FULL ARC ( flowline)

[wfcPain]

Ok... I have a simple flowline toolpath.Milling a chamfer on a slot.

The flowline data is correct,the surface normals are correct.

It backplots fine and im using a cnc editer to backplot the nc code,it looks fine.

 

Running a fanuc controller, the tool does a full 360 deg circle instead of the 180 deg arc on the ends.

It only does this on one of the 14 chamfers that i am milling.

As it steps down , it seems to do this random 360 arc and continue along the chamfer surface.

 

 

Any idea where to begin looking?

[Teh Bear without Brains kinda idiot]

Use arcs break in control definitions and no full circle allowed

[Chris Rizzo]

Does it actually gouge the surface?

[wfcPain]

Arc break is used in control def. and the "allow full arc" is unchecked

 

 

It doesnt gouge the part because it arcs inside the slot

[Hardmill]

Ive seen this related to the arc tol in the parameter settings of your control .

Bad things can happen if it goes the opposite way obviously

 

 

 

 

 

 

 

 

 

 

 

 

PEACE

[yorx57]

I have ran into what sounds very similar. I had the control definition set to break arcs at 180 and no full circles. In my case I was using R and not I,J,K. The problem ended up being that any arc that was 180 would output R and the next output would be -R and the next R etc. It was hit and miss on how the controller would handle the wrong -R output.

[Teh Bear without Brains kinda idiot]

can be related to filtering

if you use filter turn in one way filtering

[MrFish]

Make sure your post is outputing IJK, not R's . R can cause some problems with some controlers.

[Newbeeee™]

Make sure your post is outputing IJK, not R's . R can cause some problems with some controlers.

Is this a general statement for everything? I remember reading (possibly here) that IJK are more accurate where R is more an approximation in some circumstances?

We run R on all of our machines and have never (yet) had a problem...

Thanks

[wfcPain]

A search of the nc code found no R's

I'm running i,j, and k's.

I checked the "one way filtering" in the total tolerance.

I reposted and did a file compare with the original file and saw no differences.

 

Is there a setting on the fanuc controller that could be changed?

 

Maybe a post setting?

[Matthew Hajicek - Singularity]

I had this last week surfacing around the end of a rib with a Surface Finish Contour. My arcs were set to break at 180, outputting IJK. One of the hundreds of passes decided not to stop at the 180° point but continue to complete a circle, gouging the part. There was also a section on another rib where the tool took a shortcut across about 45° of the arc for about 30 consecutive passes, also gouging the part. So we welded the thing up, I set break arcs to 90°, carefully inspected the backplot and verify finding no errors, carefully inspected the path in NcPlot finding no errors, and tried again. The full circle was eliminated but the 45° shortcut remained.

[Teh Bear without Brains kinda idiot]

Matthew

this setting can be related

I personally scrapped mold edges once when was doing surface contour and turned it off

~~~~~~~~~~~~~~~~~

Advanced settings dialog box

 

 

 

Advanced Settings determine the tool motion on the edges of surfaces and solids, and the accuracy (tolerance) of tool motion on sharp corners. You can also perform checks for hidden solid faces and sharp internal corners on surfaces.

 

Check for internal sharp corner

 

A surface with a sharp internal corner (a ridge) may lead to a toolpath that causes gouges. Sometimes, through data exchange, surfaces may be imported to Mastercam that contain internal sharp corners. Select this option to check for sharp internal corners. Mastercam notifies you with a warning message if it encounters a sharp corner in the surface, and recommends that you remodel the surface.

[Oscar R.]

+1^

That would have been my guess. Any overlapping surfaces or shap corners would most likely cause that behavior. Had that happen to me a few times.

Only thing that doesn't make sense is that wfcPain say his backplots look good, both in MC and with an editor. Not that those are bulletproof, but still makes you wonder.

[Matthew Hajicek - Singularity]

Only thing that doesn't make sense is that wfcPain say his backplots look good, both in MC and with an editor.

Same with mine. Mastercam backplot and verify both looked good, as well as NcPlot backplot on the gcode. I'm going to have to look into the arc tolerance settings on the machine.