In any manufacturing setting, producing a machined part is a complicated, multi-step process. It requires coordination between an engineer and a machinist to ensure all goals are met. A machinist creates a part based generally on personal experience and intuition, and while they know that this will result in the finished product, it is not guaranteed that the process plan chosen is the quickest or least expensive way to make the part. In the past year, we have been developing an automated tool that analyzes a solid model to determine its best process plan. The tool is essentially comprised of a reasoning engine that determines what processes are valid for particular sections of the part, and an evaluation engine that estimates the time and cost of the candidate processes.
This paper presents the implemented evaluation engine, which assigns individual values of time and cost to machine operations. The evaluation starts with an automated tool selection strategy. The engineering model is able to determine the machining time of the tool(s) chosen. The method presented here takes a unique approach to machining time estimation that balances the trade-off between accuracy and computational time. Preliminary results suggest that the method is able to achieve accuracy near that of commercial CAM packages, with a much lower computational expense. The evaluation model takes into account non-productive manufacturing times (e.g. fixturing, inspection), and translates these to related costs. The method will be presented and discussed in this paper along with some preliminary results.