Vacuum Table

P

Pancerny

Mike Pancerny
Silver Member
Anyone had any success using a vacuum table for workholding in their cnc mill? I've been looking into these and wondered if those small vacuum pumps generate enough suck power to stop the workpiece from sliding when the endmill is cutting.

Thanks for any help!!
Mike
 
I don't think they are that great,
I use one in my shop for holding thin pieces
of graphite when i am surface grinding it,
If the pump and shit wasn't so heavy to ship
I would let you try it out
 
I have one that seems to work pretty good. The sucret is in the spongieness of the seal. Also sometimes it is good to have another tank as to add volume to the suction.
 
Pancerny said:
Anyone had any success using a vacuum table for workholding in their cnc mill? I've been looking into these and wondered if those small vacuum pumps generate enough suck power to stop the workpiece from sliding when the endmill is cutting.

Thanks for any help!!
Mike
Click to expand...

I don't use a vacuum table for inlays although I have one that I use for mitering veneers. I cut completely through my inlay material when cutting out inlays so there would be a loss of vacuum and the inlay could move near the end of the cut. What I do is glue my inlay material down to sacrificial substrate with spray contact cement (3M 77). This is screwed down to my table. Very easy, quick and economical. I buy 4X8 sheets of 1/8" hardboard and cut into 3X12" pieces. This comes out to 128 pieces for around 5.50. I drill a 3/8 hole at both ends 11" apart and I have all of my normal inlay material glued down and ready to go when needed. To remove the inlay material from the hard board I run a little Wax Wash paint prep onto the hard board and this seeps under the inlay and dissolves the contact cement.

Dick
 
rhncue said:
I don't use a vacuum table for inlays although I have one that I use for mitering veneers. I cut completely through my inlay material when cutting out inlays so there would be a loss of vacuum and the inlay could move near the end of the cut. What I do is glue my inlay material down to sacrificial substrate with spray contact cement (3M 77). This is screwed down to my table. Very easy, quick and economical. I buy 4X8 sheets of 1/8" hardboard and cut into 3X12" pieces. This comes out to 128 pieces for around 5.50. I drill a 3/8 hole at both ends 11" apart and I have all of my normal inlay material glued down and ready to go when needed. To remove the inlay material from the hard board I run a little Wax Wash paint prep onto the hard board and this seeps under the inlay and dissolves the contact cement.

Dick
Click to expand...


Hi Dick,

I used to use a similar method except instead of using a spray contact cement, I used carpet tape, (the cloth style which is much stronger than the paper.) The problem was that the glue would get stuck to the endmill when cutting through which drove me crazy cleaning it all the time.

Do you ever have that same problem with the spray adhesive Dick?

I'm hoping someone will have a recommendation about the vacuum pumps.
I know some cuemakers use these vacuum tables for inlays but I don't know enough about the suction power needed to keep the materials from sliding. The foam material comment makes sense and some of the sites that sell the vacuum tables also sell a rubber sealer which probably acts the same way and also allows sealing the extra holes.

Anyone know how the cfm rating works and what would be best?

Thanks to all,
Mike
 
I use one and the trick is to coat porus woods with CA before placing it on the vac table. I kept having problems switching inlay materials and using the same program to cut parts. Some fit perfect and others were cut a few thou off. I put a dial indicator on a slab of maple and saw the whole piece was moving slightly when the cutter changed direction. I removed the piece and coated it with CA and retried it and got zero movement. I now coat everthing other than ebony, cocobolo and similar dense woods. I have also used a table with glues and tapes however, I don't like the idea of using any chemical to remove adheasives right before I apply glue to the inlay and install it. I try to do all my inlays in one sitting as I run very tight tolerances.
I believe my vac pump runs $230 or so. Call me in the evening sometime if you want the part number. Chris. 720 206 4034
 
the easy way take your inlay mat say .150 thick write your program to cut your inlays at .125 leaving .25 then take your work off the vaccume table turn it upside down send it threw drum sander a few times the inlays fall out know problem, on real small pieces use tape on the cut side before running threw the sander there is no easyer way on earth to do inlays its quick easy and neat and clean I will post some pictures if I have time if not after the derby we are coming out with a dvd on inlays its very extensive
and even covers some programing for bobcad and mach 3.
 
! dont have my cnc up and running yet, Close but not Complete, but I have looked at several tables and here are two I think have at lot of possibilities.

www.m-powertools.com/products/u-mach-kit/u-mach-kit.htm

www.vac-clamp.com/vc price.htm

they are of the UK but do show US suppliers.

You can find pumps on Ebay Gast Manufacturing is one good one but there are several to choose from. Thomas is the one I have. Just search for Vacuum pumps. You will want to find one that pulls around 3-5 cfm. There are good sources on net to build nice set up for these pumps.

Dan
 
The above post about cutting close and sanding thru base is the preferred method that I have found in my searches on the web.

Dan
 
we have given some thought to making some simple vaccume tables there really are no affordable ones out there i have found some larger ones in the thousands how would one sound that worked great with the pump and ready to go under 500.00 let me known what everyones thinking i have already located a pump ok
 
I'm in the process of acquiring a CNC setup and I have read much about it in the last couple of months. At www.cnczone.com there have been comments on commercial manufacturers of CNC machines with vacuum tables saying that the pumps are so strong that the filters run full even if a suction system is mounted over the end mill. This requires emptying the filter pretty often, but it should be mentioned that this was happening when large pieces was cut (hence a lot of dust produced).

