Finish Flowline

[Hertz]

Can anyone help me with why my toolpath is moving in Z height more than it should be?

See attached test file. I am expecting the toolpath to just go back and forth with a Z and X movement after each pass, but it is adding extra micro z movements and it's causing the machine to slow right down to read it. My mill doesn't handle those moves very well so I'd like to have it not do it. I'm not sure how to stop it or why it's even doing it at all.

test flowline.mcam

[AHarrison1]

The only Z moves I'm seeing is the step down after each X step over so that the tool is stays tangent with the surface.

Is that what you are referring to?

[Hertz]

No. If you backplot the toolpath and watch the numbers, you will see extra z heights. 

I'm looking at it right now and the 2nd pass Z height goes across at Z.2441, then jumps to Z.2443, then moves in X, and then Z again to Z.2314, then comes across. It keeps doing this throughout the toolpath.

I was expecting it to go across at Z.2441, then move in X, then down to Z.2314. I don't understand what the extra z move is for(.2443) Almost seems like it's retracting for clearance but only .0002 at a time.

[AHarrison1]

Tolerance settings seem to have an effect, tightening tolerance decreased the extra Z move to .0001" at some spots.

As to why the extra jumps, I have no idea.

[Hertz]

20 minutes ago, AHarrison1 said:

Tolerance settings seem to have an effect, tightening tolerance decreased the extra Z move to .0001" at some spots.

As to why the extra jumps, I have no idea.

Yeah I noticed that as well. Unfortunately, can't get it to stop completely. This is very weird. I'm sure this wasn't an issue for me before as I've used this type of toolpath many times.

[AHarrison1]

I have just tried this in a previous version (2020) and it shows the same thing.

Maybe something for CNC Software to look into.

 

[Jake L]

If you disable (uncheck) "check gap motion for gouge" which is here: Flowline Parameters > Finish Flowline Parameters tab > Gap Settings... > Motion < Gap size, keep tool down > check gap motion for gouge then this small retract goes away.

I'm guessing this has something to do with the tolerances on the gouge check in gap motion vs flowline motion. During gap motion the tool may need slightly more clearance to classify a motion as not a gouge, whereas in the flowline motion the tool wants to be in contact with the part to cut the surface. That's just a guess though.

When I see little motions like that, usually disabling one of the gouge checks fixes it, you just have to manually gouge check which can be dangerous.

[Hertz]

2 hours ago, Jake L said:

If you disable (uncheck) "check gap motion for gouge" which is here: Flowline Parameters > Finish Flowline Parameters tab > Gap Settings... > Motion < Gap size, keep tool down > check gap motion for gouge then this small retract goes away.

I'm guessing this has something to do with the tolerances on the gouge check in gap motion vs flowline motion. During gap motion the tool may need slightly more clearance to classify a motion as not a gouge, whereas in the flowline motion the tool wants to be in contact with the part to cut the surface. That's just a guess though.

When I see little motions like that, usually disabling one of the gouge checks fixes it, you just have to manually gouge check which can be dangerous.

This worked for me. Thanks for the tip.