Step-by-Step Machining of Cylindrical Worms with a Preset Axial Profile

Abstract

In practice, worm surfaces are most often shaped as cone-derivative helical surfaces. Much less often, due to engineering difficulties, torus-derivative or other helical surfaces are used. Whereas, worms are most commonly machined with rotary tools by the hobbing method, whereby the tool action surface and the machined surface (being mutually enveloping) contact with each other over the entire profile height. In the case of the step-by-step method, the tool is a small-diameter finger mill, whose action surface is coupled with the surface being machined, thus it is an universal tool. As a result, it is possible to shape a helical surface with a preset arbitrary axial profile using the same tool. The machining is carried out in many passes on a CNC machine tool. The paper discusses the determination of the parameters of tool setting in the worm axial plane for the programming of a CNC machine tool.