Study on Machining Accuracy Simulation of Deep Die Mold Cutting

—Enlargement of Contact Area in Steep Wall Machining and Simultaneous Analysis of Profile Error and Chatter—

Abstract

In aim to shorten lead-time of die fabrication, electrical discharge machining is being replaced with cutting. However, when cutting with tools of long extrusion length, achieving necessary accuracy becomes difficult due to chatter and machining remains. Therefore, cutting and measurement are repeated until satisfactory cutting conditions are achieved. Concerning this problem, we have developed a technique that analyzes profile error and surface roughness before machining, by simulating dynamic vibration of the tool. In the simulation, cutting force is calculated through integration of cutting force and edge force. It has been confirmed that taking in account the area where ploughing takes place due to the tool shape, takes a large role especially in deep die mold cutting. Also through the developed time domain simulation, the normal chatter free cutting conditions at around 0 degrees phase shift between the cut, was found to have large profile error. On the other hand, it has been found that at around 180 degrees phase shift, there is a condition where both chatter and profile error are suppressed, enabling high speed machining of deep die mold, without the need to repeat the same process in production, to satisfy the necessary accuracy.