unit9研磨与抛光.ppt

Professional English 北华大学机械学院 王开宝 Unit 9 Lapping 研磨 Lapping is a finishing operation used on flat and cylindrical surfaces. The lap, shown in Fig.9.1a, is usually made of cast iron, copper, leather, or cloth. 研磨是一种用于平面和圆柱面的精加工作业。研具，如图9.1a所示，通常用铸铁、铜、皮革或布制成。 Laptop Desktop The abrasive particles are embedded in the lap, or they may be carried through slurry. Depending on the hardness of the workpiece, lapping pressures range from 7kPa to 140kPa (1 to 20 psi). 研磨微粒嵌入研具内，或者可以通过液体携带。根据工件硬度，研磨压力可在7kPa到140kPa(1到20psi)范围中取。 Lapping has two main functions. Firstly, it produces a superior surface finish with all machining marks being removed from the surface. Secondly, it is used as a method of obtaining very close fits between mating parts such as pistons and cylinders. 研磨有两个主要作用。首先，它通过去除所有机加工痕迹能产生较好的表面光洁度。其次，它能用作获得像活塞与气缸之类配件间紧密配合的方法。 The lapped workpiece surface may look smooth but it is actually filled with microscopic peaks, valleys, scratches and pits. Few surfaces are perfectly flat. Lapping minimizes the surface irregularities, thereby increasing the available contact area. 研磨后的工件表面可能看似平滑，其实布满着微观峰、谷、划痕和凹陷。几乎没有表面是完全平整的。研磨使表面不规则最小化，因而增加了有效接触面积。 The drawing in Fig.9.1a shows two surfaces. The upper one is how a surface might look before lapping and the lower one after lapping. Lapping removes the microscopic mountain tops and produces relatively flat plateaus. Entire microscopic mountain ranges may need to be ground down in order to increase the available contact area. 图9.1a上显示了两个表面。上面是研磨前表面可能的外观模样而下面则是研磨后的模样。研磨去除了微观峰顶从而产生相对平坦的平台。整个微观山脉范围都需要磨去以增加有效接触面积。 Production lapping on flat or cylindrical pieces is done on machines such as those shown in Fig.9.1b and 9.1c. Lapping is also done on curved surfaces, such as spherical objects and lenses, using specially shaped laps. 研磨平面或圆柱面工件的生产过程是在如图9.1b和9.1c那样的机器上完成的。研磨也可采用特殊成型研具在诸如球形物体和透镜之类的曲面上进行。 Polishing 抛光 Polishing is a process that produces a smooth, lustrous surface finish. Two basic mechanisms are involved in t