Gentlemen, I believe there will be the same amount of cutting forces generated during climb milling and conventional milling. I believe the climb milling cutting forces are proportionately more on the holding axis. I have seen the Y axis overheat during an X axis move. The Y axis must 'maintain' position against the cutting forces. Doing this without movement generates heat within the motor especially for a linear guide machine that has almost no friction losses on the axis movement. The reason to choose one type of cut over another is tool life and machine finish. Sometimes the only way to determine the best type for a particular situation is to try both. Climb milling IS generally better but it can be very surprising and enlightening. thanks Stuart
On Mon, Jun 8, 2009 at 7:25 PM, Douglas Pollard<[email protected]> wrote: > Andy Pugh wrote: >> 2009/6/9 Frank Tkalcevic <[email protected]>: >> >>> How much "backlash" would the rubber teeth on the belt contribute? >>> >> >> "Some" I guess. Though it might matter less than you think. In fact, >> that thought has been occurring to me throughout this thread. There >> has been a lot of concern over absolute accuracy, when repeatability >> is probably more important in the real world. I can't think of many >> things where dimensions over a couple of feet have been important to a >> few thousandths, and in cases where they are, if the two parts are >> made on the same machine then they will fit anyway. (And it has been >> a source of some frustration to me watching machinists fretting over >> the last n-th of accuracy on a part I wanted yesterday, and where I >> have specified +/- 5mm "I don't care" accuracy. ) >> >> Similarly with a resilient belt or "springy" ballnut, it will always >> sit in the same place for the same cutting force, so if you have a >> light finishing cut you will probably get better accuracy than the >> ballscrew spec suggests. (or even if you have a consistent roughing >> cut) >> >> You will, however, probably get more chatter and vibration, but then a >> visco-elastic element might damp vibration that would be there in a >> fully rigid system. >> >> (Note, I am not a machinist, I am not even really an engineer, but I >> play one on the internet) >> >> > I seems to me that there is little or no pressure on the screw or belt > when roughing because you are generally climb milling. If there is to be > a load on the belt or screw it will be when finishing when you are > usually conventional milling or when excellerating and decelating. Any > load there will be on screw or belt is when the cutter tries to pull > itself into the work. I think this may be where a screw has an > advantage. A good machinist climbemills as much as he can to take the > load off the gearing. This assumes a climb milling attachment on a > manual machine. > Doug > > ------------------------------------------------------------------------------ > Crystal Reports - New Free Runtime and 30 Day Trial > Check out the new simplified licensing option that enables unlimited > royalty-free distribution of the report engine for externally facing > server and web deployment. > http://p.sf.net/sfu/businessobjects > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > > -- you can lead a person to knowledge but you cannot make him think ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
