We have already seen that many of the manufacturability evaluation systems use manufacturing plans for evaluating manufacturability. For this reason we include here a brief review of some representative systems of automated process planning.
Automated process planning is a key element in integrating design and manufacturing [151]. Many attempts have been made to automate process planning of machined parts [63,151,152,153,154,155,156]. The two traditional types of approach to computer-aided process planning are the variant approach and generative approach. The variant approach involves retrieving an existing plan for a similar part and making the necessary modifications to the plan for the new part. The generative approach involves generation of new process plans by means of decision logics and process knowledge. We are discussing only the generative approach of process planning as only in this approach one can develop a process plan at the early design stage where manufacturability evaluation is most effective. Also it does not keep the designer tied to earlier process plans and allows to develop alternative process plans for the same design. Usually, the task of process planning involves a number of inter-dependent activities. Most of these activities cannot be performed independently. Generation of the optimal process plan usually requires several iterations and even after significant progress although progress at present there are no automated process planning systems capable of automatically performing the complete task.
The generation of complete process plans is a complex task and requires many steps. This section only deals with those steps that are relevant to manufacturability analysis. For details and literature survey on the complete plan generation steps, readers are referred to [151,153,156].