[How do I?] Mach 3 Work Offset

[TomS]

See if this DXF is any different. I didn't create a TAP or NC file because I don't what the cutting parameters are.

Thanks for your help Jim. Unfortunately it didn't work. Same thing happened: selected the first, third and fifth parts on the drawing, clicked offset and the third and fifth parts disappeared. I input a smaller cutter (1/8") but still a no go.

I think it was jumps4 (Steve) that said D2NC will not do islands. That may be what the program is telling us. I'm going to study a bit more on offsets and see if I can get them working.

Tom S.

 

[TomS]

Here is another DXF with 8 parts in the same footprint. There is > 0.5 between them.

You are persistent! LOL

I tried it and still the same. Tried various size cutters (1/16", 1/8", 1/4", 3/8", 1/2") and in all instances 2 or more parts disappeared from the screen.

Tom S.

 

[TomS]

You are not going to believe this but I was successful in getting D2NC to offset three of the six parts on my original drawing. But it only works by inputting a 1/4" cutter. If I input a 1/16" or 3/8" cutter one or two of the parts disappear. Ran a simulation and it appears to be working.

The only difference was I downloaded the latest version of D2NC. I read through the updates but didn't see anything relating to the problems I was having.

I'm out of town until middle of next week so I won't be able to test it on the mill until then. Hope it works. I'll keep you posted.

Thanks again to everyone for your help.

Tom S.

 

[JimDawson]

That is crazy. I think I would try another CAM program. Looking forward to seeing the result.

 

[TomS]

That is crazy. I think I would try another CAM program. Looking forward to seeing the result.

It's enough to drive you to drink. Now that's an idea!

I see you use CamBam. I'll start there.

Tom S.

 

[JimDawson]

I see you use CamBam. I'll start there.

At least I can help you with it, been using it for about 3 (4?) years

 

[chevydyl]

For info the parts are 1/2" away from each other at their nearest point. I'm using a 3/8" end mill so it should have space to clear the adjacent part.

Tom S.

I get that, but when you said you have an offset of 11.5 inches MAYBE its interpreting it as cutter offset, (cutter comp) and removing the parts that wont survive a giant cutter like that the way it is nested. idk, just a thought cause cutter offset sounds similar to what cutter comp does

 

[TomS]

I get that, but when you said you have an offset of 11.5 inches MAYBE its interpreting it as cutter offset, (cutter comp) and removing the parts that wont survive a giant cutter like that the way it is nested. idk, just a thought cause cutter offset sounds similar to what cutter comp does

I set cutter offset in my CAM program and work offset in Mach 3. It's the CAM program that's making the parts disappear whether I'm using G54, 55 or 56. I'm kinda new at CNC and trying to understand how my CAM program interprets inputs and the gcode that moves the table and spindle.

Tom S.

 

[JimDawson]

Tom, I'm a little confused here. What is ''cutter offset''? I should have asked this earlier. I'm not familiar with your CAM program, so maybe it's something you have to input when setting up.

When doing a layout, what I plug into the CAM program is the 0,0,0 point for the work envelope of the layout, cut width, and the actual tool diameter. Then when the G-code compiles, the cut path is set. All I have to do at the machine is set the work 0,0,0 point in the DRO and press Go. Mach3 has a strange setup for the work coordinates as opposed to the machine coordinates. I never really did figure that one out. IMHO, on a mill they should be the same, and you should be able to set them anywhere you want. But I don't have a lot of experience with Mach3 so maybe it's just my lack of experience.

Regarding cut width, sometimes I make the cut width > than the tool diameter so that it will make 2 passes around the profile, the final pass as a cleanup or spring cut. Normally ~ 0.005. For instance, if my cutter is 0.250, I'll set the cut width at 0.255 to give me a cleanup of 0.005 all around. So the first pass would theoretically make the part 0.010 oversize.

 

[TomS]

Tom, I'm a little confused here. What is ''cutter offset''? I should have asked this earlier. I'm not familiar with your CAM program, so maybe it's something you have to input when setting up.

When doing a layout, what I plug into the CAM program is the 0,0,0 point for the work envelope of the layout, cut width, and the actual tool diameter. Then when the G-code compiles, the cut path is set. All I have to do at the machine is set the work 0,0,0 point in the DRO and press Go. Mach3 has a strange setup for the work coordinates as opposed to the machine coordinates. I never really did figure that one out. IMHO, on a mill they should be the same, and you should be able to set them anywhere you want. But I don't have a lot of experience with Mach3 so maybe it's just my lack of experience.

Regarding cut width, sometimes I make the cut width > than the tool diameter so that it will make 2 passes around the profile, the final pass as a cleanup or spring cut. Normally ~ 0.005. For instance, if my cutter is 0.250, I'll set the cut width at 0.255 to give me a cleanup of 0.005 all around. So the first pass would theoretically make the part 0.010 oversize.

D2NC works similar to what you describe with a few differences. In my case the 0,0 point is set in your CAD drawing. For the parts I described earlier in this thread I drew a box around the nested parts and defined my X and Y 0,0 as the lower left corner. In my CAM software I select the 0,0 reference as bottom left then select Offset. For a Profile cut I select Inside or Outside and enter the cutter diameter in the Tool Diameter box then select the objects in the drawing I want to machine. The Offset function sets the edge of the cutter to the part edge. That is the cutter offset, e.g. a .375" end mill cutter offset is .1875". There are a few more steps involved to get to the point of generating gcode but this is how you get through the cutter offset steps. Hope this is as clear as mud.

Tom S.