I think my solution on this would be to use Briannas method or using VCarve Pro which adds simple tabs on the cutouts which could be designed after you're own wish. I'm not sure if this would eliminate any small flex in the materials where the cutouts problems mentioned would occur.

N
 
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Vacuum? not for me.

I wouldn't recommend using a vacuum table. Especially if your trying to hold tolerances to a few tenths or less. If you don't have a valve, or perfect seal, you must run the pump until your completely finished. If rubber is a part of the sealing method for the vacuum table, there can be a small amount of movement, since rubber has a little give. It can be done, but you'll need high end components to do it.
If you want to cut perfect parts, and want to guarantee no movement then it's worth the time to glue your material down to a substrate that you can clamp, or bolt like the method Dick described which is an awesome method. The more complex the parts are, or if your parts need some assembly to continue pocketing, then you'll be glad your material is glued down. While a vacuum table can be convenient, it's just like the rest of the work involved in cue building, if you want precision there is nothing that will substitute going through the extra steps, or precautions. Go the extra mile.

Dennis
 
brianna187 said:
....the easy way take your inlay mat say .150 thick write your program to cut your inlays at .125 leaving .25 then take your work off the vaccume table turn it upside down send it threw drum sander a few times the inlays fall out know problem....
Click to expand...


This is how we used to do it in the toolroom when working with steel. Cut the parts on the mill, leaving about .010in of support material on the bottom. Then place the parts on the surface grinder (which has a magnetic table vise) upside down until you grind through the support material, leaving the desired part.
 
i always clamp the parts down also(i forgot say that sorry) and have never had an issue with any moving by clamping also you get a super tight fit to the table as Dennis mentioned which is very important i just found it very time consuming and hard not to break tiny parts . the sanding method i mentioned is the easyest way to go while still getting perfect parts but i do agree clamping tight is the way to go even with the vaccume table
 
pumps

searingcue said:
I wouldn't recommend using a vacuum table. Especially if your trying to hold tolerances to a few tenths or less. If you don't have a valve, or perfect seal, you must run the pump until your completely finished. If rubber is a part of the sealing method for the vacuum table, there can be a small amount of movement, since rubber has a little give. It can be done, but you'll need high end components to do it.
If you want to cut perfect parts, and want to guarantee no movement then it's worth the time to glue your material down to a substrate that you can clamp, or bolt like the method Dick described which is an awesome method. The more complex the parts are, or if your parts need some assembly to continue pocketing, then you'll be glad your material is glued down. While a vacuum table can be convenient, it's just like the rest of the work involved in cue building, if you want precision there is nothing that will substitute going through the extra steps, or precautions. Go the extra mile.

Dennis
Click to expand...
Hi Dennis, You have been to my shop years back and you looked at what I have used for 30 plus years, for a vacuum table. I build my own vacuum tables, made of delrin or other plastics, and sometimes made of aluimiumn plate. I machine the tables with a 1/4 ball mill, and machine only, .188thds. deep. I also use a rubber round seal, [ end cut at a 45 degrees angle, and glued with super-glue], when the pump [ coupled to a negitive tank],draws down the material, [no matter what matterial], it bottoms out on the tables slab and no movement at all. My inlays are as tight if not tighter than most I've seen. I'm not saying my way is best, but it's not broke, so I aint fixin it.

Also If you machine your parts correctly they will fit even tighter. I machine my parts with a crawl cut, then a climb cut for the last pass, and on the last pass I machine at a slower feed rate, taking about a .005 thds cut, and make sure the radius on the mill is down ino the inlay,by about.010 thds. I do the pockets and parts the same way, and this allows on to make even tighter parts in the female pockets. By doing this with a radius on both male and female parts, they snap in, and hardly not glue line if any.
blud
 
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rhncue said:
I don't use a vacuum table for inlays although I have one that I use for mitering veneers. I cut completely through my inlay material when cutting out inlays so there would be a loss of vacuum and the inlay could move near the end of the cut. What I do is glue my inlay material down to sacrificial substrate with spray contact cement (3M 77). This is screwed down to my table. Very easy, quick and economical. I buy 4X8 sheets of 1/8" hardboard and cut into 3X12" pieces. This comes out to 128 pieces for around 5.50. I drill a 3/8 hole at both ends 11" apart and I have all of my normal inlay material glued down and ready to go when needed. To remove the inlay material from the hard board I run a little Wax Wash paint prep onto the hard board and this seeps under the inlay and dissolves the contact cement.

Dick
Click to expand...

I use a system similar to Dicks, but I only glue the very edges down. That way when you cut through, they just fall out...JER
 
I take 1/8" plexiglass with the brown paper backing and cut a full sheet up into 3" by 12" strips. I super glue my material to them. I clamp the plexiglass to my parts table, and then cut through the material and barely through the paper. I can then pop the inlays loose and sand the paper off the back and stick them in the pockets. I have never used the vacuum table, but know many that use them with no problem also.
 
I have used double stick tape and a sanding drum for many years.
Works better than anything else I have ever tried.

Willee
 
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