Reply with QuoteThe radius is not B. It is R.
Command structure:
G2 (G3) X.Y.Z. R. F.;
G-Code Tool compensation question
I have a fairly simple pocket shape that I am trying to mill.
I am using a 12mm tool, and the actual tool diameter set in the machine is 11.7mm.
Clearly the corners I have shown as square will be round but the drawing is just an illustration.
My issue comes when writing the G-code for the operation.
The shorter horizontal movement across the top finishes short when I put in the dimensions I would have thought it wanted.
Whys would this be - is my code just wrong?
N0080 G00 Y0 X0
N0090 G01 F=4000 Z8
N0100 G42 F=4000 Y-24
N0105 G01 X-50
N0110 G01 Y0
N0130 G01 X-31
N0135 G03 X-25 B6
N0160 G01 X25
N0175 G03 X31 B6
N0180 G01 X50
N0190 G01 Y-24
N0200 G01 X-50
N0360 G01 G40 X0
N0370 G00 Z0
Is there an issue in going from a circular move to a straight with no Y move?
I am dealing with a purpose made machine and have no manuals or knowledge of the G-Code flavour being used I am assuming the B is the Radius but have not seen that before either.
Can anyone please help - I am assuming this is something I am doing wrong so do not be shy to tell me!!
I would like to understand the logic used to do the G42 compensation if this is where the issue is.
Thanks
Similar Threads:
re: G-Code Tool compensation question
The radius is not B. It is R.
Command structure:
G2 (G3) X.Y.Z. R. F.;
Thanks for the reply - I have never seen B used before either but it seems to be correct for this version. I have tested it by making it negative and got the result the same as making R negative.Originally Posted by Samacxanh
My only other thought was whether B is some sort of alternative to I,J, K?
Anyone seen that before?
I can make the prog run fine by adding a 1mm y move between the G03 and the X moves but I don’t understand why the X move finishes short without it?
re: G-Code Tool compensation question
For one you might want to use G41 instead of G42 and go around the other way so you can climb cut instead of conventional.
You call Right Cutter Compensation G42 but you don't include an offset number Like D1 for tool one or D2 for tool 2 etc. Does this control not require an offset call when turning on cutter compensation?
Re: G-Code Tool compensation question
If the same geometry is programmed as an outside profile is the problem the same ?
Not knowing that control I'm taking a wild guess that it's detecting a gouge situation where the path can't find maintain tangency. Seeing as the problem corner is a radius in reality you could try programming a radius.
edit/ Oops I now spot describing a radius at N0160 creates a bit of a different problem. A little more coffee needed here to offer a solution.
Last edited by cyclestart; 05-08-2020 at 12:04 PM.
Anyone who says "It only goes together one way" has no imagination.
Hi - I should have mentioned this is a timber router and do limb milling is not what I want.
The tool offset must be coming in directly as it is a purpose built machine and the program is linked directly to the head doing the work and had a fixed tool.
Re: G-Code Tool compensation question
I can see what you mean I think...
....but if I was to add a G02 radius move before the G03 radius move then what dim would I put into the prior X move on line N0160? Presumably 25 less the radius of the next move.
I really just don't understand the logic being used for the tool compensation. To me, before executing the N0160 it should be looking ahead to the next move and finding the vector of the tangent to the G03 move, this then will dictate the finishing position of the X move as the workpiece dim given less the tool rad as the tangent will be just the same as if it was a G01 in the Y direction
The program give me the shape I want if I put in a dim of 31mm instead on the 25mm on line N0160.
Very Strange
