On Wednesday 10 October 2007, Jon Elson wrote: >Alan Condit wrote: >> Hi all, >> >> I am trying to figure out Cutter radius compensation. And everything >> I try seems to be wrong. The example in the manual even reports >> "Concave corner with cutter radius comp". I have written a short >> program to cut the outline of a gate handle and it reports Cutter >> gouging with cutter radius. Can someone take a look at it and tell >> me what I am doing wrong. T4 is a 1/4" cutter. >> >> (GateHandle) >> G17 G20 >> G00Z3.0 >> T4 M06 >> G01 G40 X0.0 Y-0.8 F50.0 >> G01 G41 D4 X0.0 Y-0.4 (COMP LEAD IN) >> G01 X0.0 Y0.0 F50.0 (real start of part) >> Z2.5 >> G01Z2.25F25.0 > >What line does it croak on? Just for a different perspective, >here's something I wrote years ago. I have used this as my own >reference example whenever I need to figure it out again. > >http://www.timgoldstein.com/cad_cam/diacomp.htm > >When in doubt, I would put a ballpoint pen in the spindle and a >sheet of paper on the vise, and run the program, first with a >zero-diameter tool, and then again with the correct tool >diameter in the tool table. You will note that the lead-in and >lead-out points were chosen so if the part extended that far it >would have gouged the corner a little. This is to prevent EMC >from complaining about the radius of the inside corners. > >I see your program uses the I,J form of arc specification, and >only 3 fractional digits of precision. That can cause errors >even without the radius comp turned on. I always use the R form >for arcs, because there can be no roundoff error that makes the >starting and ending radius appear different. The I,J form >over-constrains the arc, and any roundoff error makes in >impossible to create any circular arc that meets the specified >coordinates. > >Jon
Which probably explains why I've never been able to make the I,J format work reliably here Jon. I'd always figured 3 places was close enough for the girls I go with. :) Thanks, next time I code something up that needs it, I'll try letting emc calculate it, which might give enough places. That last sentence would do well to find its way into the G2/3 section of the manual. I would change 'makes in impossible' to 'makes it impossible' though :) >------------------------------------------------------------------------- >This SF.net email is sponsored by: Splunk Inc. >Still grepping through log files to find problems? Stop. >Now Search log events and configuration files using AJAX and a browser. >Download your FREE copy of Splunk now >> http://get.splunk.com/ >_______________________________________________ >Emc-users mailing list >[email protected] >https://lists.sourceforge.net/lists/listinfo/emc-users -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) "In matters of principle, stand like a rock; in matters of taste, swim with the current." -- Thomas Jefferson ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
