Kirk Wallace wrote: > On Sat, 2008-05-24 at 13:49 -0400, [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. >> >> Thanks for looking, Martin. >> >> ______________________________________________________________________ > I have the same issue with my Hardinge. I had to turn the axis > acceleration settings in my .ini file up. Then allow some settling space > (air threading) before the thread start. >
Some "air threading" is needed, and has you have observed, the lower the accel limits of your machine, the more space you need. With a manual lathe, when you close the half-nut the carriage pretty much "instantly" is up to speed. With a CNC lathe the motor, screw, and carriage need some time to accelerate to match the spindle. In general, your acceleration limits should be as high as possible, within the limits of your machine. Too high and you risk missing steps (on a stepper machine) so of course you have to test to find the limits and then leave some margin. But don't set the acceleration limits low without a good reason. Regards, John Kasunich ------------------------------------------------------------------------- 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
