Why there are collisions?

[thburn]

Hi,

I tried to setup a toolpath but got some trouble with collisions.
I just wanted to make the tool follow a circle (I don't created any body).

For this toolpath I need a lead out which just leaves the circle tangentially for 10mm.

1st problem: I cannot set the 'Lead-Out sweep angle' less than 5 deg. But since I want to leave the circle tangentially I need 'Lead-Out sweep angle' to be 0 (zero)

2nd problem: I need a 'Linear Lead-Out distance' of 10mm or more. But I only can enter up to 4mm.

In both cases I get an error message saying:

Warning: A contour was not machined because the given lead parameters would cause a collision!

Warning: No passes to link.

Generation completed with 2 warning(s) in 203.4ms.

Warning: Empty toolpath.

Why I get this error message? I really wonder where there is a collision since I don't have any body to collide against.

It would be really great if we could SEE where the collision happens - otherwise we are left in the dark to find the reason.

In this screencast you can see what I tried:

And attached is the F3D-file.

Thanks for any help...

[ivan.stanojevic · Accepted solution]

If you extrude your sketch and select the same contour it will work.

After that you can hide the solid body.

I don't understand why do you want to do it without a solid body.

[thburn]

@ivan.stanojevic: thanks, I just need it for my drag knife. So I just need the path - Anyway I will try your proposal.

[daniel_lyall]

If you do a search of this part of the forum A person a few weeks ago said how he got it to work sort off

[Steinwerks]

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@daniel_lyall wrote:

If you do a search of this part of the forum A person a few weeks ago said how he got it to work sort off

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This one?

https://forums.autodesk.com/t5/computer-aided-machining-cam/leadin-for-circle-not-working/m-p/688217...

@thburn Why not continue the previous thread? I realized after I posted that that one was started by you as well and is addressing much of the same topics.

[Steinwerks]

Also you're cutting on the wrong side of the contour to allow for a simple straight line tangential lead out:

This happens when you're using a sketch because the CAM can't guess what you're trying to do, it's just a 2D line. Reverse that arrow (change the cutting side) by clicking it and you can set the angle to zero and have a 10mm linear lead out no problem:

Edit: think of it this way. At 4mm and a 5 degree sweep you clear the inside of the circle, which in this case is the cutting path also. Reduce the angle or extend the linear lead, and the entry runs over the toolpath itself. The CAM won't let you do that, so it fails instead, since that would be a collision. If you increase the sweep to 20° you can certainly use a 10mm linear lead out but since the cut side is on the inside of the cut geometry it will protrude inside the circle:

I hope this clears up why you were getting a toolpath failure.