Variant Process Planning

The variant approach to process planning is the first attempt to computerise the process planning technique. It is comparable to the traditional manual approach where, process plan for a new part is created by recalling, identifying and retrieving a present plan for a similar part (sometimes called as the master part) and making necessary modification to suit the new part. In variant systems, parts are grouped into a number of part families, characterised by similarities in manufacturing methods. This technique is based on the use of Group Technology (GT). In this case individual parts are coded based on a number of part characteristics and attributes. Part family comprises of parts having sufficient number of common attributes so that they can be grouped into a single family. A standard plan consists of a process plan, capable of being utilised for the entire part family. The standard plan is retrieved and edited to suit the new part.

A variant PP system is implemented in two stages:

• The preparatory stage, and
• The production stage.