Process planning and cost estimation unit 1

1. ME8793 - PROCESS PLANNING AND COST
ESTIMATION
D. SAKTHIMURUGAN, M.E., (Ph.D)
AP/ MECHANICAL ENGINEERING
EASWARI ENGINEERING COLLEGE
RAMAPURAM, CHENNAI – 89.
Mail: sakthimurugan.d@eec.srmrmp.edu.in
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2. The 21st century engineering response to world
competition is concurrent engineering
Concurrent engineering requires the integration of
all aspects of the product life cycle, that is:
➢ Design,
➢Manufacturing,
➢Assembly,
➢Distribution,
➢Service,
➢Disposal.
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3. ➢Two important areas in the life cycle of a
product are design and manufacturing.
Process planning serves as an integration link
between design and manufacturing.
DESIGN
PROCESS
PLANNING
MANUFACTURING
INSPECTION
Design
Modification
Process
Improvement
Process
Problem
DESIGN & MANUFACTURING INTERFACE
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4. PROCESS PLANNING
➢An act of preparing a detailed processing
documentation for the manufacture of a piece
part or assembly.
➢Systematic determination of the methods by
which a product is to be manufactured in
economically and competitively.
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5. PROCESS PLANNING VS PRODUCTION
PLANNING
➢ Process planning is concerned with the Engg and
technological issues of how to make the product and
its parts. what type of equipment and tooling are
required to fabricate the parts and assemble the
product.
➢ Production Planning is concerned with the logistics
issues of making the product. i.e. ordering the
materials and obtaining the resources required to
make the product in sufficient quantities to satisfy
demand for it.
➢ It may be noted that always production is done only
after the process planning.
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6. ME8793 - PROCESS PLANNING AND COST
ESTIMATION
OBJECTIVE:
To introduce the process concepts to make
cost estimation for a various products after
process planning.
UNITS:
1. Introduction to process planning
2. Process planning activities
3. Introduction to cost estimation
4. Production cost estimation
5. Machining time calculation
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7. UNIT I- INTRODUCTION TO PROCESS PLNNING
What is Process Planning (or) Operations Planning?
Process planning is the systematic determination of the engineering
processes and system to manufacture a product competitively and
economically.
➢ Methods of process planning
➢ Drawing interpretation
➢ Material evaluation
➢ Steps in process selection
➢ Production equipment and tooling selection.
What are information required to do process planning?
➢ Quantity and quality of the product
➢ Specification of the product
➢ Availability of machine, tools, workers.
➢ Operation time
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8. EXAMPLE: PROCESS PLAN
(ROUTE SHEET OR OPERATION SHEET)
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9. METHODS OF PROCESS PLANNING
PROCESS PLANNING
MANUAL PROCESS
PLANNING
WORKBOOK
APPROACH
TRADITIONAL
APPROACH
COMPUTER AIDED
PROCESS PLANNING
RETRIEVAL
CAPP
GENERATIVE
CAPP
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10. MANUAL PROCESS PLANNING
➢ The process plans is prepared manually.
➢ It involves examination and interpretation of the working
drawing, making decision on process equipment section etc.,
➢ Therefore manual process planning very much depended
on the cost.
➢ It is suitable for small scale industries.
ADVANTAGES
➢ Most suitable for small scale industries
➢ This method is highly flexible
➢ It requires low investment costs
➢ It has few steps to produce the component
DISADVANTAGES
➢ Time consuming and complex
➢ It requires large amount of data
➢ Requires skilled operator
➢ It leads to human error
➢ It increases paper work
➢ It may reduce productivity
➢ Not suitable for mass production
Specification of the product
Design of the product
Part Drawing Specification
Product Analysis
Process Selection
Selection of tools, work
holding devices inspection
methods
Selection of parameters like
feed, depth of cut etc,.
