Thread: Vacuum and Clamping

Hi Daniel,
While vacuum clamping is a very good means of workholding it does not answer all your needs. I do a lot of through cuts and you would break the vacuum and damage your vacuum table under these circumstances. There might be techniques that overcomes this but I don't know of any.
I got a vaccum pump off ebay ready to make a vacuum table but it is yet to be made.
If you are interested in researching vacuum systems then this is a very good link to start.
http://www.joewoodworker.com/

Hey Rod,

Thanks for the reply. i agree with you that there is no one single hold-down technique that will work. The idea that for engraving i wouldn't need to clamp much does make it feasible. Also doing depron foam, you have to stand over the cnc and make sure the foam doesn't lift on the router bit, so something that could hold it down uniformly would be good. A standard vacuum would work but it would be better off to build a proper one that wont break down and something that could double up for other work too. A pressure foot doesn't work well with depron as it catches very easily and drags the foam around.

Its been a while since i was last on that site so i will have to sit down and read it one night.

Daniel

I am going to make a vacuum holddown ... well probably 2 at least. One for my Widgitmaster and probably 2 for my Alpha Zoot machine.
I have purchased one of the refrigerant vacuum pumps from ebay and am in the process of buying suitable connections etc. Some time ago I bought an air 'on-off' switch which looks like it will work well with the vacuum system.

On my Alpha Zoot machine, I have planned for a master switch for the vacuum pump, but am wondering if it is going a bit over the top to have a vacuum gauge in the control panel as well!! I have always liked dials and things, so the idea appealed, but is it practical or useful???

I checked out the joewoodworker site and he certainly has lots of good gear. Dissapointing about the exchange rate at the moment!

Cheers,

Alan

Hi Allan,
I know what you are saying about dials and things. I fitted things like tachos, vacuum and oil pressure gauges, analogue clocks and spotlight switches with little lamps to my cars before they become standard equipment. They didn't do much either but it made you feel good. The poms knew how to make a dashboard in those days with real wood and Smiths or Jaeger gauges.

Very interested to see your vaccum table advance so keep us posted. You are allowed to finish your machine first.

I agree, vacuum clamping is really only good if you are engraving etc, the moment you pierce through the material you have no clamping action at all. So far I found that my system works well for me, I have a 10mm steel base with 1/4 threaded holes every 100mm, this allows me to screw down, clamp down or use sliding jigs etc, basically an infinite number of clamping possibilities.

So far I have had no problems clamping any job that I have come across

What I have found from experience is that once you have the ability to hold things with vacuum you find all sorts of ways to use it that at first are not obvious.

I use it when cutting through material quite often.

Areas that are not to be cut through can be sectioned off with gasket material.

I often do what is referred to as onion skinning. A very thin amount of material is left. Much the same as tabs in effect.

Also I machine and drill PCBs with vacuum. The holes are so small that they do not overcome the vacuum.

Recently I have been cutting vinyl signs. Vacuum works great for this. Suck through an MDF board.

Occasionally I have stuck with spray adhesive thin material to a sacrificial board and held the lot with vacuum.

My point is that people who have not had vacuum at their disposal often do not realise just how useful it can be.

If my vacuum pump died I would buy another immediately. I would not choose to do without it.

Greg

Originally Posted by Greolt

What I have found from experience is that once you have the ability to hold things with vacuum you find all sorts of ways to use it that at first are not obvious.

I use it when cutting through material quite often.

Areas that are not to be cut through can be sectioned off with gasket material.

I often do what is referred to as onion skinning. A very thin amount of material is left. Much the same as tabs in effect.

Also I machine and drill PCBs with vacuum. The holes are so small that they do not overcome the vacuum.

Recently I have been cutting vinyl signs. Vacuum works great for this. Suck through an MDF board.

Occasionally I have stuck with spray adhesive thin material to a sacrificial board and held the lot with vacuum.

My point is that people who have not had vacuum at their disposal often do not realise just how useful it can be.

If my vacuum pump died I would buy another immediately. I would not choose to do without it.

Greg

Greg I am sure you have the info somewhere (links if possible) but what vacuum pump did you end up buying? I remember you converting a GMC air compressor are you still using that or are you using a Vac pump if so do you need a resevoir with that, I am sure you want to share before you head to the CNC workshop for the weekend

What CNC weekend? What am I missing?

I have the GMC which works quite well but is noisy.

That is the reason I got a refrigeration mechanic style pump. Less noise.

Look up this ebay number, 300297867462

They come in a few different sizes. Mine is 1/2hp I think.

So far I have not bothered with a reservoir. For what I use it for it is not necessary.

With the GMC it was good because it would cycle on and off, so less time hearing it's racket.

Greg

Just a cheap idea for you to think about.

I am vacuum bagging composites for r/c sailplanes. What I have set up is a "recycled" fridge compressor pulling down through a reservoir made from 100mm PVC pipe and all controlled by a $40 industrial vacuum switch (and relay) bought from ebay. This works very well and is good for 28" of Hg (22" here because I'm 5000 feet above sea level).

Much cheaper than a Gast vacuum pump or a vacuum transducer and compressor.

Kind regards

Dan

Hi Dan
Can you arrange a photo of your setup. Sounds really interesting.

Hi Rod

I will do my best to get a photo of it for you tomorrow - I'm in the process of cleaning up my building room at the moment and building a new work bench....

Dan

Our router came with a 7 HP 3phase vaccuum pump & blower, and a big vac bed.
I took it all off, poartly because I don't have 3 phase power & the noise it'd make if we did would be severe. I got a rotary phase converter to run the router spindle on single phase.
By removing the vac bed, we have much more clearance under the router head, too.

We have a big 30mm thick MDF bed, and I just tek-screw stuff into that to hold it down.
There are other workarounds you come up with. Yes I would probably like the vacuum if I had it, but I also manage efficiently like this.

HTH!

I thought this would be an appropriate forum to seek some advice on where to source pneumatic clamps and stops.

I have a BLUM Metafix clamping table that I am modifying to make it more versatile as a hold down and clamping unit. This unit was originally designed to clamp metal drawers for assembly and adding fixtures. Can't source the original retractable pneumatic stops anymore, so the options are to have some made or utilise off the shelf products and adapt them.

The key factors are that they be small units and be adaptable for t-slot fixing to the existing frames.

I have a small vacuum table that will be adapted into the existing clamping frame. The idea being to make it versatile as horizontal clamping unit as well as hold down clamp support materails whilst they are being worked on.

I am after sources for the supply of small pneumatic clamps and compessed air connectors etc. I have done a googgle search and that brings up loads of manufacutrers, but the specifics of products are a little light on. So I am after a recommendation of where to go to source these products.

Can anyone help?

PEN

A question to anyone who knows. On the weekend i was in the local auto shop getting a replacement window washer motor for SWCTM, and i ended up coming across the small compressors for car tyres. I had a look specifically at one for 4wd tyres. It was ~97 lpm and was able to obtain abot 120psi i think. The thing i noticed though was that it had a threaded port which was the inlet for the plastic filter but would be easily adapted for a threaded barb for the vacuum hose. Now my question would be, if i ran this through two chambers would it have enough vacuum or replenish enough to be used for a small vacuum table/pod system? I was also looking at the lower model which was ~40 lpm to use for a small vac table for depron foam which had the same setup.

Daniel