Rhino PartWorks 3D Female Mould Problem

[Charlie Iliff]

I am trying to learn how to cut female moulds for fiberglass layup of foil shapes. I can model the foil in Rhino, subtract it from a block and get what looks right in Rhino and after export in PartWorks 3D - a block with a foil-shaped pocket.
My problem is that when PartWorks 3D generates the cut files, even where set to cut top only and the model set zero below the top, the finish cut file tries to dress the outer perimeter of the block, rather than just the mould pocket. (It's found a couple of screws, so far - two expensive bits gone :eek:)
Is there a way I'm missing to instruct it just to cut the pocket?

Charlie Iliff

[steve_g]

http://www.talkshopbot.com/forum/showthread.php?t=11780

I think this thread answers your question

Steve

[Charlie Iliff]

Thanks Steve, but that thread sort of overlaps my problem and doesn't solve it. Putting negative numbers in for machining margins, where the program will accept them, does not stop the program from cutting the outline except in the part of the arbitrary rectangle that has been eliminated by the negative numbers. If you go far enough negative, it doesn't cut the model. I can't find a command to limit the cutting to the inside of the 3D model.
I suspect that I can make the 3D model a block with the pocket in it, it may do the cut I want, but then it will cut around the bigger rectangle. What I'd like to learn to do is direct the machine just to do the pocket which will be the mould - no border cut.

Charlie

[garyc]

Charles...
Try posting your questions in the Cut 3D section of the Vectric Forum: http://www.vectric.com/forum/

PartWorks 3D is Cut 3D rebranded for ShopBot only use. Other than output for non ShopBot machines, the 2 programs are identical.

[knight_toolworks]

try deleting everything that does not need cutting.

[Greybarn]

When we do this type of machine, we also machine the centerline flange divide for the mold. Don't you want to include that as part of the machining? How else will you get the flange for the mold?
Regards
Peter

[Charlie Iliff]

Charles...
Try posting your questions in the Cut 3D section of the Vectric Forum: http://www.vectric.com/forum/

PartWorks 3D is Cut 3D rebranded for ShopBot only use. Other than output for non ShopBot machines, the 2 programs are identical.

Already did that. Thanks

Charlie

[Charlie Iliff]

try deleting everything that does not need cutting.

I've done that, and the border cut is right against the sides of the pocket.:(

Charlie

[Charlie Iliff]

When we do this type of machine, we also machine the centerline flange divide for the mold. Don't you want to include that as part of the machining? How else will you get the flange for the mold?
Regards
Peter

That's probably the answer for ones with a center flange, but I had hoped just to use the original flat surface. I also hoped to use the same process to pocket for inset of shafts, etc.

[ron_churches]

I had a similar problem on a project awhile back. If I remember correctly, I was able to edit the mesh in Rhino and trim the surface that corresponds with the top horizontal surface of your material block, leaving only the negative space that composes the interior of the mold. If you want, send your Rhino file to me at gibraltarac@gmail.com and ill have a look.

Ron

[Charlie Iliff]

I had a similar problem on a project awhile back. If I remember correctly, I was able to edit the mesh in Rhino and trim the surface that corresponds with the top horizontal surface of your material block, leaving only the negative space that composes the interior of the mold. If you want, send your Rhino file to me at gibraltarac@gmail.com and ill have a look.

Ron

E-mail on the way, thanks.

[Charlie Iliff]

Ron Churches took the time to work with my file until he found a way. Setting the machine margin at .0001 (or other value a lot smaller than the bit, causes PW3 to ignore the margin cut and surfacing. It cuts only the pocket which will be the mould.
Thanks again, Ron

[Charlie Iliff]

Ron fixed one of my issues, but another has arisen. The edges of the female mould have tool marks rather than a clean and fair edge. I've tried bit sizes form 1/8 to 1/2, and raster X, raster Y and 45 degree, but although patterns are different, the edges are not smooth. Attached is a screenshot of the preview in PW3D. Test cuts confirm that the preview is accurate. I'd appreciate any suggestions.

Charlie