for a complex product consisting of a
large number of parts & sub- Assemblies.
Basis for the ME exercise is the 5 or 10-year Demand
Forecast for the product by Business - Planning/Marketing
functions.
The steps generally involved are:
 Provide estimate of area, investments and
corresponding plant capacities for feasibility and
approval.
 Provide inputs for location and site selection.
 Identify In-House manufacturing activities through ‘Make
or Buy’ exercise.
 Complete Process Planning and Layout plans for all Inhouse activities and provide inputs for site development,
buildings and related civil infrastructure plans.
 Prepare list of all manufacturing & support facilities
including Material Handling, Buildings & civil
Infrastructure, utilities.
 Assign values for all items and prepare a Financial
Budget and time frame for completion.
 Obtain formal approval.
 Procurement (or aid in procurement) of all items and
construction of buildings & related infrastructure.
 Completion of all Buildings & related infrastructure
enabling installation of plant & machinery.
 Installation and commissioning of all plant & machinery.
 Start of Manufacture.
We will look at some of the following constituents of ME in
greater detail:
1. Process Planning
2. Industrial engineering (Pertaining to Manufacturing)
3. Layout Engineering
4. Material Handling
It is very important to note that none of the above is a totally
independent activity or a clearly preceding or succeeding
activity in relation to another.
They are interlinked and concurrent activities with outputs
from one serving to modify other activities, prior to start of
manufacturing.
Whenever any change or modification is done in one,
corresponding influences in others, are to be studied and
validated.
As such, the benefit of ME depends on the proper integration
above set of activities as a whole.
We will also be looking at technological advances in some of
the above activities.
2. PROCESS PLANNING
Process Planning is the development of a manufacturing
plan, defining the sequential operations and the plant &
machinery required for the manufacturing processes.
It is an essential intermediate activity between the design
of a product and its physical manufacture.
Process planning translates product design specifications
into manufacturing process details.
2.1. NEED:
 Enables manufacture of interchangeable parts.
 Forms the basis for Control Plans for Quality control.
 Provides routing information for Production control.
 Identification of machines, equipment, tooling etc.,
required for the manufacture of the part/product.
2.2. Preliminary Process Planning Procedure:
 Decide the start and finish condition of the product in
the manufacturing line.
For e.g., ‘Casting’ as the starting and ‘Fully machined
part’ as the finishing condition, in a Machining Line for
the part.
 Define the sequential steps of operations to be
performed.
 For each one of the operations, define the machine,
tooling, equipment, gauges etc., required.
2.3. Final Process Planning Procedure
 Estimate the Cycle time (start to end of an operation).
 Increase or decrease the number of operational steps
to match the ‘Takt Time’ as given by Industrial
Engineering.
 For each one of the finalized operations, define the
machine, tooling, equipment, gauges etc., required.
 identification/creation of datum surface, location and
clamping of the part during the manufacturing
operation to facilitate design of Jigs & Fixtures.
3. INDUSTRIAL ENGINEERING (IE)
IE is associated with achievement of an organization’s
objectives with optimum utilization of all resources
Generally, IE is an all- encompassing and ongoing activity
aimed at Setting up standards, Measuring and Improving the
efficiency of all types of business processes.
However, we will be looking at only those aspects of IE
 Related to Manufacturing and it’s supporting processes
at the time of Planning the Manufacture of the
product.
 As such, the required quantification is based on scientific
estimation and not through actual measurements.
NEED:
Establishment of standards through scientific methodologies
enables, ease of acceptance by all concerned.
These standards form the basis for comparison and selection
of suitable alternatives.




