Wow, Thanks Chad - that was a fantastic explanation for a layman like myself! I now see why my radius and length offset values weren't having any effect on the gcode, too. <:-) I'll have to check EMC to see if it supports these compensation registers - I'm guessing it must, but don't know for sure.
It had previously been suggested to me, and it may be the simplest approach, that I simply fudge the cutter size in the tool definition in DCAD - it sounds like the offset register is just another approach to the same end. What I need to experiment with is whether I get the same effective size difference under all conditions or if its more prevalent when cutting circles than lines, holes vs outside countours, climb vs conventional, etc. I've cut a number of parts previously, but this was the first time that fit on a particular feature was critical, so I may have had this happening all along and just not realized it.
BTW, the modified TurboCNC Post that you did for me has been working fine - no more issues with the arcs not mating up - Thanks!
It would be nice to add the G40, G41 and G42 capabilities to it. The Mach2 Post will output a G4x with the H register value, but not the D register value. I was going to try to copy & paste the relevant sections of the Mach2 Post to the TurboCNC Post, but given that the Mach2 output doesn't include the D register value, it may need a little further looking at by you.
Here is the gcode produced by the original, unmodified Mach2 Post for a tool selection that has the radius and length offset both set to 3 - note that a G43 is generated that provides an H value, but no D value is output anywhere:
O100
N7G00G20G17G90G40G49G80
N8Z0.25
N9G49
N10T3M06 ( End Mill )
N11G00G43Z0.25H3
N12S1000M03
N13G94
N14M08
N15S1000
N16X0.9063Y0.5
N17Z0.1181
N18G01Z-0.25F0.163
N19G03X0.5Y0.9063I0.5J0.5
N20X0.0938Y0.5I0.5J0.5
N21X0.5Y0.0938I0.5J0.5
N22X0.9063Y0.5I0.5J0.5
N23G00Z0.25
N24M09
N25M30
Here is the output of the latest TurboCNC Post that you sent me for the same program - no G4x code of any variety is produced:
G90
G20
G00 X0.0 Y0.0 Z0.25
G00
M05
M06 T03 ( End Mill )
M03 S1000
M07
M03 S1000
G00 X0.9063 Y0.5
G00 Z0.1181
G01 Z-0.25 F0.163
G03 X0.5 Y0.9063 I-0.4063 J0.0
G03 X0.0938 Y0.5 I0.0 J-0.4063
G03 X0.5 Y0.0938 I0.4063 J-0.0
G03 X0.9063 Y0.5 I0.0 J0.4063
G00 Z0.25
M02
Thanks Again for the help!!  |