Dr. A. Asha Professor/Mechanical Engineering Kamaraj College of Engineering & Technology

1. UNIT II
PROCESS PLANNING
By
Dr. A. Asha
Professor/Mechanial Engineering
Kamaraj College of Engineering &
Technology

2. PROCESS PLANNING
 According to the American Society of
Tool and Manufacturing Engineers
“ Process Planning is the systematic
determination of the methods by which
a product is to be manufactured
economically and competitively”

3. OBJECTIVES
 To prepare a set of instructions that
describes how to manufacture the
product and its parts.
 To prepare a detailed specification
which lists the operations, tools and
facilities
 The prepare the functional
requirements of the product, quantity,
tools and equipment, and eventually
the cost for manufacture.

4. OVERALLDEVELOPMENTSOFPROCESSING
PLANS

5. PROCESS PLANNING ACTIVITIES
Analyze the Part Requirements
Determine the Operation
Sequence
Select the necessary
equipment
Calculate the Processing time
Document Process Planning
Communicate
Mfg. engr. Shop

6. ANALYSE FINISHED PART
REQUIREMENTS
 To analyze the finished part
requirements as specified in the
engineering design.
 The engineering design may be
shown as a drawing or CAD model
format.
 Based on the feature, dimensions and
tolerance specifications the
corresponding processing
requirements are identified.

7. DETERMINE THE OPERATING
SEQUENCE
 To determine the type of processing
operation that has the capability to
generate the various types of features
based on the tolerance.
 Two alternative ways of viewing the
decision
(a) As a conventional production shop,
material is removed or modified on the
rough part in stages in order to
convert it to the finished part

8. DETERMINE THE OPERATING
SEQUENCE
 (b) The reverse of the first case
Finished part Rough part
Here the material is added onto the
part.

9. SELECT MACHINE
 Economic considerations
 Production rate and unit cost of
production
 Durability and dependability
 Lower process rejection
 Minimum set up times
 Longer productive life of machines.
 Functional versatility

10. MATERIAL SELECTION
PROCEDURE
 Function : Material must perform in
terms of mechanical, physical,
electrical and thermal properties.
 Appearance : The aesthetic value of
the material must be considered.
 Reliability: Increasing consumer
demands for trouble free products
 Service Life : The length of the
service life over which a material
retains its characteristics.

11. MATERIAL SELECTION
PROCEDURE
 Environment : The material should
sustain the environmental conditions
whether it is beneficial or harmful.
 Compatibility: When more than one
material is used in a product or
assembly.
 Producibility : Material should be
able to be used for which it is intended
to
 Cost : The cost of the material should

12. CALCULATE PROCESSING
TIMES
 Calculate the set up times and cycle times.
 Set up time is calculated based on the
available tooling and sequence of steps.
 The processing time based on the
sequence of operations is calculated
 Part loading and part unloading time is
calculated.
 Standard cycle time = set up time +
processing time + part loading + Part
unloading + allowances
 Standard cost calculated for the given part

13. DOCUMENT PROCESS PLANNING

14. ROUTE SHEET
 Part identification
 Description of the processing steps in
each operation.
 Operation sequence and machines
 Standard set up time and cycle times
 Tooling requirements
 Production control information
showing the planning, lead time at
each operation.

15. REASONS FOR
DOCUMENTATION
 To have a record on how a part is
processed in order to plan future parts
with similar design requirements
 To provide a record for future job
quoting, cost estimating and standard
costing systems
 To act as a means for communication

16. COMMUNICATE
 Communicate the manufacturing
knowledge to the shop floor.
 To ensure that the route sheet is
followed properly.
 To maintain quality in manufacturing.

17. APPROACHES TO PROCESS
PLANNING
 MANUAL PROCESS PLANNING
 COMPUTER AIDED PROCESS
PLANNING (CAPP)
(a) Retrieval type
(b) Generative type

18. MANUAL PROCESS PLANNING
 Examining and interpreting the
drawings
 Making decisions on machining
process selection.
 Equipment selection, tools etc.
 Dependent on the skill and judgment
of the process planner.
 Different planners may produce
different process plans.

19. ADVANTAGES & DISADVANTAGES
ADVANTAGES :
 Used for small scale industries where there
only few processes involved.
 Highly flexible
 Low investment costs
DISADVANTAGES :
 Time consuming involving large amount of
data.
 Skilled process planner
 Human error
 Increases paper work
 Inconsistent process plans result in lower
productivity

20. CAPP
 Reduces routine clerical work
 Generates rational, consistent and
optimal plans
 Interfaces CAD and CAM.

21. RETRIEVAL CAPP

22. RETRIEVAL CAPP
 Idea behind retrieval CAPP is that
similar parts have similar process
plans.
 Based on the principle of group
technology.
 Parts classified and coding.
 For each part family a standard
process plan (route sheet) is prepared
and stored in computer.

23. RETRIEVAL CAPP
 Code number is generated for each
part family.
 When needed for a new part the
standard plans are retrieved and
edited for a new part.

24. ADVANTAGES& DISADVANTAGES
Advantages :
 Using a standard plan a variety of new
parts can be planned.
 Simple programming
 Easy to understand and implement.
 User friendly.
Disadvantages :
 Experienced process planners are
required to modify the standard plan.
(Multi CAPP, MIPLAN)
 The components to be planned are
limited in number

25. GENERATIVE CAPP
 Generates the process plans based
on the decision logic and pre coded
algorithms.
 The computer stores the rules of
manufacturing and equipment
capability.
 A Specific process plan for a specific
part can be generated without the
involvement of a process planner.
 The human role includes
(a) Input the GT codes for the part

26. COMPONENTS OF A GENERATIVE CAPP
 A part description : identifies series of
component characteristics, including
geometric features.
 Machining Parameters : To decide the
cutting parameters.
 Select and Sequence
individual operations : Decision logic
and Decision trees, algorithms are
used to calculate the sequence and
operation times

27. COMPONENTS OF A
GENERATIVE CAPP
 Data base : Available machines and
tooling
 Report Generator : Prepares the
process plan reports

28. ADVANTAGES &
DISADVANTAGES
 Advantages :
(1) Consistent process plans
(2) New components can be planned
easily.
(3) Automation is easy because it
gives a detailed control information.
 Disadvantages :
(1) Complex and very difficult to
develop
 Software's used : CMPP, EXCAP
XPLAN