Workholding-Have a bunch of small parts-how to hold down using vacuum?

[Nick Sorenson]

I have a bunch of small parts (.625x2.75x.062 thick) that have holes in them and I need to hold them down. There is only about 1/16 of area that I can use for vacuum on each side of the holes. So o-ring or other type of channel gasketing is out of the question. So I need some way that I can vacuum hold these down to a fixture plate (Dedicated fixture) and am lost for ideas. Both cuts (the circles and the profile of the part) are cut on the outside of the shape. In other words there's a 1/16" tool path around each 0.195"d circle and there isn't much left to gasket.

I tried placing the part right on the chambered PVC dedicated fixture board (no gasket) and it won't even think about holding down (leaks right past the workpiece). So I need some sort of gasket sheet maybe or some other form of seal I can use.

Any help would be appreciated!

I have a 1HP vac pump that works good for dedicated part holding in the larger parts I've cut so far. This one has me baffled.

[Jerome Stanek]

Can you use carpet tape to hold the parts

[Graham Wintersgill]

Screw your material to a piece of MDF, cut out all the little holes then screw through the holes to hold the pieces inn place (maybe use washers) and then cut the profile?

Just a thought.

[Mark Giese]

Two thoughts; Double sided tape as suggested before. My preference is to use Intertape 591, and cut it in multiple depth passes to minimize vibration and movement.

or, sub it out and have them laser cut as long as you do not have to glue any parts.

The latter will leave you with polished edges

[Chuck Gallup]

I have a bunch of small parts (.625x2.75x.062 thick) that have holes in them and I need to hold them down.

You say you have a bunch?
Carrots?
Consider making a negative mold from bleeder board that can accept a sheet of onion skinned parts.
Onion skin machine all the parts, then flip them into a mold that has been located and finish up?

[Ross Moshinsky]

Sounds like a job for a laser (assuming the material is able to be cut by a laser).

Otherwise, I'd think a custom vacuum pod/cup would work. You could try putting a piece of masking material on the backside of the material to close up some of the holes and get better suction as well.

[AL Ursich]

I have a Vacuum Sled in the Works for my CarveWright Machine. I cut tags from sheet stock and use double sided tape for now.

I bought a few bags of the mushroom looking dowel wood plugs.
I drilled 3/8 holes in my base board in a 1 inch x 1 inch.
I sealed the Sides and added a vacuum Port for a Veneer Continuous duty vacuum pump.
I layout my artwork then in the Art place Drill holes to let the vacuum hold down the part.
I remove the Line Art and run the Drill hole on a sheet of Hardboard on top of the mushrooms.
I now have a dedicated vacuum jig.
I remove the hardboard from the Mushroom Board and install another blank one for the next project.
If I drill a Mushroom, it pops out and I replace it....

Just and idea.....

And on my CarveWright, I hook a Vacuum Switch to open the cover switch circuit to stop the machine if I loose Vacuum...

It is still in the works....

AL

[Ralph Y Thorne]

Nick,

Allstar Adhesives has a couple of sheet foam products that work great. They are a family business, very helpful and don't mind small orders. If you need any more info, just let me know.

Ralph

[Mike Kelly]

Nick, you might want to look at a pressure foot hold down from Wigetworks. They make a couple for different ShopBots and one that you can adapt to whatever machine you may have.

http://www.widgetworksunlimited.com/...ure-sb_prs.htm

You can see some of the small parts in this picture that are possible with this real simple attachment.

[Jerome Stanek]

Plus 1 on the pressure foot