Topics of Interest:
Estimations/Measurements terminologies & Methods
Capacity Planning
Manpower Planning
Identification of type of Manufacture & Layout
3.1 ESTIMATIONS/MEASUREMENTS TERMINOLOGIES & METHODS
3.1.1- Terminologies
 Takt time (TT): The pace of producing units at a
rate/frequency that meets projected/customer demand.
Takt Time ‘TT’ = (Available Time) / (Customer Demand
in Units).
Available time is the time available to build a Product
and excludes time spent on Breaks, Changeover or
Maintenance.
For example, if workers are available for 7.5 hours or
450 minutes in a shift of 8 hrs and the customer wants
150 units to be produced in a shift, then the
Takt Time ‘TT’= 450 /150 = 3 Minutes per Unit.
 Estimated Cycle Time (ECT)
Cycle time is the elapsed time from the start of a
process until it is completed.
At the planning stage, the cycle time is estimated and
ECT = Machine/Equipment Duration + Manual task
Duration, of a process.
In a Manufacturing line with a number of
stages/stations, the ECT is estimated for each station.
During trial Production runs and actual production, ECT
is refined further to reflect actuals through
measurements to get Actual Cycle time.
 Control Cycle Time of a Manufacturing line (CCT)
‘CCT’ is the EST for the longest operation, which
cannot be split up further into smaller operations, in the
line.
 Line Output = Available production time/CCT
To meet the Customer demand, ‘CCT’ should be less
than ‘TT’.

Total Work Content (TWC): It is the duration of time
passed, to get a product through the entire production
processes in a Manufacturing Line.
TWC = Sum of ESTs of all the work stations of a Line
TWC will be an indication of the manufacturing lead time
required to complete all the processes in a particular
manufacturing line.
 Minimum No of stations required in a line
S MIN = (TWC) / (CCT)
3.1.2. Methods
IE is involved in planning the output from each and every
manufacturing line which will match or will be capable of
exceeding the demand for the product, as defined by the
Takt Time ‘TT’.
The steps followed are:


