Crack Propagation Analysis Of High Speed Dry Cutting Gear Hob Based On Extended Finite Element Method

High speed dry gear hobbing is one of the key technologies in high-speed dry hobbing. Its structure is complex and the manufacture is expensive. High-speed dry cutting hobbing is a complex multi-blade intermittent cutting process, gear hob is receiving high impact and complex loads. At the same time, due to the lack of cutting cooling and lubrication, the friction between cutter and workpiece is severe and the temperature of cutting zone is very high. Under the combined effect of the complex alternating mechanical load and thermal load, the tool may fail to produce chipping phenomenon.Chipping failure is one of the main failure modes in high-speed dry cutting hob. The main reason for chipping failure is the crack initiation and propagation in hob tooth and the chipping failure directly reduced the life of high speed dry cutting gear hob and it’s also seriously affects the quality and economic of gear hobbing processing. At present, carrying out research in this area is necessary, for the studies on high-speed dry cutting hob crack propagation are not sufficient.The paper is obtained by the support of 863 projects(2012AA040107). The high-speed dry cutting hob chipping is using by Extended Finite Element Method, the main contents are showed as follows:Firstly, the basic theory of fracture mechanics and XFEM are introduced for initial crack problem of high-speed dry hobbing. The crack tip stress field, displacement field, the stress intensity factor and fracture criterion are summarized, and its related equation is also derived.Secondly, the manufacturing process of high-speed dry cutting hob is analyzed and the characteristics of the traditional tool failures are summarized. At the same time, the failure characteristics of high-speed dry cutting hob are analyzed combined with the high-speed dry cutting hob process.Thirdly, the hob cutter geometry model is set up. High-speed dry hobbing movement is also determined. The high-speed dry hobbing simulation is implementing through the ABAQUS platform. The results showed that: the stress of side edge and the top edge are higher than the other place and it’s easy to initiation crack.Finally, the side edge and the top edge of initial crack model are set up by referring to the hob cutting stress cloud and the initial crack parameters. The crack propagation simulation analysis of high-speed dry hob is completed through the ABAQUS platform by using XFEM method. The results showed that: the crack growth track and regulation of high-speed dry hob are closely related to the location and parameters of cracks.