Software Based Machining Adaptive Control and Its Effect Evaluation for Milling Operation

摘要

The needs for high-speed machine tool systems are dramatically increasing in automobile and aerospace industries. However, high speed machining poses some new problems such as rapid spindle failure, unacceptable parts due to chatter, and cutter breakage resulted from a sudden load change or an excessive load in the high speed if the cutter, cutting conditions and fixtures are not selected carefully. The objective of this research is to develop a software-based adaptive control system to keep a constant cutting load during the cutting process through adjusting the feedrate. By doing so, it is expected that a stable machining process can be attained with a maximum or designed material removal rate, and furthermore the breakage frequency of cutting tools can be reduced. To realize this concept, a simulation system for the calculation of material removal rate (MRR) was first developed. Then, the calculated MRR is compared to the predesigned value that is decided by the machine tool's capability. According to the comparison results, the feedrate is optimized and output for the control of the feed drive system of the machine tool. In this paper, the proposed system and its implementation is presented. Experiments for cutting a connection rod mold were conducted to verify the effectiveness of this system in the aspects of avoiding tool breakage and improving the tool wear and machining efficiency.