AnsweredAssumed Answered

Need to slow end-mill down

Question asked by William Finch on Nov 19, 2018
Latest reply on Dec 8, 2018 by Ajay Kumar Ranganathan



I am an instructor trying to integrate Solidworks CAM into my student-shop "workflow".  We have several inexpensive, benchtop, CNC, imported mills.  They're beefier than a Shapeoko, by far, but still pretty flexible.  The axes are driven by steppers with a TinyG controller.  So, the feed rate is limited not by the tool, I think, but by the machine.  If we run above 10 - 20 ipm, depending on material and cut, we start losing steps and the everything goes to *&#&$^@#* fairly quickly.


So, I'm trying to limit the feed parameters of an HSS end mill I entered into the Technology DB. I change the spindle speed to 3000 RPM and the feed per tooth to 0.0005, which should give about 6 in/min for a four-flute end mill. I found a post-processor for a Laguna router, which should match pretty well with the TinyG.  But, when I "post-process" the GCode sets the spindle at 12,000 rpm, the depth of a roughing pass is about 0.043, and the feed rates for cutting (G1, etc.) are about F31 for plunge and F124 for cut.


What I want is:  3000 RPM, about 0.025 depth for a rough cut, and a feed rate of about 10 ipm.  (I'm beginning to suspect this is a simple, newbie question...)


How do I force the post processor to use these values?