Radius problems when generating gcode from bobcad for mach3... ?

[scyan]

Hey guys, we're having some radius issues when generating gcode from bobcad... bobcad seems to generate its IJ in incremental mode and sometimes will get a 0 arc I ... and mach 3 doesnt like that at all. Why is bobcad doing that ?

is there a way you can set bobcad to generate absolute IJ ? would that fix it ?

Also, what are IJ exactly ? how do they work ? I notice and understand the x y and z.. but what do i and j have to do with anything ?

sorry, realllll newbie...

Thanks !

Scy

[bigj121]

Having same problems.... I and J codes are for arcs, your G02 and G03 commands. See if you can use a different postprocesor to use the R code for arcs. I am still learning also and am looking at tayloring the postprocessor to meet that need.

[Gandalf]

These are generally used to describe the centerpoint of a radius. Usually it is incremental from the startpoint. Lets say your arc center is 5 in X an 5 in Y. Your start is at X1 and Y2 your I would be 4 and your J would be 3.

[tobyaxis]

Originally Posted by scyan Hey guys, we're having some radius issues when generating gcode from bobcad... bobcad seems to generate its IJ in incremental mode and sometimes will get a 0 arc I ... and mach 3 doesnt like that at all. Why is bobcad doing that ? is there a way you can set bobcad to generate absolute IJ ? would that fix it ? Also, what are IJ exactly ? how do they work ? I notice and understand the x y and z.. but what do i and j have to do with anything ? sorry, realllll newbie... Thanks ! Scy

Originally Posted by bigj121 Having same problems.... I and J codes are for arcs, your G02 and G03 commands. See if you can use a different postprocesor to use the R code for arcs. I am still learning also and am looking at tayloring the postprocessor to meet that need.

To add to what Gandalf said. Have you tried to setup BCC to Program using "R" instead of I and J?

Also I, J, K are relative to X(I) Y(J) Z(K) respectively.

[The One]

Ultimately you have two options.

1. Configure Mach3 to accept incremental I and J.

2. Configure BobCAD to Output absolute I and J.

For option 1, I can't provide all that much help because I haven't so much as looked at Mach3 for quite a few months. I do know however that you can change the way Mach3 accepts arcs...maybe in the Config menu?

For option 2, Open the NC-CAM window. Go to 'Setup' and Click on 'Driver'. Next click on the 'ISO' tab. Just uncheck all of the options for circular motion and then Click OK. You will be outputting abs I and J in no time.

Regards

[ger21]

You need a post from BobCAD that won't output arcs with zero radius. If absolute arcs have a 0 radius, they won't work either.

[scyan]

What do you mean by a post from bobcad ? I dont understand what you mean... you mean in my driver ?

Thx all, i have some stuff to tinker now.. hehe

[ger21]

Post processor that you use to create the g-code.
http://www.bobcad.com/index.php?sele...lic_html/posts