[EMAIL PROTECTED] wrote: > Hello. > Has anyone managed to set a screw cutting lathe up successfully with > EMC2? > Mine is a simple setup. The encoder has 1ppr and also a disk with 48 > slots. The problem is that the lathe carriage does not synchronise with > the spindle nicely - it overshoots and undershoots and by the time it > settles down the thread is half cut. This happens at any speed above > about 100rpm. Other movements are beautifully smooth. I have set up lathe-type threading on my mini-mill, with a real quadrature encoder on the spindle. It has 1728 lines, for 6912 quadrature counts/revolution. So, at 100 RPM, it provides 11,520 counts/second, or 11.52 counts/servo period, assuming a 1 KHz servo update cycle. I didn't think I needed that kind of resolution or count rate, it was just a one-of-a-kind encoder I had laying around. I did also see some of this "hunting" behavior when I first started setting this up several years ago. I just dug through the EMC-users and developer's lists, but I can't find the message. I had problems in my encoder counter card that occasionally failed to perform the find index pulse function correctly, and that may have been the reason for the axis hunting. Also, if your Z axis is asked to sync to the spindle in too short a distance, it will reach its accel limit and suffer some hunting. A fine-pitch thread will be much easier to sync to than a coarse one. What is your accel limit set to in the ini file - both in the [TRAJ] section and the [AXIS_2] section (for the Z axis)?
Jon ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