Implementation
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11. PRODUCT ANALYSIS
(MAKE OR BUY DECISION - EXAMPLE)
Problem: 2500 components are required for an assembly line. This
component is available at the rate of rupees 4 per piece in the local
market. If the same components to be manufactured in the factory
itself, the fixed cost will be rupees 2500 and the variable cost will be
rupees 2 per piece. Decide whether to make or buy.
Given data:
Quantity (N) = 2500
Selling price of component (P) = 4 per piece
Fixed cost (F) = 2500 Variable cost (V) = 2 per piece
Formula Used:
➢ Cost of Making Total cost = F+NV = 2500+(2500x2) = 7500
➢ Cost of Buying Total cost = NP = (2500x4) = 10,000
Conclusion: Cost of making the product is the less amount as
compared to cost of buying so the component should be made.
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12. COMPUTER AIDED PROCESS PLANNING ( CAPP)
➢ In order to overcome the drawbacks of manual process planning the
computer aided process planning is used.
➢ With the use of computer process plan is made.
➢ It can reduce routine clerical work. So that the productivity increases.
COMPARISION BETWEEN MANUAL AND CAPP
MANUAL PROCESS PLANNING CAPP
It is prepared manually It is prepared by computer
It is suitable for small scale industries It is suitable for mass production
Complex method and more time consuming Simple method and less time
Possible for human error Error can be minimized
This method requires more skill operators This method requires less skill operators
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13. RETRIVAL OR VARIENT CAPP
➢ A retrieval CAPP system is based on the principles
of group technology, part classification and coding.
➢ In this system each part family a standard process
plan is prepared and stored in the computer.
➢ Code number is generated by the classification
and coding.
➢ These codes are used to identify the part family
and the associated standard process plan.
➢ The standard plan is edited for the new part.
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14. Advantages of the retrieval CAPP system Disadvantages of the retrieval CAPP
system
The standard process plan has been
written. By using the standard process
plan a variety of parts can be planned.
The components to be planned are
limited to similar components previously
planned.
Simple programming and the installation
is required to implement a planning
system
The system is understandable and the
planner has control the final plan
Experienced process planners are
required to modify the standard plan for
the specific components.
It is easy to learn and easy to use
GENERATIVE CAPP SYSTEM
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15. GENERATIVE CAPP SYSTEM CONT…
➢ Generative CAPP generates the process plan based on decision
logics and the pre coded algorithms.
➢ The computer is used to generate individual process plan
automatically.
➢ When using a system, a specific process plan for a specific part can
be generated without any involvement of a process planner.
➢ Human role is inputting the GT code of the given part and
monitoring the function
ADVANTAGES:
It can generate process plan rapidly.
New components can be planned easily.
It has potential for integrated automated manufacturing facility.
DISADVANTAGES:
The generative approach is complicated and very difficult to develop.
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16. DRAWING INTERPRETATION
Aim and Objectives
➢ Identify appropriate supplementary information
from the drawing to aid the process.
➢ Identify and interpret dimensional and geometric
information from the drawing .
➢ Identify the critical process factors for the
component from the dimensional and geometric
information from the drawing.
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17. TYPES OF DRAWING
Detail drawing
➢Single part drawing
➢Collective drawling
Assembly drawing
➢Single assembly drawing
➢Collective assembly drawing
Combined drawing
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19. MATERIAL EVALUATION
AIM & OBJECTIVES
➢ Identify and specify common material used for
manufacture.
➢ Identify and specify the main properties of the material.
➢ Identify and specify the common material selection
process.
➢ Identify and specify the common process used for
manufacture.
➢ Carryout an overall evaluation of the selection of materials
for manufacture in terms of processes.
➢ Select the suitable process for given product based on
critical processing factors identified during the drawing
interpretation.
