Experimental studies on helical milling process to improve hole quality for the Superalloy (MSRR7197)

Conventional drilling is widely adopted to manufacture holes in difficult-to-cut materials such as superalloys. However, as a newer hole processing technology, helical milling possesses several advantages including low cutting forces, reduced tool wear, and improved hole quality. In this study, different hole-making processes like conventional drilling and helical milling were conducted on the superalloy (MSRR7197). Combining the deformation mechanism of the hole wall material, the influence of both hole-making processes on the processing quality of the MSRR7197 were investigated. The experimental results demonstrate that the axial force for the helical milling is about 1/10 of that for the drilling. Compared with drilling, the flank wear, rake wear, and wear of tool tip for the helical milling are smaller. The hole wall quality such as surface morphology and roughness of helical milling is better than that of the drilling. Last but not least, the helical milling can get a higher machining accuracy such as circularity and aperture. Hence, helical milling remains the favorable and alternative to conventional drilling.