Determination of Takt Time
Estimation of the ECT for all the stations
The time duration for any process in a line consists
of Machine/Equipment times + Manual Operations
required in that station, unless the process is totally
automated.
The estimation of Machine/equipment occupation for
the process is based on available standards and the
Process Planning sheet.
The duration of machine occupation for a machining
process for e.g., is estimated based on cutting
speed standards, length, depth of cut etc., The
Manual content for that process for e.g., may involve
loading and loading of the component and operating
the machine controls (assuming the machine is
manually controlled) is estimated.
For the manual content estimation, the preferred
option is the Predetermined Motion Time System
(PMTS) methodology to set the standard time in
which a worker should perform a task. (the original
and more sophisticated Methods Time
Measurement technique, better known as MTM, is a
global standard).
Maynard operation sequence technique (MOST), is
a proprietary Software based PMTS used in India. A
manual task is broken down into individual motion
elements, and each is assigned a numerical time
value in units known as Time Measurement Units, or
TMUs, where 100,000 TMUs is equivalent to one
hour. All the motion element times are then added
together and any allowances are added, and the
result is the standard time.
The Estimated Cycle Time (ECT) is then the sum of
Machine/Equipment time + Manual Task Time for
the process.
In an ideal situation, the ECT for each one of the
stations in the line should be more or less the
same. In practice however this will not be the case.
A preliminary Line balancing exercise is done to
equalize the ECT to the extent possible. A
reallocation of operations from one station to
another, refining the number of stations, machines
for the lines to achieve equalization of ECT. In most
cases, the station with the highest investment
machine will have the longest ECT which will be the
CCT station of the line.
3.2. CAPACITY PLANNING
Basis for the Capacity Planning is the year- wise
Forecast/Projected demand for the product for a duration of
the next 5 to 10 years, given by Marketing/Business Planning
functions. It is generally expressed as Number of Units per
Annum.
Depending on the Complexity of the Product, extent of InHouse Operations, Investments thereof and the uncertainties
associated with the Demand Projection, the capacity build-up
can be a one- shot exercise or done in a phased manner.
In a phased build-up, a single shift operation (of 8 hours
duration each) is planned initially. Increase in the number of
shift operation is taken up in the next phase with
corresponding increase in Manpower.
Further increase in capacity will be through installation of
additional manufacturing and support facilities to achieve the
demand projections.
The Planned Capacity should always be based on the
Control Cycle time ‘CCT’ of the Main Manufacturing Line and
not by the ‘CCT’ of any branch line of the Manufacturing Unit.
However, in case the Branch line outputs need to cater to
Spare parts and after market requirements, then their
capacities may exceed that of the Main Line.
3.3. Manpower Planning
Corresponding to the Capacity Build up plan, the requirement
of ‘Blue Collar’ and ‘White Collar’ categories of Manpower is
estimated.
Blue Collar category refers to Workmen on the shop floor
either directly engaged in Manufacturing or indirectly
engaged in the Support Activities (Viz., Material Handling,
Inspection, Stores, Packing & Dispatch etc.,).
White Collar refers to the Staff required in various Offices and
also the Executive and Managerial personnel for the
Manufacturing Lines and Offices.
Direct labor estimate is based on the Manual portion of the
TWC for the various lines. The Indirect Labor content
estimated by the Number of Inspection stations to be
manned, Material Handling Equipment (Fork Lift Trucks,
Trollies etc.,) to be operated etc., It generally a percentage of
the direct labor numbers depending on the type of industry.
Manpower Estimates provide inputs for:
1. Cost of Manpower (for Project Evaluation, Product
Pricing Etc.,)
2. Facility assessments for Locker Room, Canteen, Wash
Rooms, Drinking Water, Domestic Effluent Treatment
etc.,
3.4. Recommendation on Type of Manufacture & Layout
Based on the estimated data available and from the
optimum utilization of resources (Area, Buildings, Plant &
Machinery, Manpower etc.,) point of view, IE can
recommend the type of Manufacture to be adopted and the
Layout for the different Manufacturing Lines of the Plant.
It is quite possible that within the same Plant different
types Manufacture in terms of Batch, Continuous etc., can
be recommended for different Manufacturing lines.
Types of Manufacturing are Job shop, Batch
Manufacturing and Mass manufacturing.
Job shop consists of General -Purpose Machinery and run
on Made to Order basis of small number of different parts.
Batch Production uses general purpose or flexible
machinery and batch quantity of one product is taken up
after completion of batch production of previous product.
Change over involves tooling set-ups.
Mass Production uses dedicated or special purpose
machinery for a single product or a family of similar
products.
From the layout point of view, it could be Process, Product
or Cellular layout etc.,
These recommendations serve as vital Inputs to the Layout
Engineering and Material Handling Exercises (dealt in
detail later), to be done as part of ‘ME’.
4. LAYOUT ENGINEERING
4.1. Definition
Layout Engineering or Plant Layout as it is called deals
with Planning the systematic arrangement of:
 Manufacturing Shops and other Buildings within the
site, the connecting roads, drains etc., in the Site
Layout.
Typical Site Plan Drawing
 Manufacturing Lines, Storage areas etc., within a
Shop Building in the Shop Layout.
Typical Shop Layout Drawing – Plan View
 Machines and equipment within a Manufacturing Line
in the Line Layout or a Block Layout.
 Coordinates of each and every machine & Equipment
of a line with reference to the Building Columns of the
shop, in the Installation Layout.
4.2. Need
 Layout engineering ensures efficient use of internals of all
covered areas.
 Defines the connectivity between buildings.
 The flow of all direct and indirect materials required for
the Manufacture of the Product and its dispatch to
Customers.
 Identifies the Roads, Drains, Landscaped areas etc.,
within the site.
 Forms the basis for site development (defining the
elevations of areas of the site) and Material Handling
designs.
4.3. Types of Basic ‘Line Layouts’
The three basic type of layouts are:
 Process Layout
 Product layout
 Fixed Position layout
4.3.1. Process Layout
Process layout clubs together all similar process
machines/equipment and the processed parts move from one
process area to another for completion.
Process layout is generally adopted for High Variety Low
Volume Products where the low offtake of a product cannot
justify dedicated Machine/s and a shared Machines facility is
the preferred method.
Process layouts are found primarily in job shops, or firms that
produce customized, low-volume products that may require
different processing requirements and sequences of
operations.
A Process Layout in Manufacturing
Characteristics of a Process layout are:








