我厂加工汽车直拉杆螺纹的M3.9×1.5丝锥,经常在切削锥部的螺纹上粘结切屑瘤,使工件和丝锥大批报废,造成损失每年达35000元。分析粘结切屑瘤的主要原因,当攻丝到位后,返转回程的瞬间,丝锥的每一切削刃需要切掉原来的切屑根,此时的前角γ′=90°-β(后角),成了很大的负前角,切削很不利,由于摩擦和工件材料与刀具材料分子的亲合作用,至使在切削锥部后面的齿纹上,逐渐粘上切屑瘤。增至一定程度后,开 I plant the car straight rod thread M3.9 × 1.5 tap, often in the cutting cone thread adhesion to the chip tumor, a large number of scrapped parts and taps, resulting in loss of up to 35,000 yuan each year. Analysis of the main reasons for the adhesion of the chip tumor, when the tapping in place, the return of the moment back, each cutting edge of the tap need to cut off the original chip root, the front angle γ ’= 90 ° -β ), A very large negative rake angle, cutting very unfavorable due to the friction and the workpiece material and the affinity of the cutter material molecules, so that in the cutting cone on the back of the tooth pattern, and gradually stick to the chip tumor. Increase to a certain extent, open