Using mixed-type reasoning in computer-aided process planning for feature interactions

This paper describes a process-planning model using mixed-type reasoning designed for processing prismatic parts on CNC machine tools in a batch manufacturing environment. This mixed-type reasoning handles feature interactions by combining forward chaining for feature sequencing and backward chaining for the construction of a process plan. In such a model, the human problem-solving strategies are decoupled from the tools for analysis and sorting algorithms. Two databases are used to contain the results from forward and backward chaining. The process-planning algorithm combines the processes of modeling the given information in four stages: (1) defining the important information for features and feature-related concerns; (2) interpreting and rearranging the given feature according to the given constraints and sorting guideline; (3) sequencing the features; (4) attaching the needed operations to the features in machine/process/feature/set-up/tool/time format.