What is process planning .Difficulties in traditional process planning,CAPP Model,Types of CAPP ,1.Retrieval type CAPP (variant) systems. 2.Generative CAPP systems. 3.Hybrid CAPP systems. Process planning system , Machinability data systems , Benefits of CAPP

1. Computer – Aided process
planning (CAPP)

3. What is process planning
1. Process planning is concerned with determining
the sequence of individual manufacturing
operations needed to produce a given part or
product.
2. The resulting operation sequence is documented
on a form referred to as route sheet.
3. The route sheet is a listing of the production
operations and associated machine tools for a
work part or assembly.

4. Difficulties in traditional process planning
1. There are variations in the level of details found in route
sheet among different companies and industries.
2. In one extreme case , process planning is accomplished
by releasing the part print to production shop with the
instructions (make to drawing)
3. Most firm provide a more detailed list of steps
describing each operation and identifying each
work centre.
4. Traditionally the task for manufacturing engineers
in an firm to write these process planning for new
part designs to be produced by the shop.
5. Process planning procedure is highly dependent
on the experience and judgement of the planner.
6. Manufacturing engineer responsibility to determine
an optimal routing for each new part design

5. CAPP Model

6. Computer-Aided process planning (CAPP)
1. In the view of the problems encountered with
process planning , attempts have been made to
capture the logic , judgements and experience
required for this important function and to
incorporate them into computer programs.
2. The program automatically generates the
manufacturing operation sequence.
3. CAPP reducing the routine clerical work of
manufacturing engineers.
4. The following alternative approaches to CAPP
have been developed:
1.Retrieval type CAPP (variant) systems.
2.Generative CAPP systems.
3.Hybrid CAPP systems.

7. 1.Retrieval type CAPP (variant) systems.
Thevariantprocess planning approach canbe
realized as a four stepprocess
1. Definition of codingscheme
2. Grouping parts into part families (Group
Technology)
3. Development of astandard processplan
4. Retrieval and modification of standard process
plan

8. 1.Retrieval Type CAPP (variant) systems
1. In this approach the parts produced in the plant are grouped into
part families and distinguished according to their manufacturing
characteristics.
2. For each part families, a std process plan is established.
3. The std process plan is stored in computer files and then retrieved
for new work parts, which belongs to that part family.
4. The CAPP program then searches the part family matrix file to
determine if a match exists
5. If the file contains an identical code number , the std machine
rooting and the operation sequence are Retrieval from the
computer file for display for user
6. The std process plan is examine and edited the part design and
prepare part document in proper form.
7. If an exact match cannot found the between the code numbers in the
computer file and the code number for new part, the user search the
machine root file and the operation sequence file for similar part that
can used to develop the plan for the new part.

10. 2.Generative process planning
1. It is the system which creates plan by means of decision logic,
formulas, geometry based data and other logical
procedures.
2. In this method process plans are prepared without the
assistance of human and predefined plans
3. The computer would employed a set of algorithms to
progress through the various technical and logical
decisions towards the finial plan for mfging
4. After retrieving this information, the system can generate the
required processes and process sequences for the work part.
5. A pure generative system can produce a complete process plan
from GT codes with part classification and design data,

12. Two major components of
generative
Geometry description and coding component:
• This defines all geometric features for process related surfaces
together with feature dimensions, locations, tolerances and the
surface finish desired on the features.
• The level of detail is much greater in a generative system than a
variant system.
Process knowledge database & decision making logic:
• The knowledge will be in the form of decision logic.
• It is required to match the part geometry requirement with
manufacturing capability using decision logic and data.
• It includes selection of processes, mfg. equipment's, work
holding devices, jigs & fixtures, inspection instruments, etc.

13. Geometric definition
From CAD
Part interrogation
Feature extraction
Feature recognition
Selection of
process
Selection of
M/C tool
Operations and
Timecalculations
Interferencesystem
M/C specification
& capability
Knowledge
Acquisition
Knowledge
Base
Final
Process
Plan
Diagram of Generative process Plan

14. 3.Hybrid CAPP System

15. Process planning system

16. Machinability data systems
The machinability data systems are based
on two types
1. Mathematical modeling based on the
empirically derived equations that fit a
range of experimential data.
1. Database systems that enable
machinability data occurred from a large
database

17. 1. Mathematical modeling represents machinability
variables in terms of machining parameters.
In general a machinability parameters variable y (metal
removal rate , tool wear rate , part surface finish) can
be expressed as: y=f(x1,x2,x3,x4) where x1,x2,x3,x4
are metal cutting parameters.
The most important mathematical model for the metal
cutting processes is taylor s tool life.
vtn =c
v is cutting speed
T is tool life in minutes
n is empirically derived tool life exponent
c is const of material

