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Solid Sweep Cut - grinding wheel along helical path fail

Question asked by Ken Ballinger on Mar 18, 2019
Latest reply on Mar 23, 2019 by Ken Ballinger

Hello SW Forum,

 

I'm working on modeling very tiny cutting tools. My end goal is to be able to show accurate part geometry of a < 0.060" diameter rod stock being fluted by roughly 2.5" diameter grinding wheels at 6-8 degree helix. I had thought the Solid Sweep tool would be perfect for this. But, sadly, it generates unacceptable geometry. I've run some tests (attached) to try to understand the SW tool's operation and it looks like A) horizontal axes of rotation (not intersecting the path) and B) increasing the grinding wheel's diameter makes things worse. Even a smaller wheel still creates unrealistic geometry. It fails in both SW 2018 2.0 and 2019 SP 1.0.

 

All cutter profiles are drawn on the same plane and in red (below).

Here you can see the first pass (red path) is a simple ball mill modeled on a vertical axis of rotation. Seems to work.

The second pass (orange path) is a tapered cutter which also has a vertical axis of rotation. I was testing the "all cutters must be convex" rule (i.e. is a straight line "convex" to SW?) Also seems to work. That's the end of the good news.

 

Solid Sweep Test Snip 1 031819 KB18.PNG

 

Here is some of the unacceptable geometry of the small wheel - horizontal axis of rotation.

Solid Sweep Test Snip 2 031819 KB18.PNG

 

The larger wheel on a straight path (not normal to the cutter's profile). Yikes!

Solid Sweep Test Snip 3 031819 KB18.PNG

 

Things get even worse when I go to the helical cutting path. The small wheel doesn't even cut through the starting face.

Solid Sweep Test Snip 4 031819 KB18.PNG

 

IF this tool worked it would be perfect for what I am trying to achieve. Any advice on how to A) get this tool to work as I think it should or B) model what I need? I'll let you know if my VAR has any tips.

 

Edit 3/18/19, 5:23 pm: My VAR pointed out that the second cylinder in my model was patterned with a cut already in it. That was a mistake caused (by me) by a last-minute restructuring of the Feature Tree to try to group operations. However, it should have had no bearing on the final shape of the second helical cut because the second helical cut would have removed everything the first cut would have removed and then some. In any case, I went back and tried it again without the patterned flute and it still made unusable geometry.

image (1).png

I also tried it again with the tool tip right at the path (purple) instead of having the tool path intersect just somewhere in the field of the tool profile. No luck.

Solid Sweep Test 2 Snip 5 031819 KB18.PNG

Still working with VAR to find a solution. More to come (hopefully).

 

Thanks All,

--Ken

Windows OS 10 Pro

Dell Precision 7720

Intel i7-7700HQ

SW 2018 SP 2.0

SW 2019 SP 1.0

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