精加工時主要零件加工的精度和表面質量

        CNC立式加工中心廠家談談在進行CNC零件加工中心時，根據(ju)零件的加(jia)工(gong)精度、剛度和(he)變形等元素來(lai)劃分工(gong)序時，應(ying)遵循粗、精加(jia)工(gong)分開(kai)則來(lai)劃分工(gong)序，即先粗加(jia)工(gong)全(quan)部(bu)完成之后再進行半(ban)精加(jia)工(gong)、精加(jia)工(gong)。對于某一加(jia)工(gong)表面(mian)，應(ying)按粗加(jia)工(gong)——半(ban)精加(jia)工(gong)——精加(jia)工(gong)順序完成。

        粗加(jia)(jia)工(gong)(gong)時(shi)(shi)應(ying)當(dang)在加(jia)(jia)工(gong)(gong)質(zhi)量(liang)(liang)、刀(dao)具(ju)耐用(yong)度(du)和機床——夾具(ju)——刀(dao)具(ju)——工(gong)(gong)件(jian)工(gong)(gong)藝系統的(de)剛性(xing)(xing)所(suo)允許的(de)條件(jian)下(xia)(xia)，充分發揮機床的(de)性(xing)(xing)能和刀(dao)具(ju)切削性(xing)(xing)能，盡(jin)量(liang)(liang)采用(yong)較大(da)的(de)切削次數(shu)得(de)到(dao)精(jing)加(jia)(jia)工(gong)(gong)前的(de)各部余(yu)量(liang)(liang)盡(jin)可能均勻的(de)加(jia)(jia)工(gong)(gong)狀況。精(jing)加(jia)(jia)工(gong)(gong)時(shi)(shi)主要零(ling)件(jian)加(jia)(jia)工(gong)(gong)的(de)精(jing)度(du)和表面(mian)質(zhi)量(liang)(liang)，故通常精(jing)加(jia)(jia)工(gong)(gong)時(shi)(shi)零(ling)件(jian)的(de)終輪(lun)廓(kuo)應(ying)由后一刀(dao)連續精(jing)加(jia)(jia)工(gong)(gong)而(er)成。為(wei)加(jia)(jia)工(gong)(gong)質(zhi)量(liang)(liang)，一般(ban)情況下(xia)(xia)，精(jing)加(jia)(jia)工(gong)(gong)余(yu)量(liang)(liang)以(yi)留0.2-0.6mm為(wei)宜，粗、精(jing)加(jia)(jia)工(gong)(gong)之間(jian)(jian)，好隔一段時(shi)(shi)間(jian)(jian)，以(yi)使粗加(jia)(jia)工(gong)(gong)后零(ling)件(jian)的(de)變形得(de)到(dao)充分恢復，再進行精(jing)加(jia)(jia)工(gong)(gong)，以(yi)提(ti)高零(ling)件(jian)的(de)加(jia)(jia)工(gong)(gong)精(jing)度(du)。

        一般在數控機床(chuang)上，特別是在(zai)(zai)加(jia)(jia)工(gong)中(zhong)(zhong)心上加(jia)(jia)工(gong)零件、工(gong)序可(ke)(ke)以(yi)大限度(du)集中(zhong)(zhong)，即(ji)零件在(zai)(zai)一(yi)次(ci)裝夾中(zhong)(zhong)應盡可(ke)(ke)能完成本臺數(shu)控機(ji)床(chuang)所能加(jia)(jia)工(gong)的(de)(de)大部分或全(quan)部工(gong)序、數(shu)控加(jia)(jia)工(gong)傾向于工(gong)序集中(zhong)(zhong)，可(ke)(ke)以(yi)減(jian)少(shao)機(ji)床(chuang)數(shu)量和工(gong)件裝夾次(ci)數(shu)，減(jian)少(shao)不必要(yao)的(de)(de)定位誤差(cha)、生產率(lv)高(gao)。對于同軸度(du)要(yao)求很(hen)高(gao)的(de)(de)孔系(xi)加(jia)(jia)工(gong)，應在(zai)(zai)一(yi)次(ci)安裝后(hou)，通(tong)過(guo)順(shun)序連續(xu)換(huan)刀來完成該同軸孔系(xi)的(de)(de)全(quan)部加(jia)(jia)工(gong)，然后(hou)再加(jia)(jia)工(gong)其他位置的(de)(de)孔，以(yi)消(xiao)除重復定位誤差(cha)的(de)(de)影響(xiang)，提高(gao)孔系(xi)的(de)(de)同軸度(du)。

        按加工(gong)(gong)部(bu)位(wei)(wei)相對(dui)于對(dui)刀(dao)點(dian)(dian)的(de)(de)(de)距離(li)(li)大小(xiao)而言(yan)，在一(yi)(yi)般情況下，離(li)(li)對(dui)刀(dao)點(dian)(dian)近的(de)(de)(de)部(bu)位(wei)(wei)先(xian)(xian)加工(gong)(gong)，離(li)(li)對(dui)刀(dao)點(dian)(dian)遠(yuan)的(de)(de)(de)部(bu)位(wei)(wei)后(hou)加工(gong)(gong)，以便縮(suo)短刀(dao)具移動距離(li)(li)，減少空行程時(shi)間。對(dui)于車(che)削而言(yan)，先(xian)(xian)近后(hou)遠(yuan)還有(you)利于保持胚件或半成品的(de)(de)(de)剛性，改善其(qi)切削條(tiao)件。對(dui)于既(ji)有(you)銑(xian)(xian)平(ping)面(mian)又(you)有(you)鏜孔(kong)(kong)的(de)(de)(de)零件的(de)(de)(de)加工(gong)(gong)中，可(ke)按先(xian)(xian)銑(xian)(xian)平(ping)面(mian)后(hou)鏜孔(kong)(kong)順序進行。因為銑(xian)(xian)平(ping)面(mian)時(shi)切削力較大，零件易發生變形，先(xian)(xian)銑(xian)(xian)面(mian)后(hou)鏜孔(kong)(kong)，使其(qi)有(you)一(yi)(yi)段(duan)時(shi)間恢復，待其(qi)恢復變形后(hou)再鏜孔(kong)(kong)，有(you)利于孔(kong)(kong)的(de)(de)(de)加工(gong)(gong)精度，其(qi)次，若先(xian)(xian)鏜孔(kong)(kong)后(hou)銑(xian)(xian)平(ping)面(mian)，孔(kong)(kong)口(kou)就會產生毛刺、飛(fei)邊，影響孔(kong)(kong)的(de)(de)(de)裝配。