18. 2.Database systems

20. Benefits of CAPP
Productivity
Consistency
of plans
Accuracy
Of plans
Capacity
utilizatio
n
Ability to
Introduce
New
technology
Lead time of
Process plan
Routine clerical
work
Mfg. and
process
Planning
cost
Work in
progress
Skill requirement
Of planner
Increases Reduces

22. Computer- aided Manufacturing
Resource Planning

23. Introduction
1. In recent years,manufacturing has become
highly competitive world wide
2. It has become essential to control production
and inventory to the increased demand of
productivity.
3. The use of computers in manufacturing has
resulted in the development of Material
resource planning (MRP).
4. This concept has been extended to
manufacturing resource planning (MRP II),
Capacity resource planning (CRP) ,and
enterprise resource planning (ERP).

24. Material Resource Planning (MRP)
1. MRP is computational technique that converts
master schedule for end products into a detailed
schedule for the raw materials and components
used in the end products.
2. It is an inventory control system.
3. The basic MRP concepts are :
1.Independent and dependent demand.
2.Lumpy demands.
3.Manufacturing lead times.
4.Common use items.

25. 1.Independent and Dependent Demand
1. Independent demand is the demand for a
product , which is unrelated to the demand for
other items.
Example: End products and spare parts are
independent demand.
2.Depending demand is the demand for the
item, which is directly related to the demand for
other items
Example :Piston and cylinder of an automobile
engine are dependent demand.
MRP is a technique for determining the
quantities of dependent demand items.

26. Lumpy Demand
1. In a manufacturing system, when the demand
becames very large for a certain item, it is
referred to as lumpy demand.
2. MRP is an appropriate technique for
determining the inventory of lumpy demand items.

27. Manufacturing Lead times
1. Manufacturing lead time is the time required to
process the part through the sequence of
workstations specified on the route sheet.
2. It includes both productive and non - productive
times.
3. In MRP , lead time is used to determine the
stating dates for assembling final products and
sub - assemblies , for manfacturing component
part and for ordering raw materials.

28. Common Use items
1. In a manufacturing environment , certain
components become common items for the
assembling of several final products and sub
-assemblies.
Example:the same type of steel rod stock
may be used to produce different types of
screws.
2. MRP collects these common items required
for different products for ordering the raw
materials and manufacturing the components.

29. Inputs to MRP:
● MRP converts the master
production schedule into the
detailed schedule for raw materials
and components
● The inputs to MRP are:
1.The master production schedule
and service parts.
2.The bill - of - materials file.
3.The inventory record file.

31. 1.Master production Schedule
● The master production schedule is a list of:
1.Types of end products manufactured.
2.Number of each product produced
3.The time when the products would be ready
for shipment.

33. 2.Bill-of-materials file:
It consists of list of component parts and
sub-assemblies that make up the end point.
3 .Inventor Record File :
1.Computerised inventory system is used to
maintain the inventory record file.
2.A definition of the lead time for the raw
materials,components and assemblies must be
established in the inventory record file.
3.The inventory record file is maintained by
inputting the inventory transactions to the file.

34. MRP output Records
The MRP program generates the following outputs:

35. Manufacturing Resource Planning (MRP II)
1. This is an information system used to plan and
control inventories and capacities in manufacturing
companies.
2. MRP II coordinates the sales , purchasing ,
manufacturing, finance and engineering functions.
The various modules of MRP II are follows:
1.Manufacturing Applications
2.Engineering applications.
3.Financial Applications.
4.Marketing applications.

37. Capacity Requirements Planning (CRP)
● CRP is a technique for determining the
personnel and equipment capacities that are
required to meet the production objectives
specified in the master production schedule
and material requirement.

38. The inputs to the CRP are:
1.planned orders and released orders from the MRP
system
2.loading information from the centre status file.
3.Routing information from the shop routing file.
4.Changes (alternative routings , Capacity of new
equipments ,etc )
The released and planned orders from the MRP
system are converted into standard hours of
loading by the CRP system
The major outputs of CRP are:
1.load reports
2.Verification of planned orders for MRP system.

39. Enterprise Resource Planning (ERP)
● The activity of ERP is the creation of an
integrated data model , covering employees,
customers,suppliers,etc

40. ● The implementation of ERP systems includes
the following stages: