Chris Radek wrote: > On Mon, Oct 06, 2008 at 01:01:25PM +0200, Geert De Pecker wrote: >> For the Z, velocity is 4 (guess 4mm/sec) and accelleration is 3. > > This means it takes 1.3 seconds to get to full speed and another 1.3 > seconds to stop again. You probably cannot thread with such a low > acceleration. > > After updating to 2.2.6 try making sure your acceleration is set as > high as possible. >
To be precise, it means you cannot thread quickly, or cut coarse threads. For the specific example you quoted, a 0.2mm thread pitch at 120 RPM, the Z axis needs to move at 120 * 0.2 / 60 = 0.4 mm/sec. At 3mm/sec^2 accel it will take 0.133 seconds to accelerate, and the spindle will turn 0.267 revolutions in that time. That is fine. But 0.2mm is a very fine thread, and 120RPM is a very slow speed. A more realistic thread is M6 x 1.0. That is 6mm diameter by 1mm pitch. For a modest cutting speed of 10m/min, you would like to be able to set the spindle speed to 530 RPM. That would require a Z axis travel of 530RPM * 1.0mm pitch = 530mm/min = 8.8mm/sec, which is more than twice what your Z can do. At 3mm/sec^2, it would take almost three seconds and 13mm to accelerate to that speed. Regards, John Kasunich ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
