A seminar report on:Computer Aided Process

Planning Submitted by:

Abinash Jena

Birla Institute of Technology,Mesra

INTRODUCTION CAPP is the use of computer technology to aid in the

process planning of a part or product in manufacturing. CAPP is the link between CAD and CAM in that it provides

for the planning of the process to be used in producing a designed part.

Process planning is a production organization activity that transforms a product design into a set of instruction (sequence, machine tool setup etc.) to manufacture machined part economically and competitively.

CAPP is the method of automatically generating the sequence of manufacturing operations

Initial Form Final Form

CAPP is a direct connection between

design and manufacturing

Characteristics CAPP capable of understanding and analyzing

the part characteristics. It possess knowledge about machine tools, cutting

tools, etc.. It possess the capabilities of analyzing the

interdependencies between part, machining process, quality, cost.

It possess multiple calculating capabilities

Types of approaches:Variant process planningGenerative process planning

Variant process planning

The variant process planning approach can be realized as a four step process Definition of coding scheme Grouping parts into part families (Group

Technology) Development of a standard process plan Retrieval and modification of standard

process plan

Part coding &classification

Formation ofPart family

Preparation ofStandard plan

Part familysearch

Standard M/cRoute retrieval

StandardOperation retrieval

And editProcess plan

editor

Final process

plan

Operations sequence file

Part family matrix file

Machine routing file

Other applications file

Preparatory stage

Production stage

Diagram of Variant process plan:

Generative process planning:

It is the system which creates plan by means of decision logic, formulas, geometry based data and other logical procedures.

In this method process plans are prepared without the assistance of human and predefined plans

After retrieving this information, the system can generate the required processes and process sequences for the work part.

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. equipments, work

holding devices, jigs & fixtures, inspection instruments, etc.

Geometric definitionFrom CAD

Part interrogationFeature extractionFeature recognition

Selection ofprocess

Selection ofM/C tool

Operations andTime calculations

Inte

rfere

nce

syst

em

M/C specification& capability

KnowledgeAcquisition

KnowledgeBase

FinalProcess

Plan

Diagram of Generative process Plan:

Benefits of CAPP:

ProductivityConsistency of plansAccuracy of plans

Capacity utilization

Ability to Introduce New

technology

Increases

Lead time ofProcess plan

Routine clerical work

Mfg. and process Planning cost

Work in progress

Skill requirement Of planner

Reduces

Thank you