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)(xuan)擇定(ding)(ding)(ding)位基(ji)(ji)準6個原則(ze)：(1) 盡量(liang)的(de)(de)選(xuan)(xuan)擇設計基(ji)(ji)準作為定(ding)(ding)(ding)位基(ji)(ji)準；(2) 定(ding)(ding)(ding)位基(ji)(ji)準和設計基(ji)(ji)準不(bu)(bu)能(neng)(neng)統一(yi)(yi)時，應(ying)該(gai)嚴格控制定(ding)(ding)(ding)位誤差保證(zheng)加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)精度(du)；(3) 工(gong)(gong)(gong)(gong)件(jian)(jian)需要(yao)(yao)(yao)兩次以上(shang)裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)(jia)(jia)加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)時，所選(xuan)(xuan)基(ji)(ji)準在一(yi)(yi)次裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)(jia)(jia)定(ding)(ding)(ding)位能(neng)(neng)完成(cheng)全部關鍵精度(du)部位的(de)(de)加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)；(4) 所選(xuan)(xuan)基(ji)(ji)準要(yao)(yao)(yao)保證(zheng)完成(cheng)可(ke)(ke)能(neng)(neng)多的(de)(de)加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)內容；(5) 批量(liang)加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)時，零件(jian)(jian)定(ding)(ding)(ding)位基(ji)(ji)準應(ying)盡可(ke)(ke)能(neng)(neng)與(yu)建(jian)立工(gong)(gong)(gong)(gong)件(jian)(jian)坐(zuo)標系的(de)(de)對(dui)刀(dao)基(ji)(ji)準重合；(6) 需要(yao)(yao)(yao)多次裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)(jia)(jia)時，基(ji)(ji)準應(ying)該(gai)前后統一(yi)(yi)。 加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)中心夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)的(de)(de)確定(ding)(ding)(ding)： 1．對(dui)夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)的(de)(de)基(ji)(ji)本要(yao)(yao)(yao)求：(1) 夾(jia)(jia)(jia)(jia)(jia)(jia)緊機(ji)構(gou)不(bu)(bu)得影(ying)響進(jin)給，加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)部位要(yao)(yao)(yao)敞開；(2) 夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)在機(ji)床(chuang)上(shang)能(neng)(neng)實現定(ding)(ding)(ding)向安裝(zhuang)(zhuang)；(3) 夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)的(de)(de)剛性與(yu)穩(wen)定(ding)(ding)(ding)性要(yao)(yao)(yao)好。 2．常用(yong)(yong)夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)種類：(1) 通用(yong)(yong)夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)：如(ru)虎鉗(qian)、分度(du)頭(tou)、卡(ka)盤等；(2) 組(zu)合夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)：組(zu)合夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)由(you)一(yi)(yi)套結(jie)構(gou)已經(jing)標準化(hua)、尺(chi)寸已經(jing)規(gui)格化(hua)的(de)(de)通用(yong)(yong)元(yuan)件(jian)(jian)組(zu)合元(yuan)件(jian)(jian)所構(gou)成(cheng)；(3) 專用(yong)(yong)夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)：專為某一(yi)(yi)項或類似(si)的(de)(de)幾項加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)設計制造的(de)(de)夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)；(4) 可(ke)(ke)調整(zheng)夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)：組(zu)合夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)與(yu)專用(yong)(yong)夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)的(de)(de)結(jie)合，既能(neng)(neng)保證(zheng)加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)的(de)(de)精度(du)，裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)(jia)(jia)更(geng)具(ju)靈活性；(5) 多工(gong)(gong)(gong)(gong)位夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)：可(ke)(ke)同時裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)(jia)(jia)多個工(gong)(gong)(gong)(gong)件(jian)(jian)的(de)(de)夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)；(6) 成(cheng)組(zu)夾(jia)(jia)(jia)(jia)(jia)(jia)具(ju)：專門(men)用(yong)(yong)于(yu)形狀相似(si)、尺(chi)寸相近且定(ding)(ding)(ding)位、夾(jia)(jia)(jia)(jia)(jia)(jia)緊、加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)方法(fa)相同或相似(si)的(de)(de)工(gong)(gong)(gong)(gong)件(jian)(jian)的(de)(de)裝(zhuang)(zhuang)夾(jia)(jia)(jia)(jia)(jia)(jia)。數控加(jia)(jia)(jia)(jia)(jia)工(gong)(gong)(gong)(gong)中心機(ji)床(chuang)

   3．加(jia)(jia)(jia)工(gong)(gong)中(zhong)心夾(jia)(jia)(jia)具(ju)(ju)(ju)(ju)的(de)選用(yong)原則(ze)： (1) 在保證加(jia)(jia)(jia)工(gong)(gong)精度和生產效率的(de)前提下(xia)，優先選用(yong)通用(yong)夾(jia)(jia)(jia)具(ju)(ju)(ju)(ju)； (2) 批量加(jia)(jia)(jia)工(gong)(gong)可(ke)考(kao)慮采用(yong)簡單專用(yong)夾(jia)(jia)(jia)具(ju)(ju)(ju)(ju)； (3) 大批量加(jia)(jia)(jia)工(gong)(gong)可(ke)考(kao)慮采用(yong)多工(gong)(gong)位夾(jia)(jia)(jia)具(ju)(ju)(ju)(ju)和高效的(de)氣壓(ya)、液壓(ya)等專用(yong)夾(jia)(jia)(jia)具(ju)(ju)(ju)(ju)； (4) 采用(yong)成(cheng)(cheng)組(zu)工(gong)(gong)藝時應(ying)使用(yong)成(cheng)(cheng)組(zu)夾(jia)(jia)(jia)具(ju)(ju)(ju)(ju)； 4．工(gong)(gong)件(jian)(jian)在機(ji)床(chuang)工(gong)(gong)作臺上的(de)最佳裝夾(jia)(jia)(jia)位置(zhi)(zhi)：工(gong)(gong)件(jian)(jian)裝夾(jia)(jia)(jia)位置(zhi)(zhi)應(ying)保證工(gong)(gong)件(jian)(jian)在機(ji)床(chuang)各軸的(de)加(jia)(jia)(jia)工(gong)(gong)行程范(fan)圍內(nei)，并(bing)且使得刀具(ju)(ju)(ju)(ju)的(de)長度盡可(ke)能縮短，提高刀具(ju)(ju)(ju)(ju)的(de)加(jia)(jia)(jia)工(gong)(gong)剛(gang)性。數(shu)控加(jia)(jia)(jia)工(gong)(gong)中(zhong)心機(ji)床(chuang)