CAPP

INTRODUCTION

Process planning translates design information into the process steps and instructions to efficiently and effectively manufacture products. As the design process is supported by many computer-aided tools, computer-aided process planning (CAPP) has evolved to simplify and improve process planning and achieve more effective use of manufacturing resources.

PROCESS PLANNING

Process planning encompasses the activities and functions to prepare a detailed set of plans and instructions to produce a part. The planning begins with engineering drawings, specifications, parts or material lists and a forecast of demand. The results of the planning are:

• Routings which specify operations, operation sequences, work centers, standards, tooling and fixtures.This routing becomes a major input to the manufacturing resource planning system to define operations for production activity control purposes and define required resources for capacity requirements planning purposes.
• Process plans which typically provide more detailed,step-by-step work instructions including dimensions related to individual operations, machining parameters, set-up instructions, and quality assurance checkpoints.
• Fabrication and assembly drawings to support manufacture (as opposed to engineering drawings to define the part).

Manual process planning is based on a manufacturing engineer's experience and knowledge of production facilities,equipment, their capabilities, processes, and tooling. Process planning is very time-consuming and the results vary based on the person doing the planning.

COMPUTER-AIDED PROCESS PLANNING

Manufacturers have been pursuing an evolutionary path to improve and computerize process planning in the following five stages:

Stage I - Manual classification; standardized process plans Stage II - Computer maintained process plans Stage III - Variant CAPP Stage IV - Generative CAPP Stage V - Dynamic, generative CAPP

CAPP BENEFITS

Significant benefits can result from the implementation of CAPP. In a detailed survey of twenty-two large and small companies using generative-type CAPP systems, the following estimated cost savings were achieved:

• 58% reduction in process planning effort
• 10% saving in direct labor
• 4% saving in material
• 10% saving in scrap
• 12% saving in tooling
• 6% reduction in work-in-process

In addition, there are intangible benefits as follows:

• Reduced process planning and production leadtime; faster response to engineering changes
• Greater process plan consistency; access to up-to-date information in a central database
• Improved cost estimating procedures and fewer calculation errors
• More complete and detailed process plans
• Improved production scheduling and capacity utilization
• Improved ability to introduce new manufacturing technology and rapidly update process plans to utilize the improved technology

If you are interested in Manufacturing planning and control system, then check below linked ppt.

http://www.me.metu.edu.tr/courses/me445/Assets/lecture%20notes/ch8%20Manufacturing%20Planning%20and%20Control%20Systems.ppt.