為(wei)(wei)了(le)使加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)面(mian)不留退(tui)(tui)(tui)刀(dao)(dao)(dao)痕，主(zhu)(zhu)(zhu)軸(zhou)(zhou)(zhou)不讓(rang)(rang)刀(dao)(dao)(dao)，工(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)讓(rang)(rang)刀(dao)(dao)(dao)。 主(zhu)(zhu)(zhu)軸(zhou)(zhou)(zhou)定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)就(jiu)是要(yao)(yao)求(qiu)加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)完(wan)了(le)，鏜(tang)(tang)桿(gan)停(ting)止旋(xuan)轉(zhuan)(zhuan)，并使鏜(tang)(tang)刀(dao)(dao)(dao)朝著(zhu)固(gu)(gu)定(ding)(ding)(ding)方(fang)(fang)(fang)向(xiang)(xiang)(xiang)(xiang)。主(zhu)(zhu)(zhu)軸(zhou)(zhou)(zhou)定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)方(fang)(fang)(fang)案(an)(an)有(you)幾種：（1）當被加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)的(de)(de)加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)表(biao)面(mian)不允許留有(you)退(tui)(tui)(tui)刀(dao)(dao)(dao)痕跡(ji)，從生(sheng)產率來考慮不能采取(qu)(qu)以工(gong)(gong)(gong)(gong)(gong)(gong)(gong)作進給速(su)度退(tui)(tui)(tui)回時(shi)，則可采取(qu)(qu)主(zhu)(zhu)(zhu)軸(zhou)(zhou)(zhou)定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)，并使工(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)“讓(rang)(rang)刀(dao)(dao)(dao)"退(tui)(tui)(tui)出(chu)的(de)(de)方(fang)(fang)(fang)案(an)(an)。（2）在加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)多層壁箱體同(tong)直(zhi)徑(jing)同(tong)軸(zhou)(zhou)(zhou)孔系時(shi)，為(wei)(wei)了(le)使鏜(tang)(tang)刀(dao)(dao)(dao)能通過(guo)待加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)孔，而送(song)(song)到接近各加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)部(bu)位，需(xu)把工(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)抬起(qi)（或降低(di)）一個高度，鏜(tang)(tang)桿(gan)定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)，使鏜(tang)(tang)刀(dao)(dao)(dao)朝上（或朝下），則可送(song)(song)進工(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)，然(ran)(ran)后(hou)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)落下并定(ding)(ding)(ding)位加(jia)壓，鏜(tang)(tang)桿(gan)旋(xuan)轉(zhuan)(zhuan)進行切削加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)。最后(hou)，鏜(tang)(tang)桿(gan)停(ting)止轉(zhuan)(zhuan)動(dong)(dong)，定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)退(tui)(tui)(tui)出(chu)。（3）當加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)內(nei)孔直(zhi)徑(jing)稍大于外面(mian)孔時(shi)，為(wei)(wei)了(le)自動(dong)(dong)送(song)(song)進鏜(tang)(tang)刀(dao)(dao)(dao)，要(yao)(yao)采取(qu)(qu)主(zhu)(zhu)(zhu)軸(zhou)(zhou)(zhou)定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)方(fang)(fang)(fang)案(an)(an)。（4）當需(xu)要(yao)(yao)加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)的(de)(de)相鄰孔很近、或者孔距箱體壁很近時(shi)，采用轉(zhuan)(zhuan)動(dong)(dong)導(dao)(dao)向(xiang)(xiang)(xiang)(xiang)件(jian)有(you)困(kun)難(nan)而必須用固(gu)(gu)定(ding)(ding)(ding)導(dao)(dao)向(xiang)(xiang)(xiang)(xiang)件(jian)，鏜(tang)(tang)刀(dao)(dao)(dao)又需(xu)要(yao)(yao)通過(guo)導(dao)(dao)向(xiang)(xiang)(xiang)(xiang)件(jian)的(de)(de)時(shi)候，則可在固(gu)(gu)定(ding)(ding)(ding)導(dao)(dao)向(xiang)(xiang)(xiang)(xiang)件(jian)上開設引導(dao)(dao)槽(cao)，使鏜(tang)(tang)桿(gan)上的(de)(de)鏜(tang)(tang)刀(dao)(dao)(dao)定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)送(song)(song)進后(hou)，再(zai)轉(zhuan)(zhuan)動(dong)(dong)導(dao)(dao)向(xiang)(xiang)(xiang)(xiang)件(jian)加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)。 主(zhu)(zhu)(zhu)軸(zhou)(zhou)(zhou)定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)控(kong)制(zhi)方(fang)(fang)(fang)式有(you)兩(liang)種：普通電動(dong)(dong)機(ji)———電動(dong)(dong)機(ji)停(ting)轉(zhuan)(zhuan)，慢(man)速(su)反轉(zhuan)(zhuan)，主(zhu)(zhu)(zhu)軸(zhou)(zhou)(zhou)定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)；變頻(pin)電動(dong)(dong)機(ji)———變頻(pin)降速(su)，主(zhu)(zhu)(zhu)軸(zhou)(zhou)(zhou)定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)。為(wei)(wei)實現工(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)“讓(rang)(rang)刀(dao)(dao)(dao)"，在移動(dong)(dong)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)作臺的(de)(de)兩(liang)端(duan)均布置(zhi)小油缸。在加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)完(wan)了(le)、刀(dao)(dao)(dao)具(ju)停(ting)止旋(xuan)轉(zhuan)(zhuan)并定(ding)(ding)(ding)向(xiang)(xiang)(xiang)(xiang)后(hou)，利用移動(dong)(dong)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)作臺帶動(dong)(dong)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)慢(man)速(su)移開端(duan)部(bu)小距離，使加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)表(biao)面(mian)離開刀(dao)(dao)(dao)尖(jian)然(ran)(ran)后(hou)退(tui)(tui)(tui)刀(dao)(dao)(dao)，這樣不僅不留下退(tui)(tui)(tui)刀(dao)(dao)(dao)痕跡(ji)，而且有(you)利于提高加(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)精度。
