零件如图1所示,孔底面光洁度要求8。国外是用一种专用研磨橡胶棒来加工的。目前,我国还没有这种橡胶棒。我们采用钻头切削刃挤压的方法提高孔底的光洁度。钻头刃磨成图2的形状,顶角180°,修磨外缘处的前面以增加强度。用油石研磨钻头的两个切削刃;后角α=0°,有0.5～0.8毫米的过渡倒棱。用平底钻头把孔钻到接近孔深的下偏差,表面光洁度为6。然后换 Parts shown in Figure 1, the hole bottom surface finish requirements 8. Abroad is a special grinding rubber rod to process. At present, our country does not have such a rubber rod. We use the drill cutting edge extrusion method to improve the bottom of the hole finish. The sharpening of the drill into the shape of Figure 2, apex angle of 180 °, sharpens the front of the outer edge to increase strength. Grind the two cutting edges of the bit with whetstone; relief angle α = 0 °, with 0.5 to 0.8 mm over chamfer. Use a flat-bottomed drill to drill the hole to a near deviation of the hole depth with a surface finish of 6. Then change