Can I create a profile cut (projected onto 3D component below) in multiple shallow cuts?

[309cnc]

Hi,

I have a 3d model made up of three components. A base, a head rest and a couple tabs:

I then created a profile tool path using a 1/2" end mill to cut around the headrest. I want the depth of cut to follow the base and tab below and therefore selected the 'Project the toolpath onto the 3D model' option.

So far so good. The preview does exactly what I expect (I have also previewed the 3D finish tool path in the screen shot so you can see the profile cut better):

And, finally my question: Can I, and if so how, create this tool path to cut in multiple shallow (around 1/4" deep) paths instead of the single full depth path which would attempt to cut up to 1-1/2in deep in certain areas? I can't seem to figure it out.


Thanks for any suggestions


PS: A couple things I have tried unsuccessfully are a) I have tried limiting the path depth (0.1in in the example below) in the 'Edit Tool' window but it does not work. It still shows a single path once I close the tool edit window:

and b) I have also tried the 'Edit Passes' window but no luck changing anything there:

[Adrian]

You have no cut depth specified on your profile toolpath. Set a cut depth and then you can control the number of passes to reach that depth by either the pass depth in the tool database or the passes option in the toolpath itself. If you have it set to 0 it behaves like a finish pass and cuts the total depth in one go.

[309cnc]

I am not sure what to set the cut depth to as the top of my 'base' component varies in z-height. So I randomly set the cutting depth to 2in and left the 'Project Toolpath onto 3D Model' checked. The pass depth in the 'Edit Tool' menu is set to 0.1in.

Here is the preview:

So it is taking the expected 20 passes at 0.1in each but it ignores the 'Project onto 3D model' setting and cuts all the way through.....

??

[Adrian]

That's your choices I'm afraid. Single pass to follow the contour or multiple passes to a fixed depth. As far as I know there is no way to cut to a variable depth and have multiple passes.

Hopefully someone who does more 3D than me knows a way...

[adze_cnc]

So it is taking the expected 20 passes at 0.1in each but it ignores the 'Project onto 3D model' setting and cuts all the way through.....

It's not actually ignoring the 'Project onto 3D model' (PO3M). The PO3M option says that the top of the cut will follow the contour of the 3D model. In this case it is doing that and then cutting out everything below that model for 2 inches.

What you are looking for is an option for the PO3M to end the cut on the 3D model. That doesn't exist.

Your original post with a start depth of 0 and cut depth of 0 (I'd probably use 0.001 just to give Aspire something to believe that it's cutting to a avoid a divide by 0 problem) is pretty much the only option to simulate that behaviour.

If you worry about the bit potentially cutting through up to two inches of material in one go then add a boundary offset to your 3D Roughing toolpath to eliminate that material.

EDIT: I recently did a double-sided bowl-like model that had a curved and not flat edge. I modelled in a thin plane (0.004 inches) in the original Rhinoceros model that followed the contour of the real edge. I used the project to 3D model option with start depth 0 to follow my modelled plane and used a 0.004 inch depth of cut to force an overcut of that 3D model down to the real edge that I needed.

[309cnc]

What you are looking for is an option for the PO3M to end the cut on the 3D model. That doesn't exist

Thank you @adze_cnc! That explains why I am not finding it

If you worry about the bit potentially cutting through up to two inches of material in one go then add a boundary offset to your 3D Roughing toolpath to eliminate that material.

That's exactly my concern.

Your boundary offset suggestion is appreciated and it looks great in the preview. The red arrows shows area cleared out by the roughing pass and the green arrows point to the profile cut which now only has to cut through a small amount of material. Thank you!