Bit rises after each pass VCPro 10.514

[nmflyr]

I cut out a part using profile toolpath. The bit retracted above the material after each pass. The path had 8 passes to cut out the part, and the bit retracted each time it made a lap, then plunged to the next pass depth. I can't find anywhere in the toolpath setup that can control this. Any help? This really added a lot of machining time to the process, especially since there were 8 pieces to cut out. Thanks.

[FixitMike]

If it is a slow plunge rate that is taking too much time, you can reduce the time spent plunging by setting a not very large value for Z2. in the Material Setup in the toolpaths window.

[sharkcutup]

I use the spiral ramp option when cutting out parts. It is a continuous plunge cut throughout.

You could try that to see if it is to your desired toolpath condition.

Sharkcutup

[Charlie_l]

We’re you using leads options?

[FixitMike]

Any time there is Z movement along with X, Y, movement, the bit will move at whichever is the slowest of the pass or plunge speed. If your plunge rate is quite slow, so will be the pass speed when the bit ramps. You can speed it up by increasing the plunge rate of the tool in the tool description.

If that doesn't help, then post the file here and maybe someone else can figure out what is happening. I tried to duplicate the problem and could not (VCarve Pro 10.514).

[nmflyr]

Did not have leads turned on. Will try ramps. I am trying to eliminate the bit retracting then plunging back. This is wasted motion and time. The X & Y are not moving during this motion. It is like drill pecking, but it is on a profile cut. Is there a setting that commands the bit to retract each pass? Thanks

[adze_cnc]

Before you start fiddling around with ramps and other complications we should try to figure out why a "plain vanilla" profile cut does this for you.

• what post-processor are you saving the toolpath with
• can you post a CRV file that exhibits this behaviour? You could make a copy of the original file and strip out all but the offending toolpath.
• can you post the file (g-code, tap, mmg, etc.) that you send to your machine that exhibits this behaviour?

[Adrian]

Are you machining an open vector? If so the profile toolpath will retract and return to the start point of the vector for each pass to respect the cut direction. With a closed vector it won't retract.

[Adrian]

Forgot to mention that if you are machining an open vector the retract will only behave like that if you are using the Left/Right option. If you are cutting On the vector then it won't retract between passes. That is assuming you're using 10.5 as before that all three options would retract on each pass.

[nmflyr]

Thanks for your ideas. There are no open vectors. I tried ungrouping all and regrouping, recalculaterd toolpaths and saved new g code. I re ran the project, and I was wrong on first description. The profile pass only lifted up before final pass. However, the bit did lift up above material after each pocket pass. Any help or ideas are appreciated.

[Adrian]

You said profile toolpath up until now. Pocket toolpaths always work like that as the software doesn't know if there is material in the way of the move back to the start for the next pass. The only way to remove the retracts if you know it is safe to do so is to edit the g-code or use a profile toolpath with a spiral vector.

[adze_cnc]

And the profile toolpath would retract for the final pass if you are using the last pass allowance setting.

One thing about the pocket toolpath that would be good is if it compared the current pass's XY end point with the next pass's XY start point. If they are the same then then no retract is necessary.

[nmflyr]

So how can I "tell" it where the last pass ended for the next path to begin?
I don't understand why the software wouldn't know where the material is, since it just removed the material during the pass.

[martin54]

So how can I "tell" it where the last pass ended for the next path to begin?
I don't understand why the software wouldn't know where the material is, since it just removed the material during the pass.

Only way to do that would be to edit the gcode, if you can learn how to do that then there isn't much that will hold you back when it comes to running the machine..
As far as I know the software has no way of knowing what it has previously cut, there are software programs with much more advanced toolpath strategies if you want to spend that sort of money

[sharkcutup]

I cut out a part using profile toolpath. The bit retracted above the material after each pass. The path had 8 passes to cut out the part, and the bit retracted each time it made a lap, then plunged to the next pass depth. I can't find anywhere in the toolpath setup that can control this. Any help? This really added a lot of machining time to the process, especially since there were 8 pieces to cut out. Thanks.

Have you tried the Spiral Ramp noted above? I use it quite often and I have never seen the bit retract during the toolpath!!!

Or edit your G-code to remove bit retracts!!!

Sharkcutup