Remove the initiative height that stops to point to knife of advance and retreat highly. In the program in the begining, cutting tool will arrive first this one height, it is at the same time after program end, cutting tool also goes to go back this one height. Height stops to be more than since or be equal to safe height, safe height also calls the height that carry a sword, it is to shun work of cutting tool collision and the height of set (Z is worth) . Safe height is to be in milling process, when cutting tool needs to change the position fall back on interpolation of G00 of travel of reentry of this one height arrives position of below one feed, the greatest height that this value should be more than a spare parts usually (namely the highest surface of prep above spare parts) . Slow fast next knives are relative value normally relative to the distance, cutting tool issues a knife to arrive quickly with G00 appoint the position, machine the position with be close to the knife below speed to arrive next. If not set should is worth, cutting tool issues a knife to arrive directly with the speed of G00 treatment position. If this position is inside workpiece or on workpiece, and use perpendicular means leaving a sword, extremely insecure. Even if the knife below vacant position, use this value to also can make the machine tool has amortize process, ensure place leaving a sword reachs the designated position the accuracy of buy, but this value is unfavorable also obtain too big, because issue a knife to insert speed,often compare slow, too long slow fast distance leaving a sword machines the influence efficiency. In machining a process, when cutting tool need moves between 2 o'clock and not when cutting, whether should carry a knife to arrive safe plane? It is when set carry when the knife, cutting tool will raise safe plane first, move on safe plane again; Will move between 2 o'clock directly otherwise and do not carry a sword. Direct shift is OK and economic carry knife time, but must want to notice safety, there cannot be bulgy place in mobile method, special attention is in process designing, when when divisional region the choice machines curved surface and partition is machined, whether does the part that did not select among have the share of course of shift of prep above cutting tool. When rough machining, normally to the treatment of larger area the proposal is used carry knife, so that adding man-hour to be able to pause, undertake checking to cutting tool. And when finish machining, often use do not carry the knife machines speed with accelerating, resemble the treatment of corner part especially, carry the knife will cause handling time to be lengthened considerably. In aperture treatment loop, use G98 will carry the knife undertakes transferring to safe height, and use G99 will move directly, do not carry the knife arrives safe height, following plan institute are shown. Graph CNC MillingCNC Machining