Vacuum for small parts cut from thin laminates?

[scottcox]

Hey 'botters!

I'm looking for suggestions to hold down small parts cut from a full sheet of 1/16" plastic laminate. Good possibility I'll be cutting many of these same sheets.

I've been using screws, double-sided tape and luck so far to keep my parts from flying. I need to do better. I think this type of work may be a good candidate for a vacuum table, but I'm unsure of the method.

Assuming that I build a Bradyfied 9-15 vacuum setup, would it best be used with a fully porous spoilboard/grid or should I cut slots under each part so that they are open to the vacuum grid?

To clarify, I think that I should cut a full sheet grid into MDF, flip it and surface the top, seal the sides of the grid sheet and top of the existing table top. This will pull my vacuum through the top of the new sheet, correct?

Should I then cut through slots under all of my parts to expose them to the vacuum grid? Maybe exagerated recesses for the bit travel paths around each part? Then seal everything?

Corrections? Suggestions? New ideas?

Thanks for any feedback.

[scottcox]

I should have mentioned that leaving a skin on this stuff is not a great idea. It's very hard and time-consuming to remove the left-over edges.

[Brady Watson]

"Should I then cut through slots under all of my parts to expose them to the vacuum grid?"

Yes. Except offset your vectors 1/8 to 1/4" to the inside of your part and area clear them to create an individual plenum. Then do a machine along vector in the center of each part to puncture the grid underneath. This treats every area clear/pocket as it's own plenum.

This configuration is what I call the 'BradyVac II', and it is meant for production fixturing of parts like you describe. Use the regular 'BradyVac' for general cutting...this one if you want gobs of holding power for a specific job. Note: You charge the customer for vacuum jigs - PERIOD! Now you have no excuse not to use a dedicated fixture for a challenging job.

There will be a full write-up on this in a week or two. I have literally cut thousands of parts using this setup at over 6 IPS, during the past 3 weeks.

The example I am going to show you uses a single Fein T3 vacuum. The parts were held down so well & the vacuum so tight that you had to wait about 5 sec after the vac was off to remove the parts.


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Example of tightly nested parts on 4X8 sheet using just one Fein ShopVac. Scrap in between parts is only about 1/2" and stays put.


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Area Clear/Pockets that create plenum along with MAV channels that puncture the grid blow, feeding each integrated pod vacuum.


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Vacuum swarf out of channels and clean up fuzzies using the same MAV with a 90° vee.


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Channels cleaned up with 90° vee to improve flow and make it look all purdy.


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Anatomy of the BradyVac II Production Jig.

The nice thing about this setup is it uses no gasketing, and although I used Trupan, you can use ANYTHING to make a jig like this. Regular MDF, Plywood, PVC etc. The advantage of Trupan and low resin content MDF is that the areas outside of each individual part is held down too. So your scrap gets held down with whatever vacuum is left over from each integrated pod. What's nice is that you can use ANY vacuum power plant whether it is a Fein, 4 Feins, a big honkin' roots blower or regen. Just make sure that you don't attempt to use this over you existing bleeder. You'll want to have free-flowing vacuum air directly under the BradyVac grid.

The last pic shows chips/cutting debris after scrap & parts were removed. Rather than risk damaging your 'Trupan gasket', either blow off the chips or program the Bot to suck up the chips with the DC while you prepare for another sheet.

This is THE easiest, fastest, cheapest and most effective bang for your vacuum buck anywhere, straight out of the iBILD 'SkunkWerks'...Give it a whirl...you're gonna love it!

-B

EDIT: One side note on the area clear portion. If you are cutting thin or flexible material, be sure to add island stand offs in the middle of the area clear so that your material doesn't buckle and sag under the suction of the vacuum. This can throw off your final dimension. Just like using vac tape, ya gotta put some in the middle of the field to keep things flat.

[scottcox]

Excellent info as usual Brady!! Thanks!!!

I'm going to order the vacuum motors from Lighthouse and start on this. I've been looking forward to a vacuum system for some time. This will be a nice add-on to the 'bot.

[Brady Watson]

Scott,
Be sure to add a filter to the motors since the BradyVac II will allow chips to enter the grid & vacuum motor unless there is a filter to stop it.

-B

[scottcox]

Check! I do plan to build a filter box. I'm also considering mounting these outside the shop in a closet where my dust collector resides. Any comments on the noise levels of these pumps? Are they screamers?

[Brady Watson]

They are as loud as any other unmuffled ShopVac. If you get creative with the sound deadening, you can get them to be as quiet as a Fein. Some testing with egg crate foam like that used for bedding worked very well. Just take care how you use it as the vac motors do get hot.

Be careful about mounting them too far away from the bot. You will reduce CFM. Imagine if your air cleaner/air intake to your car was mounted in the trunk with the engine all the way in the front...same deal.

-B