Abstract
BTA deep hole drilling is used for producing holes of high aspect ratio. In this process, a chatter vibration sometimes occurs and a rifling mark is formed on the surface of the hole. The generating mechanism of the rifling mark in BTA deep hole drilling process has been studied as a self-excited vibration caused by time delay. As a countermeasure, the authors analyzed the effect of the BTA machining head which has three guide pads theoretically, and suggested the optimum angle to prevent the pattern formation. However, the experimental approaches for the pattern formation phenomena in BTA deep hole drilling and its countermeasure have not been established yet. In this paper, the pattern formation phenomena using the normal tool are examined and the preventing method by an additional guide pad is evaluated in the experiments.
