I'm attending the CNC Workshop 2007 in Galesburg, IL. The emc
developers call it "fest". So far we've been working on Constant Surface Speed
for lathes, and I plan to work next on Feed per Revolution. Update: Feed Per Revolution is also implemented.
The photograph shows two threads cut by EMC on Chris Radek's servo lathe. The tip is cut to a hemisphere using G43 cutter shape compensation. "Once I set my tool offsets correctly, the values in the Machinery's Handbook just worked", said Chris.
Mini-documentation for CSS (subject to change, alpha-quality implentation on CVS trunk):
- G96 D-: Enable CSS with maximum spindle speed of D RPM
- G97: Enable constant RPM mode
- S-: In CSS mode and G20 (inches), program constant surface speed of S feet per minute. In G21 (metric), program constant surface speed of S meters per minute.
The center of rotation is assumed to be at the machine X=0. When G43 is in effect, the calculated tool tip location is used to determine the radius. Coordinate system offsets are not considered.
Mini-documentation for FPR (subject to change, alpha-quality implementation on CVS trunk):
- G94, G93: (existing G-codes) Select feed per minute mode or inverse time feed mode
- G95: Select feed per revolution mode
- F-: In Feed Per Revolution mode, specify the feed rate in inches or millimeters per revolution.
Feed-per-revolution uses velocity feedback on the new pin motion.spindle-speed-in, which is in revolutions per second.
(originally posted on the AXIS blog)
