Chris Morley wrote: > I am not an expert, just interested. I don't follow your reasoning. > Jerk limiting is about having the TP ask for movement that is possible > for the machine to actually produce. > infinite jerk is impossible for a machine to produce movement for. > While we can ignore it in relatively slow and small machines, I can not > see why you would want to turn it off in some cases. > G33 (lathe threading) assumes the spindle is mostly maintaining constant velocity. G33.1 (rigid tapping) assumes the spindle reverses fairly quickly at a certain point. The Z axis must follow the spindle quite closely, or it will break small taps and muck up the thread on larger ones. > It seems if you have the TP request infinite jerk, then you are must realize > that your are asking the machine to NOT follow the TP command for a small > instant. > I don't see how G33.1 is any different then other machine movements. > Other than spindle synched moves, ALL axes are under TP command, and that should always keep them synched so they are all at the correct coordinated position. With a spindle-synched move, the tool must follow the spindle, which often is NOT a servo axis, and is just generally obeying a velocity command. When the G33.1 gets to the point of reversing the spindle, it can reverse fairly quickly, depending on the particular machine setup, and the Z BETTER keep up with however fast it reverses! Having any interpolation, jerk limiting, etc. between the spindle encoder and the Z axis would apply strain to the tap, and be very undesirable.
Jon ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
