| Computer
Aided Process Planning |
Introduction
Technological advances are reshaping the face of manufacturing, creating paperless
manufacturing environments in which computer automated process planning (CAPP)
will play a preeminent role. The two reasons for this effect are: Costs are declining,
which encourages partnerships between CAD and CAPP developers and access to manufacturing
data is becoming easier to accomplish in multivendor environments. This is primarily
due to increasing use of LANs; IGES and the like are facilitating transfer of
data from one point to another on the network; and relational databases (RDBs)
and associated structured query language (SQL) allow distributed data processing
and data access.
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With the introduction of computers in design and manufacturing,
the process planning part needed to be automated. The shop trained people who
were familiar with the details of machining and other processes were gradually
retiring and these people would be unavailable in the future to do process planning.
An alternative way of accomplishing this function was needed and Computer Aided
Process Planning (CAPP) was the alternative. Computer aided process planning was
usually considered to be a part of computer aided manufacturing. However computer
aided manufacturing was a stand alone system. Infact a synergy results when CAM
is combined with CAD to create a CAD/CAM. In such a system CAPP becomes the direct
connection between design and manufacturing.
Moreover, the reliable knowledge based computer-aided process planning application
MetCAPP software looks for the least costly plan capable of producing the design
and continuously generates and evaluates the plans until it is evident that non
of the remaining plans will be any better than the best one seen so far. The goal
is to find a useful reliable solution to a real manufacturing problem in a safer
environment. If alternate plans exist, rating including safer conditions is used
to select the best plans COMPUTER AIDED
DESIGN (CAD) A product must be defined
before it can be manufactured. Computer Aided Design involves any type of design
activity that makes use of the computer to develop, analyze or modify an engineering
design. There are a number of fundamental reasons for implementing a computer
aided design system.
a. Increase the productivity of the designer: This is
accomplished by helping the designer to visualize the product and its component
subassemblies and parts; and by reducing the time required in synthesizing, analyzing,
and documenting the design. This productivity improvement translates not only
into lower design cost but also into shorter project completion times.
b. To
improve the quality of the design: A CAD system permits a more thorough engineering
analysis and a larger number of design alternatives can be investigated. Design
errors are also reduced through the greater accuracy provided by the system. These
factors lead to a better design.
c. To improve communications: Use of a CAD
system provides better engineering drawings, more standardization in the drawings,
better documentation of the design, fewer drawing error, and greater legibility.
d.
To create a database for manufacturing: In the process of creating a the documentation
for the product design (geometries and dimensions of the product and its components,
material specification for components, bill of materials etc), much of the required
data base to manufacture the product is also created. Design
usually involves both creative and repetitive tasks. The repetitive tasks within
design are very appropriate for computerization.
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