仪器制造技术-光整加工 - 2.ppt

三块平板对研 超精加工 20Hz，不能说是超声加工 Superfinishing of a Cylindrical Part Schematic illustration of the superfinishing process for a cylindrical part: (a) cylindrical microhoning; (b) centerless microhoning. 特点 运动： 1；磨头轴向进给运动2；磨条高速往复振动3。这三种运动使磨粒在工件表面形成的轨迹是正弦曲线。 超精加工大致可分为四个阶段： ????强力切削阶段 油石磨粒细，压力小，工件与磨条之间的油膜易形成，单位面积上的压力大，故切削作用强烈。 ????正常切削阶段 当少数凸峰磨平后，接触面积上的压力降低，切削磨条自锐性作用减弱，进入正常切削阶段。 ????微弱切削阶段 随着切削面积的增大，单位面积上的压力更低，切削作用微弱，且细小的切屑形成氧化物而嵌入油石空隙中，使油石产生光滑表面，具有摩擦抛光作用而降低工件表面的粗糙度。 ????自动停止阶段 工件磨平，单位面积上压力极低，工件与磨条之间又形成了油膜，切削作用自动停止。 ???? 超精加工的特点 ????① 超精加工磨粒运动轨迹复杂，能由切削过程过渡到抛光过程，表面粗糙度Ra值达0.01-0.04 μ m。 ????② 超精加工磨条的粒度极细，只能切削工件凸峰，所以加工余量很小，一般为0.005-0.00025mm。 ????③ 磨条高速往复振动，磨条的微刃两面切削，磨屑易于清除。不会在工件表面形成划痕。 ????④ 切削速度低，磨条压力小，工件表面不易发热，不会烧伤表面，也不易使工件表面变形。 ????⑤ 超精加工的表面耐磨性好。 胡批：和磨削比，没有热效应，没有应力产生，效率非常高，精度和磨削接近。 Honing Tool Schematic illustration of a honing tool to improve the surface finish of bored or ground holes. Honing In honing, a simultaneous rotating and reciprocating motion between an abrasive stone and the workpiece causes the removal of a small amount of material.? The resulting workpiece surface is one of high precision and uniform finish. 珩磨机 抛光与研磨的区别 Polishing Polishing is used to remove scratches and burrs and to smooth rough surfaces by means of abrasive grains attached to a polishing wheel rotating at high speed ( around of 7500 ft/min). The wheels are made of canvas帆布, leathers, felt羊毛毡, and even paper, thus the wheels are somewhat flexible. Magnetic Fluid Polishing 机械化学抛光 为了超越普通拋光加工精度极限並改善加工效率，在拋光加工中引入化学作用 在加工液中加入特殊的液性物质，或利用粉末粒子和加工物间的固相反应 In polishing with a chemical reaction, the greater the chemical action, the higher the processing efficiency and the thinner the damaged layer, but the lower the precision of the polished surface. Efforts are therefore made to obtain good precision by restraining chemical action to a certain degree. In lapping, the efficiency increase almost in proportion to the size of the abrasive, but the relation is not so noticeable in polishi