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1、第九章Lapping研磨Lappingisafinishingoperationusedonflatandcylindricalsurfaces.Thelap,showninFig.9.1a,isusuallymadeofcastiron,copper,leather,orcloth.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。Theabrasiveparticlesareembeddedinthelap,ortheymaybecarriedthroughslurry.Dependingonthehardnessoftheworkpi
2、ece,lappingpressuresrangefrom7kPato140kPa(1to20psi).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。Lappinghastwomainfunctions.Firstly,itproducesasuperiorsurfacefinishwithallmachiningmarksbeingremovedfromthesurface.Secondly,itisusedasamethodofobtainingveryclosefitsbetweenmatingpartss
3、uchaspistonsandcylinders.
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过盈配合的方法。Thelappedworkpiecesurfacemaylooksmoothbutitisactuallyfilledwithmicroscopicpeaks,valleys,scratchesandpits.Fewsurfacesareperfectlyflat.Lappingminimizesthesurfaceirregularities,therebyincreasingtheavailablec
4、ontactarea.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。ThedrawinginFig.9.1ashowstwosurfaces.Theupperoneishowasurfacemightlookbeforelappingandtheloweroneafterlapping.Lappingremovesthemicroscopicmountaintopsandproducesrelativelyflatplateaus.Entiremicroscopicmountainranges
5、mayneedtobegrounddowninordertoincreasetheavailablecontactarea.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。ProductionlappingonflatorcylindricalpiecesisdoneonmachinessuchasthoseshowninFig.9.1band9.1c.Lappingisalsodoneoncurvedsurfaces,suchassphericalobjects
6、andlenses,usingspeciallyshapedlaps.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Polishingisaprocessthatproducesasmooth,lustroussurfacefinish.Twobasicmechanismsareinvolvedinthepolishingprocess:(a)fine-scaleabrasiveremoval,and(b)softeningandsmearingofsurfacelaye
7、rsbyfrictionalheatingduringpolishing.抛光是生成平滑、有光泽表面光洁度的工艺。抛光工艺涉及两种基本机理：(a)精细等级磨粒去除，和(b)在抛光中通过摩擦生热软化并抹光表面层。ElectropolishingElectropolishingisanelectrochemicalprocesssimilarto,butthereverseof,electroplating.Theelectropolishingprocess