Intermittent Operations
General Purpose Machines/Equipment
Machines Set-up time for Tooling Change
Storage space for High In-Process Inventory
Flexibility to handle variety
Low Efficiency
Made to order batch production
Low Finished Goods Inventory
A Metal Stamping Factory – Process Layout.
4.3.2. Product Layout
For stable high-volume demand & low variety products, a
Product Layout is the Preferred option where dedicated
machines/equipment for each part can be justified.
The machines/equipment are arranged in series and in
sequence of the processes as defined in the Process Planning
document.
An Assembly line for Automotive Products is a typical example
of Product Layout.
A Product Layout
High volume demand requires a streamlined flow of materials
during the manufacturing process, a steady and balanced
output from the manufacturing lines.
An Electronic Assembly Line – Product Layout.
PART - A
PART - B
DRILLING
PLANING
MILLING
TURNING
GRINDING
GRINDING
ASSEMBLY & TESTING
FINISHED GOODS RECEIPT &
STORAGE
MATL RECEIPT & STORAGE
Product Layout – Machining & Assembly Shop
Characteristics of Product Layouts:








Streamlined unidirectional material flow
Standardized & Repetitive operations
Special Purpose Machines/Equipment & Automation
Low In-Process Inventory
Low Flexibility
High Efficiency
Balanced Work Stations
Any weak Link will affect reliability of the line
A Comparison of Product & Process Layouts
4.3.3. Fixed Position Layout
In this Layout, Product remains stationery while it is being built.
Equipment, workers, materials, and other resources are
brought to the Build station.
Adopted for building Commercial aircrafts, Ships, Very Large
& Heavy Earth Moving equipment etc., which are heavy and
bulky to move.
The size and complexity of Aircraft production requires a Fixed
-Position Layout. Construction takes place in stages at Fixed
Locations.
4.4. Types of Hybrid Layouts.
Hybrid layouts modify and/or combine some aspects of
product and process layouts.
The three Hybrid Layouts are:
 Cellular Layouts
 Flexible Manufacturing systems
 Mixed Model Assembly Lines
4.4.1. Cellular Layouts
Cellular layouts attempt to combine the flexibility of a
process layout with the efficiency of a product layout.
Based on the concept of group technology (GT), dissimilar
machines are grouped into work centres, called cells, to
process parts with similar shapes or processing
requirements.
Figure below shows a family of parts with similar shapes.
The cells are arranged in relation to each other so that
material movement is minimized. Large machines that
cannot be split among cells are located near to the cells
that use them, that is, at their point of use.
Cellular manufacturing is appropriate for medium levels of
product variety and volume. The formation of part families and
the allocation of machines to cells is not always an easy task.
Part families identified for design purposes may not be
appropriate for manufacturing purposes.
A Family Of Similar Parts
Revised Layout with 3 Cells
Cell 1 will be for parts A, D& F Cell 2 for parts C & G and Cell
3 for parts B, H, & E. In the three cells each part will be
produced in batches and tooling set up changes will be
required for the changeover.
The U-shaped Cells 1 & 3 are very popular with a single or
more operators going around manning all the cell machines
and a common aisle for supplying the raw material and
clearing the finished part.
4.4.2.
Flexible Manufacturing Systems (FMS)
FMS originally proposed for manufacturing similar set of
parts and consisted of fair number of automated machines
and handling systems. They could operate 24 hours a day
without manual intervention under computer control
involving complex software. As such they were prohibitively
expensive.
Currently, the trend in flexible manufacturing is toward
smaller versions of the traditional FMS, sometimes called
flexible manufacturing cells. It is not unusual in today's
terminology for two or more CNC machines to be
considered a flexible cell and two or more cells, an FMS.
Alternative FMS Layouts
4.4.3. Mixed Model Assembly Lines
Traditional lines designed for a group of similar products
with different cycle times were not efficient. A batch run
of products was done involving assembly of one product
