Hey guys, I am working on the design for a vacuum fixture for holding .0625 canvas reinforced phenolic that I cut a couple of different parts out of. Just straight profiling, I currently cut these parts by drilling the .125 mounting holes in one step in stacks of 16, then using those holes to bolt down stacks of 8 for cutting them out. This works OK, but I can't get the edge finish I need without sanding. Even with a compression router about half of them need a small amount of hand sanding to clean up the tearout. I have found that cutting one sheet at a time I can get the finish I need and since I can cut faster it will at worst break even on time required.
I am planning on making the fixtures out of HDPE and using .250 EPDM foam cord as a gastketing material. I have a preliminary design, was just looking for some critiques. Especially the ratio to vacuum cavities, to friction area, since this plastic is known to be fairly slick.
The attatched file is my preliminary design, the outer rectangle is ~6.5 x 8 in and is the outer profile of the piece. The 7 small holes are the mounting screw holes which will be drilled before this in a seperate operation. The next two rectangles inside that are the groove for the sealing cord. The furthest inside rectangle is the outer edge of the vacuum "basin" and the 1" circles are for support/friction area. This gives me ~17 sq in of vacuum area and ~33 of friction area. MY pump is good for ~22" mercury, about 11 psi.
opinions on vacuum fixture design
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