An integrated computer simulation system to evaluate surface integrity in end milling.

摘要

A computer based process simulating system for end milling is developed to evaluate cutting force, stability, tool wear, surface generation, and surface integrity of a product during design and process planning phase. This overall simulation is an integration of PC-based modules to evaluate dynamic stability (chatter), tool wear, cutting forces, surface generation, and maximizing production rate for end milling. The cutting force, surface generation and tool wear modules were developed by some modifications to the models reported in the literature. Also, a finite element model was developed to calculate instantaneous residual stress distributions in the milled surface.; The modules provide information of cutting forces, surface profiles, and roughness, cutting conditions for stable milling without chatter, and estimation of tool wear such as flank wear and crater wear which are generated during the end milling operation. The developed system is designed in a modular fashion, so that changes in process models can be easily incorporated. Limited experiments were performed to validate the predictions of the modules.; The following conclusions were obtained from the research: (1) The developed cutting force module can predict important information of cutting force signals such as shape and approximate magnitude. (2) The critical chip thickness to provide stable end milling operation without chatter can be calculated. (3) Tool wear module can provide qualitative and quantitative progress of tool wear in end milling. (4) Surface generation module can provide roughness of milled surface within the range of maximum 33.5% and minimum 2.2% for the new tool. Although there were discrepancy between measured roughness and simulated one for the worn tool case, the simulation module can predict spatial frequency of roughness. (5) Production rate can be increased satisfying the given tool wear, roughness and cutting force under the stable end milling operation. (6) The FEM model can predict the instantaneous residual stress distribution with reasonable accuracy.