Carbon fiber-reinforced resin (CFRP) is a difficult-to-cut material and is prone to burrs and surface delamination. We propose inclined planetary machining as a high-quality drilling method for CFRP. Inclined planetary machining is a method of drilling holes by inclining the tool and using precession motion, which is effective in suppressing burrs and surface delamination. It has also been shown that the quality of machined holes can be improved by using a geometric radius end mill. Here, we applied a radius end mill to inclined planetary machining to conduct continuous hole machining experiments in CFRP, and discuss the progress of tool wear and the quality of the machined holes. In addition, the influence of inclined planetary machining conditions on the machined hole quality was determined by analysis of variance.

In this study, plane bending fatigue tests were conducted for shot peened vacuum carburized SCM420H steel sampled from the rolling direction (RD) and transverse direction (TD). The results showed that the fatigue limit of the carburized steel without shot peening was approximately 32% higher in the RD direction than the TD direction. Most fractures in TD samples were generated from elongated inclusions. On the other hand, fractures in RD samples were generated from outside of nonmetallic inclusions. The low fatigue limit of TD samples was due to the presence of rolling-induced elongated inclusions along the direction of maximum principal stress.