CAPP
Computer-aided Process Planning CAPP
The major research efforts at the interface between CAD and CAM have been in the development of computer-aided process planning systems, which attempt to automate the communication process between product designers and manufacturing engineers.
Computer-aided process planning tool can be represented as having two separate functions, product/ process analysis and process planning proper
Data exchange between CAD and CAM
A two-stage process results, in which CAD data is examined for process/ product analysis of the parts, and design for manufacturing and design for assembly guidelines are applied to this design data and the results fed back to the designer, after which the redesign may occur. Process planning thereupon receives parts that have been “passed” by product/ process analysis and generates manufacturing instructions for their manufacture.
Group Technology
In group technology GT, components are grouped into families on the basis of similarity of such features as part shapes, part finishes, materials, tolerances and required manufacturing processes. Gallagher and Knight define group technology as “a technique for identifying and bringing together related or similar components in a production process in order to take advantage of their similarities by making use of, for example, the inherent economies of flow-production methods”.
GT helps to minimize unnecessary variety of components in manufacturing plant by making designers aware of existing similar components.
The use of GT codes to retrieve data is also useful when it comes to process planning.
GT forms component families on the basis of the design or manufacturing attributes -sometimes both- of the components in question.
A large number of commercially available computer-based systems have been developed to support the creation of GT codes, and indeed the retrieval of part information, part drawings, design information and even process planning information. The techniques of artificial intelligence have been applied to this area.
Parts classification and coding is concerned with identifying the similarities among parts and relating these similarities to a coding system. Part similarities are of two types: design attributes (such as geometric shape and size), and manufacturing attributes (the sequence of processing steps required to make the part). Accordingly, classification and coding systems are often devised to allow for differences between a part’s design and its manufacture.
