Error in 2D pocketing

[tikka308]

I created the attached G-Code with 2D pocketing in BobCad V22. The Code verifies just fine in the simulation.

However, when I inport into Mach 3 (I'm using the Mach 3 post in BCC), I get the error "Cannot change units with cutter radius compLine 7 " (that line reads: N01 G20 G40 G49 G54 G80 G90)

I don't understand the error. Can anyone help me out? Even though the error is in Mach 3, something tells me my problem is stemming from BobCad tooling path, settings, etc...

I'm attempting to mill with a 1/4" 2-flute end mill on a TAIG.

Thanks!

John

[tobyaxis]

I created the attached G-Code with 2D pocketing in BobCad V22. The Code verifies just fine in the simulation.

However, when I inport into Mach 3 (I'm using the Mach 3 post in BCC), I get the error "Cannot change units with cutter radius compLine 7 " (that line reads: N01 G20 G40 G49 G54 G80 G90)

I don't understand the error. Can anyone help me out? Even though the error is in Mach 3, something tells me my problem is stemming from BobCad tooling path, settings, etc...

I'm attempting to mill with a 1/4" 2-flute end mill on a TAIG.

Thanks!

John

The actual problem is in the Post Processor. You need it to insert N01 G20 G40 G49 G54 G80 G90.

I do not use Mach 3 but can try to help you with the post processor. Do you have a working G-Code file that you can post??

[tikka308]

Toby,

I've attached a working G-code file. Thanks!

[tikka308]

Sorry, here's the attachement

[tobyaxis]

I back plotted your file but what I originally ask for was a working G-Code file. In other words a File not created in BobCad/Cam that has your Machine/Control Specifications.

Without knowing what your Machine Control accepts, editing the Post Processor is more difficult, if not impossible.

As for the way you machined this part I suggest using the Pocket with Islands Function for Roughing it out (Bull End Mill). Then Finish the pocket with a smaller tool (Bull End Mill). The Radii at the top of the Island/Boss can be machined with a Radius Form Tool.

Does your machine have an Automatic Tool Change???

[tikka308]

Toby,

I'm actually just trying to face off this part (not actually pocket it). I was using the pocket function because I wanted the toolpath to follow the curves (i.e. just face off the material vs. cutting air on the 4 corners). I think the problem is that because I'm using a pocket function, it can't cut the corner angle I'm demanding (i'm going to try and fillet that angle in a minute...).

Is there a better way to face off odd-shaped material? The "facing" function in BobCAD seems to only cut rectangular shapes.

Thanks.

BTW - I've got a TAIG Mill, so no ATC. I'm just learning though, so I don't mind changing bits, etc.

What is a radius form tool?

Thanks.

[The One]

John,

All you really need to do is move the 'G40 G49 G54 G80' to another line. The error says it all.

You can not issue a G20 on the same line as the G40 and G49. I am suggesting to move the other commands so that there aren't other issues when you try to run this.

Call BobCAD and tell them what you need. Try my suggestion first and if that fails to yeild a productive result let me know.

Regards

[tikka308]

The One - thanks. I'll give that a try as well as start doing some homework on the G-code commands.

Cheers!

[tobyaxis]

The One - thanks. I'll give that a try as well as start doing some homework on the G-code commands.

Cheers!

G20= Inch Programming
G40= Cutter Compensation Cancel
G49= Height Offset Cancel
G54= Work Coordinate G54-G59 and G54.1 P01-G54.1 P300
G80= Drill Canned Cycle Cancel
G90= Absolute Coordinate Programming

If Mach is following Fanuc and Yasnac based Controls

[sorincnc]

Crazy question, but why use a pocket function to face of the material and not a "face" function???? It seem to me that it will be much easier to do that. I also agree that you need to call tech support and let them know that there needs to be a change in the post.

[tobyaxis]

Crazy question, but why use a pocket function to face of the material and not a "face" function???? It seem to me that it will be much easier to do that. I also agree that you need to call tech support and let them know that there needs to be a change in the post.

Hey how are you??? Haven't seen you around lately. Nice to see you

tikka308, is trying to Face an irregular Shape like the bottom of a Pocket or a Face with Bosses on it. Any ideas on how to do this in V22? I really don't do much 2D machining with this New Version, mostly 3D and 4 Axis. But I think using the pocket function is a good way to handle this particular task.

Cheers!!!!

[tikka308]

Toby - Thanks for hopping in. You're exactly right - I'm trying to face an irregular shape - something I imagine happens quite often... I want to avoid cutting air, so I was going to pocket the part with no side-profile finish pass.

I'm not sure why the error is happening (as a newbie, I've had my plate full with CAD/CAM and don't know g-code yet). But I believe the error is a result of me trying to tell BobCAD/CAM to mill a corner that it cannot based on the tool radius. I say that because I was trying to pocket a very sharp corner with a 0.375" cutter. The error went away when I either filleted it or (even better) offset the profile by 0.375/2.