What type of vacuum system do the "other" CNC routers use?
I am in serious need of a vacuum system. I'm working on signage and need to be able to pull the pieces flat against the table. I've been using strategically placed screw holes, but in some cases, it just isn't enough.
I'm comfortable designing the system, I just need to find the right vacuum pump.
Aaron Savka
If you have a lot of surface area, don't overlook the shopvac at least to get your feet wet(or dry)- Sorry
I was experimenting with a new fixture that leaked and my ventury and gast pumps couldn't keep up. Just to see what would happen, I held a shop vac hose up the the 1/4" inlet and was surprised at how much suction it had.
Sheldon, maybe you could confirm a point for us:
A ShopVac will give a reasonable hold down for large areas, PROVIDED THAT you do not expect it to do dust/chip extraction at the same time. If you want hold down and dust extraction simultaneously, you need TWO SEPARATE ShopVacs.
I have often been asked why it doesn’t work when you T the vacuum table line into the moving hose going to the router head – the leaks around the cutter are just too big and the ShopVac runs high flow, low pressure (way to the right side of the curve above)
Aaron,
My Morbidelli uses center valve actuated vacuum cups 125mm in diameter. The cups sit between parallel support bars. The material is pulled down onto the bars when cups are activated. This keeps it flat. Originally the vacuum source was a Piab venturi pump with a surge tank. It worked well but consumed a fair amount of air. I replaced the Piab with a Busch 5hp rotary pump. This works much better, you cannot move a 600 x 768 panel with 4 cups actuated.
Piab has a large selection of vacuum cups, fittings and venturi type pumps. Busch and Becker are both sources of rotary vacuum pumps. I think all three have web sites.
John Jorgensen
Aaron,
My Morbidelli uses center valve actuated vacuum cups 125mm in diameter. The cups sit between parallel support bars. The material is pulled down onto the bars when cups are activated. This keeps it flat. Originally the vacuum source was a Piab venturi pump with a surge tank. It worked well but consumed a fair amount of air. I replaced the Piab with a Busch 5hp rotary pump. This works much better, you cannot move a 600 x 768 panel with 4 cups actuated.
Piab has a large selection of vacuum cups, fittings and venturi type pumps. Busch and Becker are both sources of rotary vacuum pumps. I think all three have web sites.
John Jorgensen
Hi John, what is the thinnest (most flexible) material that you pull down onto the support bars which are presumably on 6" (150mm) centres?
What do you do when you want to cut right through the material?
Thanks for the info on the following:
Busch
Becker
Piab
(just click on the blue words for the websites)
Super Moderator
Gerald,
You're absolutely right about not being able to do vacuum and dust collection with the same ShopVac; too much vacuum is lost to the dust collector. I ended up removing the filter element from my vacuum-table ShopVac, figuring it was just a restriction for a vacuum application. At $100 or so for a ShopVac they're cheap enough to buy a couple. If they just weren't so darn LOUD...!
To make them last longer you'll do need to blead a little air into system to cool the motor on the ShopVac. I've heard that the Fien shopvacs have a seperate cooling fan so you don't have to bleed air. They also pull more vacuum and are quieter; anyone using one?
Bill
Hi Bill
A link to Fein - looks like the bigger model has the cooling feature.
(PS, Dudley's first sheets are arriving tomorrow)
Gerald,the holding cups and support rails are adjustable in approx .7 x 2.75M plane. 8 rail sets with 2 cups per rail. I can have anywhere from 4 to 16 support rails depending upon the panel size. With this support, deflection is not an issue. The smallest size I can cut is approx 300 x 400 x 3. Thru cuts are not a problem since the top of the rails are consumable MDF. Thru cuts are only .1 to .5 mm beyond the bottom of the panel, outside of the cup area.
If you built a channel for your ring system to ride in you would have a similar system. The height of the rails is approx. 1mm less than the relaxed cup/ring height. When activated the part is pulled down tight to the support rails while maintaining a tight seal. You could even add an outer ring to your system.
For a quantity of very small parts I'll build an intermediate table with cutting platform. A 1.5 hp lab vacuum is the source for this. Not much volume, great suction. Onsrud Cutter catalog (or machining guide for plastic) has directions how to build this cutting platform. The smaller the part the more critical feed speed and cut direction.
John J.
Gerald, Yes a separate dust collection and vacuum system would be needed. Can a Shopvac even keep up with the chips produced?
Bill, in Canada at least, Shopvacs are available in a QSP version which is much quieter.
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