Proposal of Low-Radial and High-Axial Immersion Machining of Hard Materials with Highly-Varied-Helix End Mill

—Experimental Verification of Proposed Method and Its Comprehension by Regenerative-effect Cancelation Diagram—

Abstract

Grinding has widely been applied to the peripheral finishing of hard materials like hardened steel, since the milling process often causes the regenerative/mode-coupling chatter vibrations due to high specific cutting force and low stiffness of slender end mills. A new machining method is proposed in which high-efficiency peripheral finishing of hard materials is realized with highly-varied-helix end mills at low-radial immersion. Large axial depth of cut (high surface generation rate) can be attained by the proposed method, because the mode-coupling chatter is avoided by setting the radial immersion to be small and the regenerative chatter is suppressed by using the highly-varied-helix end mills. This paper presents experimental verification of the proposed machining method and comprehensive explanation of its stability increase by utilizing “regenerative-effect cancelation diagram” proposed in this study.