.26m/min(0.804m/s)Р切削工时:РT=L+l1+l2/n×f,式中L=45,l1=4,l2=0Р∴T=45+4/230×0.6=0.36minР半精车Φ34外圆Р切削深度ap=0.45mmР进给量:因表面粗糙度Ra=0.8,rε=1.0mm。为了保证质量,查表6,f=0.2~0.3mm,按机床说明书取f=0.25mm/r。Р计算切削速度:根据表21РVc=(Cv/601-mTmapXvfyv)×Kv, 式中Cv=291,Xv=0.15,yv=0.2,m=0.2。РKv=KMv ×Ktv×Kkrv×Ksv×KTv×KKv 。其中KMv=0.637/0.735=0.87,РKtv=1.0,Kkrv=1.0,Ksv=0.8,KTv=1.0,KKv=1.0Р∴Vc=(291/601-0.2×36000.2×0.450.15×0.250.35)×0.87×1.0Р×1.0×0.8×1.0×1.0=2.21m/s(132.6m/min)Р确定主轴转速:Рns=1000v/πdw =1000×132.6/3.14×66.82=632r/minР按机床选取n=610r/min,所以实际切削速度РV=nW×dw×π/1000 Р=3.14×66.82×610/1000Р=127.99m/min (2.13m/s)Р切削工时:РT=L+l1+l2/n×f,式中L=60,l1=4,l2=0Р∴T=64+4+0/610×0.25=0.446min(26.76s)Р半精车Φ45Р切削深度ap=0.45mmР进给量与主轴转速:与Φ88.88相同,即f=0.55mm/r,n=370r/minР所以实际切削速度РV=nW×dw×π/1000 Р=3.14×46.5×370/1000Р=54m/min (0.9m/s)Р切削工时:РT=L+l1+l2/n×f,式中L=35,l1=4,l2=0
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