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20. MATERIAL EVALUATION
(TYPES OF MATERIAL)
ENGG. MATERIALS
METALS COMPOSITES CERAMICS PLASTICS
FERROUS
NON
FERROUS
AMORPHOUS
THERMOSETS
THERMO
PLASTICS
ELASTOMERS
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21. MATERIAL EVALUATION
(MATERIAL PROPERTIES)
Mechanical properties
➢ Density
➢ Strength
➢ Hardness
➢ Ductility
➢ Toughness
➢ Fatigue resistance
➢ Creep
Chemical properties
➢ Reactivity
➢ Combustibility
Thermal properties
➢ Thermal conductivity
➢ Coefficient of expansion
➢ Melting point
Electrical properties
➢ Conductivity
Optical properties
➢ Transmissivity
➢ Colour
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23. PROCESS SELECTION
Definition
Process selection is defined as the way the company chooses to
produce its products. It determines how the product will be
produced.
What are all the choices involved in process selection? (or)
Explain the Procedure for process selection
It involves
1. Technological Choice
a. Major Technological Choice
b. Minor Technological Choice
2. Specific Component Choice
3. Process flow Choice
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24. 1. Technological Choice
a. Major Technological Choice
Question technology is used to take the decision about the major
technological choice. They are
➢ Does technology exists to make the product?
➢ Should the technology be developed in the country?
➢ Should innovations be licensed from foreign countries?
b. Minor Technological Choice
After selecting the major technology for the manufacture of product,
the following minor technological choices are to be made.
➢ Whether the process can be done continuously for 24 hrs a day like
steel (or) chemical industries?
➢ Whether the manufacturing can be done on a job-shop process?
➢ Whether manufacturing can be done in an assembly line?
➢ Selecting a suitable basic process for the manufacturing of the
product among the various alternatives.
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25. 2. Specific Component Choice
when the manufacturing process is determined the specific machine or
equipment to be used is to be selected. The following factors are analyzed before
selecting the correct machine or equipment.
➢ Degree of automation required .
➢ What type of equipment should be used?
➢ Whether single purpose, special purpose of general purpose machine is to be
used?
➢ What are the activities to be done by the operator and what activities are to be
done by the automatic means?
3. Process Flow Choice
➢ How should the product flow through the operations systems?
➢ The final process selection step determines how materials and products will move
through the system.
➢ Assembly drawing, assembly charts, route sheets are used to analyze the process
flow.
➢ Analysis may lead to re sequencing or eliminating operations in order to reduce
material handling and storage.
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26. DETERMINATION OF MAN, MACHINE AND
MATERIAL REQUIREMENT
• During the process selection we should consider the following
a) Determination of man requirement
b) Determination of machine requirement
c) Determination of material requirement
Determination of Man Requirement:-
If worker works for one hour it is called as one man hour. In general one day means eight
hour.
In the process selection it plays an important role. It is necessary to calculate
No of man hours required for available work =H1
No of man hours required for new work =H2
No of man hrs for allowance like leave, absent =H3
Total man hrs available =H4
Additional man hrs required =(H1 + H2 + H3) - H4
No of additional men required = (H1+H2+H3)-H4 / 2000
(Assume 2000 man hrs per man per year)
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27. Determination of Machine Requirement:-
The requirement of machinery is calculated as follows
No of machine hours required for available work =H1
No of machine hours required for new work =H2
No of machine hrs for allowance like machine setting maintenance
power off =H3
No of machines required N1 = (H1+H2+H3) / 2000
(Assume 2000 machine hrs per machine per year)
Available machines = N2
Additional machines required = N1-N2
Determination of material requirements:-
The selection of material depends on the types of material, shape
and size of the component. It should be right quality as per the
specifications. Shape and size of the material should reduce the
scrap
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28. Determination of Material Requirement:-
The requirement of material is calculated as
follows
Material requirement for available work =Q1
Material requirement for new work =Q2
Material available in store =Q3
Additional material to be purchased=(Q1+Q2)-Q3
The selection of jigs fixtures etc., will give
➢High production rate
➢Reduce cost of production
➢Minimize the setting time
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