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CAM: Fixed Contour Area with Spiral drive method gives unwanted retracts
3

CAM: Fixed Contour Area with Spiral drive method gives unwanted retracts

CAM: Fixed Contour Area with Spiral drive method gives unwanted retracts

(OP)
Hi,

I'm having trouble getting a suitable milling path for milling a curved circular surface.
I have this ring with has a wave-like side with a curved surface which needs milling using a ball cutter.


I was planning on doing this with a Fixed Contour Area operation with a Spiral drive method.
The first paths I came up with were like in the picture below.



As you can see it lifts on the inside (collision check is on, but check geometry is far enough away), but I could live with that (it cuts from the inside to the outside).
I imagine this is because the ball cutter can't cut there yet (due to the wave-like surface).
However, on the outside it suddenly plunges down and goes back up for an unknown reason.
With other sizes (the ring has to be milled in a range of sizes) I've seen this plunge go deeper than the shank of the mill.
This plunge is one thing I need resolved.
Anyone got an idea why NX thinks this cut is necessary?

A second path I came up with improves on the lifting.
Instead I engage and retract with an arc normal to the tool axis and traverse directly (see image).
The previous path had the same settings with collision check active, this one has it disabled.
At first it looks like it goes fine. But on the outside, the plunge is a real problem.


After it plunges, it retracts towards the ring effectively cutting where it shouldn't, probably breaking the tool.
It should retract away from the ring, or better yet not plunge at all.
I don't really see why the collision check would cause the lift as I don't see anything that might indicate a collision.

Any help would be helpful.

Thanks in advance,
Jeroen Duré

RE: CAM: Fixed Contour Area with Spiral drive method gives unwanted retracts

2
Have you tried using streamline as a method?
Attached is an example I worked up in NX9. Images you supplied aren't 100% on the shape your machining, so I took a guess.


Anthony Galante
Senior Support Engineer



NX3 to NX10 with almost every MR (21versions)

RE: CAM: Fixed Contour Area with Spiral drive method gives unwanted retracts

(OP)
Thank you very much.

I hadn't tried streamline yet. I didn't realize it had the option for a spiral drive method.
Now I've tried it and it seem to work as I had originally planned.
Many thanks for your response smile.

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