Toolbert
Stainless
- Joined
- Nov 29, 2003
- Location
- Vashon Island, WA
Thanks ... Edited - I mis-spoke here and misrepresented what Jim Harvey explains in his book. For some reason it didn't make sense the first 3 times I read it but indeed he is saying to let the CAM do the cutter radius compensation and use G41 for wear. The "not my cup of tea" part refers to programming the part outline and letting the control do the radius offset.
So it's pretty much ... nevermind. Good to have a reality check.
With modern CAM providing "system compensation" for cutter radius, instead of using G41 with a radius offset in a D register, there sure is a range of opinion about the merit of using G41 at all.
Both the Jim Harvey "CNC Trade Secrets" book, and my local mentor, a 68yo lifetime cnc machinist, have a strong opinion to let the CAM compensate, use new end mills (not resharps), and never use G41. Mr. Harvey says "it's not my cup of tea" and does not elaborate further. When my mentor needs to dial in a closer diameter, he adjusts the side allowance on a feature-by-feature basis in the CAM and regenerates the gcode.
My sense is this is the attitude for expedient, lower precision work, and pretty obviously, anyone doing in-machine gaging uses G41 and regards the alternative as ridiculous.
My CAM appears to support combining system compensation for cutter radius with G41 for only a wear offset, not actual radius compensation. I.e. the D register for a cutter would have 0 for radius and a small positive or negative offset in the wear register.
Do folks actually do this? Do controls generally accept this, i.e. G41 with a 0 or negative radius cutter? Kinda wondering what the real world use of G41 is specifically for CAM generated gcode.
thanks
So it's pretty much ... nevermind. Good to have a reality check.
With modern CAM providing "system compensation" for cutter radius, instead of using G41 with a radius offset in a D register, there sure is a range of opinion about the merit of using G41 at all.
Both the Jim Harvey "CNC Trade Secrets" book, and my local mentor, a 68yo lifetime cnc machinist, have a strong opinion to let the CAM compensate, use new end mills (not resharps), and never use G41. Mr. Harvey says "it's not my cup of tea" and does not elaborate further. When my mentor needs to dial in a closer diameter, he adjusts the side allowance on a feature-by-feature basis in the CAM and regenerates the gcode.
My sense is this is the attitude for expedient, lower precision work, and pretty obviously, anyone doing in-machine gaging uses G41 and regards the alternative as ridiculous.
My CAM appears to support combining system compensation for cutter radius with G41 for only a wear offset, not actual radius compensation. I.e. the D register for a cutter would have 0 for radius and a small positive or negative offset in the wear register.
Do folks actually do this? Do controls generally accept this, i.e. G41 with a 0 or negative radius cutter? Kinda wondering what the real world use of G41 is specifically for CAM generated gcode.
thanks
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