and then a changeover to the next. This method was not
responsive to changing customer demands.
To be more responsive and efficient the manner in which
the assembly line was laid out was changed and operated
so that it really became a mixed model assembly line.
The time needed to change over the line to produce
different models was reduced. The workers were trained to
perform a variety of tasks and allowed them to work at
more than one workstation on the line, as needed. The way
in which the line was arranged and scheduled was also
changed.
The following factors are important in the design and
operation of mixed-model assembly lines:
· Line balancing: In a mixed-model line, the time to
complete a task can vary from model to model. Instead of
using the completion times from one model to balance the
line, a distribution of possible completion times from the
array of models must be considered. In most cases, the
expected value, or average, times are used in the
balancing procedure. Otherwise, mixed-model lines are
balanced in much the same way as single-model lines.
 U-shaped lines. To compensate for the different work
requirements of assembling different models, it is
necessary to have a flexible workforce and to arrange
the line so that workers can assist one another as
needed.
Figure below shows how the efficiency of an assembly
line can be improved when a U-shaped line is used.
A flexible and cooperative workforce and Product Model
Sequencing (Based on work content) would facilitate the
efficiency of a Mixed Model Line.
5.0. MATERIAL HANDLING
5.1. Definition
Material Handling deals with the movement or flow of
materials ‘Before’, ‘During’ and ‘After’ a manufacturing
process.
It also deals with storage of materials in various conditions
viz., Raw Material, In-Process material and Finished
Goods, which act as a buffer between Supply and demand
ensuring their uninterrupted availability.
5.2. Need
Material Handling connects the various stages of product
manufacture and thus forms an essential element of the
same and cannot be ignored as a ‘Non value addition’
activity.
Movement of material needs to be efficient as it utilizes
substantially the resources of Area and Manpower. It also
accounts for a significant portion of the Manufacturing
Costs.
Hence the need to examine whether any of these moves
can be eliminated, combined with some other moves or
simplified.
The movement & storage of materials should also ensure
that safety and quality aspects are not compromised.
5.3. Handling Systems Design
The diagram below shows the general approach to the
Handling systems design.
5.4. Handling Equipment – Categories
Three categories are
 Containers
 Material Transport Equipment &
 Storage & Retrieval Equipment
5.4.1. Containers.
Containers or Pallets enable standardized movement of
loose items of various shapes and sizes in bulk.
It is important to understand the concept of Unit Loads
associated commonly with containers/Pallets
The underlying principle of Unit Load is that, “it is quicker
and economical to move a lot of items at a time rather
to move each one of them individually”. The larger the
load handled, the lower the cost per unit handled.
Use of equipment and not manpower is required for
handling Unit Loads
Standard sizes of pallets are given below. Note the unused
floor space in a 40’ freight container for different pallets.
Wooden Pallets
Stackable Steel Box Pallets, normal and Foldable. Foldable
pallets occupy less space and preferred when empty
pallets are recirculated.
Parts of various shapes & sizes are contained in Box
Pallets.
5.4.2. Material Transport Equipment
Required to move material from one location to another
(e.g., between workplaces, between a loading dock and a
storage area, etc.) within a facility or at a site.
Important equipment are:
 Conveyors
 Industrial trucks
 Cranes
5.4.2.1 Conveyors
Conveyors are of different designs and uses. Common
types are belt, roller, motorized roller and overhead
conveyors. We categorize them as floor style (mounted on
the floor) or overhead.
Conveyors are used for:

Moving products from point A to B (to avoid wasted
time walking, or to reduce movements of forklifts, etc)

To carry products that are too heavy for manual lifting
and carrying.

