computer aided process planning, approaches to capp, variant and generaive type

computer aided process planning, approaches to capp, variant and generaive type

1. Process Planning
•Link between product design and
Manufacturing
•Design output: Sketch
•Production dept output: Physical Product
•Process planning designs the bridge to convert
sketch in to physical product

2. Process Planning
•Determining the sequence of processing and
assembly steps to make the product
•Decides what types of equipment and tooling
are required to fabricate the parts and
assemble the product.
•Concerned with logistics issues of making
product
•Deals with ordering the materials and
obtaining the resource

3. Process Planner
•One who performs the planning task
•He should possess knowledge of:
–Interpretation of design drawing: dimension tolerances
and geometry related parameters
–Processes and sequence: Minimum shifts and changeovers
–Equipment selection:
–Tools , dies, molds, …
–Material handling methods: Hoist, crane, Fork lift,
automated….
–Standard parts
–Cutting conditions and time standards

4. Route sheet
•Output of process planning
•Includes..
–Material
–Size
–Operation description
–Dept
–Machine
–Tooling
–Setup and Cutting time

5. Part
No
Part Name PlannerChecked
By
Date Page
1 Plate -- -- -- --
Material size
No.Operation DescriptionDept MachineToolingSet upStd.
10 making faces right
angle byfiling
Fitting Files 5 min1 hr
20 Locating centers
30 Drilling through holes
dia8
Drill D10 Drill
J999
10
min
15 min
40 Tapping of dia8 Fitting- Tape and
tape
wrench
1 0
min
35 min
50 Locating buttons
60 Drilling Lathe
70 Boring Operation

6. •Process planning for machining
•Process planning for assembly

7. Sequence of processes required in part
fabrication
Secondary
Processes
Basic
Process
Property
Enhancing
Processes
Finishing
Process
Raw
Mat

8. Example
Basic ProcessStarting MatSecondaryProEnhan. ProcFinishing Proc
Sand CastingSand castingMachining - Painting
Rolling Sheet MetalPunching
Bending
Forming
- Plating
Painting
Rolling and Bar
drawing
Bar Stock Machining
Grinding
Heat Treatment‘’
Forging

9. Make or Buy decision
•Factors to consider:
–Cost
–Availability of in-house process
–Total production quantity
–Anticipated product life
–Standard
–Current capacity of plant
–Alternative supply need

10. Ex.
•Buy: 20/unit for 100 unit
•Make:
–Raw Mat. Cost = 8 / unit
–Direct labor cost= 6 / unit
–Overhead = 9 / unit
–Equipment fixed cost = 5 / unit
•What’s your choice?

11. CAPP
•Computer Aided process planning
•Benefits:
–Process standardization
–Increased productivity of process planner
–Reduced lead time
–Improved legibility
–Interfacing with other Cs i.e. CAM, CAD..

12. CAPP types
•Retrieval CAPP Systems
•Generative CAPP Systems

13. Retrieval CAPP Systems
•Based on the principles of GT
•Also called variant CAPP
•GT: Group Technology
–Concept of grouping parts together depending upon
their similarities in operation sequence or geometry
•Experts’ knowledge and standard process plans
as per GT are needed as data base
•Considerable work is required to collect and
organize copious data

14. New part design

15. Derive GT Code
number for part
New part design

16. Derive GT Code
number for part
Search part family file
for GT code number
Part Family file
New part design

17. Derive GT Code
number for part
Search part family file
for GT code number
Part Family file
Selecting coding
System and form part
families
Prepare standard
process plans for part
families
Preparatory
stage
New part design

18. Derive GT Code
number for part
Search part family file
for GT code number
Part Family file
Standard process
plan file
Selecting coding
System and form part
families
Prepare standard
process plans for part
families
Preparatory
stage
New part design

19. Derive GT Code
number for part
Search part family file
for GT code number
Retrieve standard
process plan
Part Family file
Standard process
plan file
Selecting coding
System and form part
families
Prepare standard
process plans for part
families
Preparatory
stage
New part design

20. Derive GT Code
number for part
Search part family file
for GT code number
Retrieve standard
process plan
Edit existing plan or
write new plan
Part Family file
Standard process
plan file
Selecting coding
System and form part
families
Prepare standard
process plans for part
families
Preparatory
strange
New part design

21. Derive GT Code
number for part
Search part family file
for GT code number
Retrieve standard
process plan
Edit existing plan or
write new plan
Process plan
formatter
Process plan
(Route Sheet)
Part Family file
Standard process
plan file
Selecting coding
System and form part
families
Prepare standard
process plans for part
families
Preparatory
strange
New part design

22. Derive GT Code
number for part
Search part family file
for GT code number
Retrieve standard
process plan
Edit existing plan or
write new plan
Process plan
formatter
Process plan
(Route Sheet)
Part Family file
Standard process
plan file
Selecting coding
System and form part
families
Prepare standard
process plans for part
families
Preparatory
stage
Other application
programs
New part design