機械精密加工是(shi)一種用加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)機械對(dui)工(gong)(gong)(gong)(gong)件的(de)(de)外形尺寸或性能進行改變的(de)(de)過程。按(an)被加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)的(de)(de)工(gong)(gong)(gong)(gong)件處于的(de)(de)溫(wen)度狀態﹐分為(wei)冷(leng)(leng)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)和(he)熱(re)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)。一般(ban)在常溫(wen)下加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong),并且不引起(qi)工(gong)(gong)(gong)(gong)件的(de)(de)化(hua)(hua)學或物相(xiang)變化(hua)(hua)﹐稱(cheng)冷(leng)(leng)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)。一般(ban)在高于或低(di)于常溫(wen)狀態的(de)(de)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)﹐會引起(qi)工(gong)(gong)(gong)(gong)件的(de)(de)化(hua)(hua)學或物相(xiang)變化(hua)(hua)﹐稱(cheng)熱(re)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)。冷(leng)(leng)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)按(an)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)方(fang)式的(de)(de)差(cha)別可分為(wei)切削加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)和(he)壓(ya)力加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)。熱(re)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)常見有熱(re)處理﹐鍛造(zao)﹐鑄造(zao)和(he)焊接。

機械精密加工廠常見的磨損類型主要包括跑合磨損、硬粒磨損、表面疲勞磨損、熱狀磨損、相變磨損和流體動力磨損這幾種。

跑合磨損是機械在正常載荷、速度及潤滑條件下出現的磨損，這種磨損一般發展較慢，短期內對加工質量影響不大。

硬粒磨損是由于零件本身掉落的磨粒或者由外界進入機床的硬粒，混入了加工區域，受到機械切削或研磨，引起零件的破壞，這對加工質量的影響是比較嚴重的。

機械精密加工廠表面疲勞磨損是機械在交變載荷的作用下，產生了微小裂紋或班點狀凹坑，從而造成零件的損壞。這類磨損通常與壓力大小、載荷特點、機件材料、尺寸等因素密切相關。

熱狀磨損是零件在摩擦過程中產生的熱量作用在零件上，使零件有回火軟化、灼化折皺等現象。這類磨損通常發生在高速和高壓的滑動摩擦中，磨損的破壞性比較大，并伴有事故磨損的性質。

腐蝕磨損是一種化學作用，即化學腐蝕造成磨損。當零件表面與酸、堿、鹽類液體或有害氣體接觸時，就會受到化學侵蝕，或零件表面與氧相結合生成易脫落的硬而脆的金屬氧化物而使零件磨損。

相變磨(mo)損是零件(jian)(jian)(jian)長期(qi)在高溫(wen)狀(zhuang)態下(xia)工作，零件(jian)(jian)(jian)表面金屬組織晶粒(li)受熱變大，晶界四周被(bei)氧化，產(chan)生了(le)細(xi)小的(de)間隙(xi)，使零件(jian)(jian)(jian)脆弱、耐磨(mo)性下(xia)降，從而(er)造(zao)成(cheng)的(de)零件(jian)(jian)(jian)磨(mo)損。