To move a product while operators are working on it
(or adding to it). Like a final assembly conveyor at an
auto plant.

To avoid injury to workers from repetitive movement.
Or to prevent damage to products caused by
movement

To deliver products to a robot for processing. Or to
receive products from a robot that are ready for the
next step
Storage and buffering uses:

To store products between processes or at the final
process step

To create a buffer or accumulation bank. This is a
flexible storage system. Used where the quantity of
products in storage can be lower or higher as required
to balance process flow

To sequence or re-sequence products between
processes. Power and free systems can provide this.
Various types:
Belt Conveyor
Chain Conveyor
Gravity Roller Conveyor
Slat Conveyor
Overhead Conveyor
Overhead Power & Free Conveyor (Accumulation)
5.4.2.2. Industrial Vehicles/Trucks
Hand truck and hand cart Pallet Jack
Walkie Stacker
Forklift Truck
Pallet Truck
Platform Truck
Tractor -Trailer
Narrow Aisle Reach Truck
Automated Guided Vehicles (AGV)
Tow AGV
Unit Load AGV Assembly AGV
5.4.2.3. Cranes
Overhead Cranes are the preferred option for handling
bulky and heavy loads.
They operate above the operational area leaving it free.
Other floor- based handling systems can be used below
them at ground level.
They are reliable. Skilled operators and proper lifting
tackles are a must to ensure safety of the personnel
working under the crane area.
Overhead Travelling (OHT) or Bridge Cranes
BUILDING GIRDER
An overhead crane, often referred to as a bridge crane is
shaped like a moveable bridge. Bridge cranes are attached
to the interior structure of a building and are mounted onto
the girders that support the roof and walls of the building.
They are a permanent installation in factories and
warehouses and can lift extremely heavy objects.
Gantry Cranes
Gantry crane has an overhead bridge supported with it’s
own frame.
Gantry cranes are more flexible and versatile than bridge
cranes. They are completely self-sufficient and are
supported by their own A frames. Gantry cranes are
usually on wheels or mounted onto a track system. They
are far easier and quicker to assemble than bridge cranes
and can be easily moved outside and inside and from site
to site where required.
Jib Cranes
A jib crane is a type of overhead lifting device that’s often
used in a smaller work cell area for repetitive and unique
lifting tasks. Jib cranes are extremely versatile and can
also be paired with overhead bridge cranes to maximize
production.
5.4.3. Storage & Retrieval Equipment
Industrial product companies often operate to meet
forecast of demands as’ Made to Stock’ as against ‘made
to order’. They also need to deal with a variety of Product
models.
Buffer storage, also known as safety stock, is used
in manufacturing to temporarily store materials before
they move into another production process. It is also used
to store safety stock needed in the manufacturing process,
to deal with supply chain shortages, transportation delays
or unexpected surges in demands.
Buffer stocks facilitate rated product outputs, efficient
utilization of productive manpower & other resources
regardless of the above delays and fluctuations.
Open Yard Storage
Heavy and bulky Raw Materials which can tolerate
atmospheric exposure are stored in the open, served by
gantry crane.
Finished Goods waiting for shipment are also stored in the
open.
Storage of materials in Covered Areas
Bought out Finished (BOF)components, In-house parts
etc., are stored in covered areas. Depending on the size
and quantity of the parts, Pallet Racks, Bin Racks etc., are
used with appropriate Material Handling Equipment.
Pallet Racking System
Cantilever Racks (For Long items)
Line Side Storage of parts
CONCLUSION
An overview and basic concepts of Manufacturing
Engineering topics have been covered in the above pages.
Students are advised to do further studies in their areas of
interest to know more details.
Advances, mainly using Computer based capabilities will
be covered separately.