Transient Phenomenon of Chip Generations and movements in hobbing

本研究旨在借由观察滚齿过程中的暂态现象，以厘清滚齿磨损、滚齿表面粗糙度与切屑产生之间的机制。进行了滚切试验和模拟试验，测量了切屑的飞行轨迹，观察了切削刃与切屑的分离情况。总结了他们的主要成果。(1)切削刀具与导热系数不同的被切削材料的组合，可以改变卷曲等切屑的形状。根据切屑形状的不同，将切屑的飞行轨迹大致分为三类。(2)新切屑与附着切屑之间的干涉在一个旋转之前因切屑的形状而异。退火Cr-Mo钢（JIS SCM 415）的切屑容易发生干涉。(3)针对平面式飞刀上铣时，使用金属陶瓷刀具而不是硬质合金刀具时切屑飞离工件的问题，建立了滚齿仿真模型，模拟了单飞刀滚齿的切削条件， ...更多信息 相同滚刀齿和滚齿机。给出了模拟试验中飞刀切削瞬态现象的结果。(4)在刀具前刀面有涂层的情况下，切屑不能附着在前刀面上，导致飞屑。(5)在高速钢刀具前刀面无涂层、干切削的情况下，刀具在旋转一周之前，以切屑附着在前刀面上的状态切入工件，新生成的切屑将附着在前刀面上的旧切屑挤出飞出。(6)当切屑由上、侧刃同时产生时，切屑在刃角处受到强烈的干涉，并随着形状的改变而流出。(7)切屑的流动方向由切削刃的切断点改变。在斜齿轮滚切加工中，由于切屑点在一侧切削刃的根部，切屑在前刀面上侧向附着的情况时有发生。这种现象被认为是附着在齿面上的侧向切屑脱落，导致齿面质量下降。少

This research aims at clarification of mechanisms between hob wear, surface roughness of hobbed tooth and chip generation by observation of transient phenomenon in hobbing. Hobbing and simulation tests, measurement of chip's flight course and observation of separation between cutting edge and chip are performed. Their main results are summarized.(1) The shape of chip such as curl is changed by the combination of cutting tools and work materials having different heat conductivity. Three types of chip's flight courses are divided roughly owing to shapes of chips.(2) The interference between new chip and attached chip before one revolution is differed by shapes of chips. The interference of chips of annealed Cr-Mo steel (JIS SCM415) occurs easily.(3) Chips fly away from work-piece by using cermet tools rather than cemented carbide tools in the case of up milling with plane type flytool.Hobbing simulation is built up, that simulates cutting condition of hobbing by using single flytool with … More identical hob tooth and hobbing machine. The result of transient phenomenon of flytool cutting in simulation tests is shown.(4) The chip doesn't attach on the rake face of flytool, resulting in flying away in the case of coated rake face.(5) In the case of none coated rake face of high speed steel flytool and dry cutting, the flytool cuts in work-piece as attached on the rake face with the chip before one revolution, and then the old attached chip is pushed out by new produced chip and flies away.(6) The chip is interfered strongly at the comer of cutting edge when it is produced by both of the top cutting edge and side one at the same time, and flow out as changing the shape.(7) The flow direction of chip changes by the cut off point of the cutting edge. In helical gear hobbing, the cases that the chips attach sideways on the rake face are observed many times as the cut off point is at the root of one side cutting edge. This phenomenon is considered that the attached sideways chip is tom off on the tooth surface, resulting in degradation of surface quality. Less