Vac-Clamp (REVIEW)

[ynneb]

Here is a review of a cheap but effective vacuum clamping system that would be effective in many CNC applications.

If you doubt its strength, just see the inserted photo.

After reading this review, I would be interested in your thoughts about this device.

Do you think it would be helpful to your applications?

Do you feel that it would be good value for the job it does ?

What design modifications do you think it should have ?

[Pythagoras]

Wow, that photo is amazing. How can such a small device like that, have so much vacuum strength.

[HomeCNC]

I would be interested in another test.

My surface of my router table is flat and all at the same height because I took a small cut on the table surface with it's own router.

Is the Vac-clamp parallel to the feet? What I mean is if you bolt the vac-clamp down to a flat level surface, and you clamp a board on top of it. Is the board parallel to the table surface? If not, how far out is it?

[Moondog]

Hey Ynneb... good to see you back...

That Vac Clamp looks amazing.....

What is the base made from... Is it durable?... meaning would it stand up to repeated use in a manufacturing environment.

For a larger router, would it be possible to use several of these to hold an 8*4 sheet.

I suppose the number of clamps used would depend on the size of the compressor.

With your compressor, how many do you think you could hook up.

Do you think if you used 6 or 8 of these and placed a sacrificial sheet it would provide sufficient hold down for a Ply or Melamine sheet?....

Do you know of any Australian suppliers.

Thanks

[CNCadmin]

Nice job with the review Benny! How much noise does the system make when running, I guess one could hook up a vacuum system instead?

[ynneb]

HomeCNC, You ask a good question. The pads lugs are perfectly aligned with the bottom of the pad itself. The pad seems to be uniform all around. If there was some variance then I guess you could turn the pad upside down on your router and mill a fraction of the bottom to make it perfect.
When the work piece is sucked down, the rubber allows the workpiece to come in contact with the hard plastic and islands. There is no warpage.

Moondog, It is made out of a very durable plastic. I doubt it would suffer from repaeted use. I guess the rubber may need replacing from time to time.
I would expect most domestic compressors to be able to drive 4-6 of these units quite easily.
You asked for Australian suppliers, the product is actually Australian made.(Hence my willingness to do the review) Go to www.vac-clamp.com to find their retailers. They also export them world wide.

CNCadmin (Paul), You asked about noise. It is surprisingly quite ( Not counting the compressor ) Lets put it this way, once you turned on your router, you wouldnt hear any air noise at all. I dont know why you would want to put a vacuum onto this device in the first place. It does a fabulous job on its own with the compressed air. I tested the slippage up to 100 kg and it only just started to move, I doubt there is any cheap vacuum systems that could do the same. I was tempted to do a pull off test, but was afraid the tabs might break off with the possible 200 kg force required.

One other thing I failed to mention in the review was the fact that the rubber seal can be re-routed to form a smaller square or shape. This makes it suitable for small projects too.

[garagefela]

Hey Moondog,
Have a look at www.vac-clamp.com and click on the distributors link.

Cheers M

[ger21]

Originally Posted by Pythagoras Wow, that photo is amazing. How can such a small device like that, have so much vacuum strength.

vacuum can be up to 14.7 psi, so a 6" x 6" square can have 500+ lbs of clamping force, in theory.

[Vac-Clamp]

We RATE Vac-Clamps at 80% of absolute vacuum. That means that they are rated to pull -12.7 psi. They actually produce between 86% to 88% of absolute with a supply pressure of 100 psi. Given the full face surface area of the clamp, this will yeild a theoretical holding force of 330 lbs. Dynamic loads will always derate that holding force, but not by a huge amount.

Being injection moulded the "flatness" is not perfect. To give a broad tolerance +\- 0.25mm (+\-0.01") The way to achieve excellent results is to bolt the clamp down and do a skim cut over the whole face of the clamp. The material is a filled nylon, so it will machine very well.

Base is a filled Nylon (not glass). Durability is the key to this product, we have spcifically made the item to last and to be abuse tolerant. You can make a cut into the face up to 6mm (0.25") deep and the clamp will still work as good as a new item. One of the first prototypes has been in use by a school at least twice a day for the last 3 years. It is still working without fault, and they have not had to replace the seal yet.
Part of the design rationale was to allow chaining of the product to just about any configuration, at any time. You can start with one or two and add to them at any stage if or when the need arises. We have a number of people whom use two or three clamps and supplement stability by using support blocks of the same height. The support blocks will improve quality of cut.
The single sided clamp (VC4) uses about 1CFM. More clamps means more air consumption.
We have a different way of dealing with the through cut issue. A tall seal allows a shim to be put in between the workpiece and the clamp. This raises the workpiece off the face of the clamp to allow the through cut. The seal can be placed anywhere that the seal channel will allow.
The Vac-Clamp website http://www.vac-clamp.com has a list of distributors.

We have not done a noise test on the product, so I cannot give a difinitive answer on this. An air dusting gun/blower is noisier.

Errol Weber
Vac-Clamp

[braidmeister]

The Vac-Clamp is a nice product for Milling machines and CNC routers where the substrate to be machined is non-porous. It's a well-made product with many uses.

Any hi-vacuum/low CFM setup, such as the Vac-Clamp, or systems that use HVAC style small rotary pumps will not be adequate when machining a porous substrate such as wood. In this case, I have found that a regular Shopvac, while putting out only 3" of Hg (mercury) and over 100 CFM, gives excellent results, in combination with a purpose-built plenum. The high CFM/Low Hg" is suitable for a router. My current Shopvac, a Fein Turbo III, puts out 7.3" Hg and 126 CFM...I thought it was going to suck the blood out of my hand the 1st time I used it!!!

It is probably the best bang for the buck as far as a vacuum source for CNC routing goes and it gives me twice the suction as my Ridgid. Gasketing is just as important as your vacuum source. I use AllStar spoilboard gasketing...and it makes all the difference in the world on small parts.

-Brady

[Scott_bob]

I wonder what the clamping force "drop" would be at 6,000 feet elevation, relative to sea level?

Anyone want to guess what the potential clamping force of a properly tightened SHCS, say: 1/4-20 UNC?

[Vac-Clamp]

We find that most of the places that Vac-Clamps are being used are with wood or wood products. The results are rather good.
The clamps do struggle a bit with low quality MDF and of course if the wood has a knot hole, but usually the clamps hold very well.
One of the vac-clamp users works 2 VC4 clamps on his CNC router. He cuts out bed components from veneered MDF. We also have more than a few working pinus radiata with excellent results on the clamps. 2 clamps works very well with support blocks on very large pieces. We will post some pictures on the website to show this
The face seal can be sized to hold small pieces (minimum size 50mm x 100mm, 2" x 4"), and the double sided can be put anywhere on a table or bench.
No moving parts inside the unit to wear out or break down gives you the reliablility, and the seal is replaceable.

At 6,000 feet elevation the air pressure drop will give a reduced performance, but not as much as you might think. We did some calcualtions and found out that at the top of Mount Everest (29,000ft, 8,845metres) the performance would be halved, due to the reduced ambient air pressure.

We will be attending the AWFS fair in Las Vegas (27th til 30th July) and will be demonstrating the clamps there (booth 12362). Come along and have a look and see for yourself.

Errol