Grinding path planning for the cutting teeth of helical broaching tool

Despite helical broaching being an excellent method for internal helical ring gear manufacturing with regard to its machining efficiency and precision, the manufacture of this special helical broaching tool is a severe challenge because of its complex geometric structure like dual-spiral and step-feed pattern of cutting teeth as well as the tiny offset of its cutting edges, particularly considering the expensive tool cost and long manufacturing period. Aiming at finding an efficient and reliable machining method for this type of helical broaching tool, this paper developed a complete set of machining routes and corresponding paths to grind its cutting teeth. Through detailed investigation, the geometric structure of the helical broaching tool, the tooth index model, and two kinds of tooth coordinate calculating methods were proposed. The rough cutting section is suggested to be machined in four stages, while the length-varying reciprocating path and the single-tooth grinding path patterns are presented. Then, a special step-feed structure-driven grinding path pattern and three stages are developed to perform the manufacture of the finishing cutting section. Finally, the progressively truthful machined entities validate that the developed machining routes and three path patterns are practicable for helical broaching tool manufacturing and that they are effective in enhancing the machining efficiency and quality. In addition, the concise operations prove the friendly programmability of the grinding paths.