1．選擇基準的三個基本的要求：(1) 選擇基準應該能保證工件定位準確裝卸方便方便可靠。(2) 選擇基準與各加工部位的的尺寸計算簡單。(3) 保證加工精度。數控加工中心機床

　　2．選(xuan)擇(ze)定位(wei)(wei)(wei)基(ji)(ji)準(zhun)(zhun)6個(ge)原則：(1) 盡量的(de)選(xuan)擇(ze)設(she)計基(ji)(ji)準(zhun)(zhun)作為(wei)定位(wei)(wei)(wei)基(ji)(ji)準(zhun)(zhun)；(2) 定位(wei)(wei)(wei)基(ji)(ji)準(zhun)(zhun)和設(she)計基(ji)(ji)準(zhun)(zhun)不能(neng)統(tong)一時(shi)(shi)，應(ying)該嚴格控制(zhi)定位(wei)(wei)(wei)誤(wu)差保證加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)精度(du)(du)；(3) 工(gong)(gong)(gong)(gong)(gong)件(jian)(jian)需(xu)(xu)要兩次(ci)以上裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)時(shi)(shi)，所(suo)選(xuan)基(ji)(ji)準(zhun)(zhun)在一次(ci)裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)定位(wei)(wei)(wei)能(neng)完成(cheng)(cheng)全(quan)部(bu)(bu)關鍵(jian)精度(du)(du)部(bu)(bu)位(wei)(wei)(wei)的(de)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)；(4) 所(suo)選(xuan)基(ji)(ji)準(zhun)(zhun)要保證完成(cheng)(cheng)可(ke)能(neng)多(duo)(duo)的(de)加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)內容；(5) 批量加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)時(shi)(shi)，零件(jian)(jian)定位(wei)(wei)(wei)基(ji)(ji)準(zhun)(zhun)應(ying)盡可(ke)能(neng)與建立工(gong)(gong)(gong)(gong)(gong)件(jian)(jian)坐(zuo)標系的(de)對刀(dao)基(ji)(ji)準(zhun)(zhun)重合(he)(he)；(6) 需(xu)(xu)要多(duo)(duo)次(ci)裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)時(shi)(shi)，基(ji)(ji)準(zhun)(zhun)應(ying)該前后統(tong)一。 加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)中(zhong)心夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)的(de)確定： 1．對夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)的(de)基(ji)(ji)本要求：(1) 夾(jia)(jia)(jia)(jia)緊(jin)機(ji)構不得影響進給，加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)部(bu)(bu)位(wei)(wei)(wei)要敞開；(2) 夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)在機(ji)床上能(neng)實現定向(xiang)安裝(zhuang)(zhuang)；(3) 夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)的(de)剛性與穩定性要好(hao)。 2．常用(yong)(yong)夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)種類(lei)：(1) 通用(yong)(yong)夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)：如虎鉗、分度(du)(du)頭、卡(ka)盤等；(2) 組合(he)(he)夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)：組合(he)(he)夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)由一套結構已(yi)經(jing)(jing)標準(zhun)(zhun)化、尺寸已(yi)經(jing)(jing)規格化的(de)通用(yong)(yong)元件(jian)(jian)組合(he)(he)元件(jian)(jian)所(suo)構成(cheng)(cheng)；(3) 專(zhuan)(zhuan)用(yong)(yong)夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)：專(zhuan)(zhuan)為(wei)某(mou)一項或(huo)類(lei)似的(de)幾項加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)設(she)計制(zhi)造的(de)夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)；(4) 可(ke)調整夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)：組合(he)(he)夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)與專(zhuan)(zhuan)用(yong)(yong)夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)的(de)結合(he)(he)，既能(neng)保證加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)的(de)精度(du)(du)，裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)更具(ju)(ju)(ju)靈活(huo)性；(5) 多(duo)(duo)工(gong)(gong)(gong)(gong)(gong)位(wei)(wei)(wei)夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)：可(ke)同時(shi)(shi)裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)多(duo)(duo)個(ge)工(gong)(gong)(gong)(gong)(gong)件(jian)(jian)的(de)夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)；(6) 成(cheng)(cheng)組夾(jia)(jia)(jia)(jia)具(ju)(ju)(ju)：專(zhuan)(zhuan)門用(yong)(yong)于形狀(zhuang)相(xiang)(xiang)似、尺寸相(xiang)(xiang)近且定位(wei)(wei)(wei)、夾(jia)(jia)(jia)(jia)緊(jin)、加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)方(fang)法相(xiang)(xiang)同或(huo)相(xiang)(xiang)似的(de)工(gong)(gong)(gong)(gong)(gong)件(jian)(jian)的(de)裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)。數(shu)控加(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)(gong)中(zhong)心機(ji)床

   3．加工(gong)(gong)(gong)(gong)中心夾(jia)具(ju)(ju)的(de)(de)(de)選用原則： (1) 在保(bao)證加工(gong)(gong)(gong)(gong)精度和(he)生產效率的(de)(de)(de)前提下，優(you)先選用通用夾(jia)具(ju)(ju)； (2) 批量加工(gong)(gong)(gong)(gong)可考(kao)慮(lv)采(cai)用簡(jian)單專(zhuan)用夾(jia)具(ju)(ju)； (3) 大批量加工(gong)(gong)(gong)(gong)可考(kao)慮(lv)采(cai)用多工(gong)(gong)(gong)(gong)位夾(jia)具(ju)(ju)和(he)高效的(de)(de)(de)氣壓、液壓等專(zhuan)用夾(jia)具(ju)(ju)； (4) 采(cai)用成(cheng)組工(gong)(gong)(gong)(gong)藝(yi)時(shi)應使用成(cheng)組夾(jia)具(ju)(ju)； 4．工(gong)(gong)(gong)(gong)件在機(ji)床(chuang)(chuang)工(gong)(gong)(gong)(gong)作臺上(shang)的(de)(de)(de)最佳裝夾(jia)位置：工(gong)(gong)(gong)(gong)件裝夾(jia)位置應保(bao)證工(gong)(gong)(gong)(gong)件在機(ji)床(chuang)(chuang)各軸的(de)(de)(de)加工(gong)(gong)(gong)(gong)行程范圍(wei)內，并(bing)且使得刀(dao)具(ju)(ju)的(de)(de)(de)長度盡可能縮短，提高刀(dao)具(ju)(ju)的(de)(de)(de)加工(gong)(gong)(gong)(gong)剛性。數控加工(gong)(gong)(gong)(gong)中心機(ji)床(chuang)(chuang)