Modular [grid] Vacuum fixtures..

[MetalFlake]

Has anyone here had to make a vacuum fixture that will accomidate a bunch of different parts? I need to pretty much do just that. The parts are mostly flat with some raised pads (.03-.08) and different outside profile shapes that are around 30" x 30". I think my boss is leaning toward a big grid pattern of grooves and just thread the gasket where ever I need them.

 

I haven't done a lot of vac fixtures. Any chance someone could get me a pic or good description of their vac fixture adventures?

 

Many thanks!!

 

MF

[crazy^millman]

Well a quick way might be looking at plastic for the top plate so you can easily machine the feature into it and not keep cutting into the top of a alumunim fixture. Then you could use the block as blockoffs for the places you do not want the vacuum to pull through. I am thinking a borrom plate with either alot of holes or pocekts and might think about being able to section it also. I have made some vacuum fixture using the insdie shape of a part and not have to use an oring but has to be a good fit and not much variance in the parts for it to work well. If flat stock keep in mind not crazy feeds and speeds or across the shop it will go.

 

HTH

[mold100]

Do a search I was looking into this not to long ago got some good ideas, everything but a vacuum pump, thats what I need now.

[Surface]

I'm working on the same idea. I have parts with different outside shapes which I was hoping to hold with a vacuum. Although smaller parts have a tendency to slide, and therefore enjoy being held inside a pocket, I think these are all large enough (8x30) that they can be just "sucked down" without fear of moving.

I am currently leaning towards the grid idea and using 1/8 tubing to contain the vacuum where needed. I hope creating a 1/2 inch square grid, will allow adequate surface area to hold the parts down sufficiently.

I’m curious what other members have to say.

[MetalFlake]

Surface...

 

I got a line on some rubber gasket that's supposed to be great for vac fixtures. It's about .187 square with a thin angled flap on one side.....reminds me of a windshield wiper blade. Ill try to get a part number for you.

 

email me...I'd like hear how your fixture turns out: [email protected]

[STKSHFTR]

Metalflake,

 

Take a look at magnalock.com. With some ingenuity you could pick up on stuff illustrated there.

We in the wood industry tend to cheap things out; I've used 1/4" Ø vinyl foam cord from MSC in a slightly tighter groove in a panel of sealed medium density fiber board capped with a piece of sticky back abrasive here and there for traction - worked great!

Agin, max out your square inches within the vac area, watch for leaks and keep your feed speeds down.

 

Marv

ICON Design LLC

MC Router Pro 9.1 SP2

[Mark Lovelace]

The foam channel seal from MagnaLock is what I have used. As Marv said, wood workers tend to go for the cheap solution. I have also used MDF on some pretty complex 'multi part' jigs.

 

What I would suggest is to figure out, as best you can, what pieces will share this jig. Then overlay them, aligned to any neccessary fixed location points, and find the common areas that you can seal off. Make sure that you have a vacuum port for each zone. I would only do your grid in the areas that you need. This is particularly important if you use MDF, as the core is somewhat porous, so anywhere you cut through the top you start to lose some vacuum. For this reason, only make your grid where you need it.

 

If you have some vacuum zones that you need for some pieces, but not others, then what I do is put a threaded insert into the back of the jig where the vacuum port is, then countersink a hole around the port from the top. You can then close off that zone, when needed, with an allen-head cap screw with an o-ring around it. You can make some pretty flexible jigs with this method.

[MetalMarvels]

I have been using the 1/8" EPDM Sponge Rubber Cord (P/N 31944622 from MSC). It even works nicely to "stop up" holes in the pieces so that you can maintain vacuum. It also works nicely in a "grid" arrangement - I have been getting very little "leakage" and the hold has been good.

 

I was getting very marginal success with silicone tubing - it just wasn't soft enough.