Experimental vacuum plate

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TomB
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Post by TomB » Tue Apr 15, 2008 7:20 pm

I may be missing something, but I would consider doing away with the seals and just covering the whole table, except for a hole where the part fit using a piece of roofing tar paper. I figure I could aford a new piece of roofing paper for every size part I wanted to hold down.

Tom

Jose Rivera
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Vacuum plate

Post by Jose Rivera » Tue Apr 15, 2008 10:05 pm

Yeah, I'll do something soon and I'll consider you suggestion as well.

Meantime, I have been using it and works great, but it could be even better once I get some bugs out, like mounting the vacuum pump away from the machine table. Is transferring vibration to the mill.

Solving the sealing problem and moving that pump out of the way will solve most of my problems.
Another thing I would have to do is isolate the pump with a box with foam to dampen the noise, but I would have to add a fan to keep it cool.

I made a safety lock for my new Clausing mill switch I won on eBay using the vacuum plate and the CNC mill.

I got inspired by Fred Ford's home page where he show his version for his drum switch. http://www.frets.com/FRETSPages/Machining/index.html

Since I am more concerned about accidentally using reverse, I put a lock on the reverse direction only
Attachments
Test.JPG
Vacuum pump.JPG
DSCF4046.JPG
DSCF4045.JPG

Jose Rivera
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Another job with the vacuum plate

Post by Jose Rivera » Fri May 30, 2008 6:25 pm

I have been using the vacuum plate regularly and I still have to do some improvements.

The Vacuum pump get pretty warm, so I am going to build a shroud and have air being pushed by a fan thru the gap in that shroud.
Another unexpected job :?

I am cutting parts for my little Hummingbird Micro Drilling Table.
I have sold all five of six I made (one ended up for parts) and I am getting started building another ten.
http://www.youtube.com/results?search_q ... arch_type=

Little Machine Shop is going to carry them in their stock soon.

:lol:
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CNC.JPG
There are no problems, only solutions.
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Retired journeyman machinist and 3D CAD mechanical designer - hobbyist - grandpa

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DICKEYBIRD
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Location: Collierville, TN

Post by DICKEYBIRD » Sat May 31, 2008 8:47 am

In another life & hobby, I cut all my sheet balsa & ply parts for RC model airplanes on this homemade CNC router.

I made a simple worktable/plenum from plywood and masonite with 576 holes drilled in it. The 1st job for the machine was to drill those 576 holes. I clamped 4 pieces of 1/4" foam board on it to be drilled at the same time and used those for sacrificial backing under the work to keep from carving up the table.

I just used a standard shop vac for the vacuum source. It held all work tenaciously as long as I covered any unused holes with cardboard strips.

I have done zero, zilch, nada RC designing/building/CNC cutting since I got my lathe & mill but still use it occasionally for the odd engraving job.

Image

Image

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Milton in Tennessee

"Accuracy is the sum total of your compensating mistakes."

Jose Rivera
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CNC

Post by Jose Rivera » Sat May 31, 2008 2:05 pm

Did you make this CNC or you bought already made?
Nice little machine!

I bought mine from a friend that is nuts about making CNC mills.

I use plastic as substrate to cut thru also.
With the vacuum plate I am using crazy glue to hold the metal to a 1/4 Plexiglas as substrate. Then after finishing, I hit the parts with a small torch until they drop off like dead flies.

The method that you use is what they do with large wood routers, blocking the open holes with pieces of plastic or plywood.

I opted for a vacuum pump because I had one first, second vacuum cleaners are very noisy. Much more than the pump.
Also this pump has lots of sucking power, enough to machine metals.

I am new at this of sorts, specially on using a vacuum to hold parts.
I used to use double-sided tape. I still do on occasions.

As you, I go some times moths without touching the CNC mill and then I have to re-learn things, is tough. :cry:
There are no problems, only solutions.
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Retired journeyman machinist and 3D CAD mechanical designer - hobbyist - grandpa

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Mike_Henry
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Post by Mike_Henry » Sat May 31, 2008 3:30 pm

millman5 wrote:If the buna N doesn't compress enough to allow your part to pull down flat. I seem to remember seeing closed cell foam cord somewhere in one of my publications.

When I was in the automotive machine shop business, I had a vacuum crack detection bench that used a piece of closed cell foam to sit the head gasket surface of a cylinder head to. With 20 in. Hg pulled on that you couldn't have knocked one loose with a sledge hammer.
Gore makes an expanded-PTFE seal material that has a round cross-section like an O-ring and in diameters as small as 3/32". See McMaster-Carr, page 3401 for sizes and pricing.

We use some adhesive-backed closed cell foam material at work to create laminated gaskets. The CCF material is available in thicknesses of 1/32 and 1/16". I think that the 1/16" material will squeeze down to about 0.015" thick with enough pressure/force. I suppose that a flat sheet gasket would be more of a PITA to work with than an O-ring, though.
Last edited by Mike_Henry on Sat May 31, 2008 5:48 pm, edited 1 time in total.
Mike, near Chicago

Jose Rivera
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Seals

Post by Jose Rivera » Sat May 31, 2008 5:31 pm

Ideally the parts should seat all the way down flat with the tops of the plastic table.

The hardness of the O ring vs. amount of vacuum does not let this happen.
So I put a shim inside the vacuum area. I need to play more with the type of O ring.
I am sure that there is a grade soft enough for what I am using.

Right now I am up to my ears with projects. Not enough time for everything.

Thanks for your input. I will run a check on Mc-Master-Carr
There are no problems, only solutions.
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Retired journeyman machinist and 3D CAD mechanical designer - hobbyist - grandpa

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DICKEYBIRD
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Location: Collierville, TN

Post by DICKEYBIRD » Sat May 31, 2008 7:39 pm

Thanks Jose. I built the router back in 1998 out of MDO plywood from plans I saw in the Dec. '94 Nuts & Volts magazine. I modified it & strengthened it to suit me and used a MAXNC 3 axis stepper motor/controller kit. It is slow and weak but I learned a bunch about CAD & CNC with it. It's amazing how accurate it is with simple drawer slides for the rails!

Now if I could only afford to convert my X-3 to CNC! :D
Milton in Tennessee

"Accuracy is the sum total of your compensating mistakes."

KenHMT
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Re: Vacuum plate

Post by KenHMT » Mon Nov 19, 2012 10:41 am

Jose Rivera wrote:I made a safety lock for my new Clausing mill switch I won on eBay using the vacuum plate and the CNC mill.

I got inspired by Fred Ford's home page where he show his version for his drum switch. http://www.frets.com/FRETSPages/Machining/index.html

Since I am more concerned about accidentally using reverse, I put a lock on the reverse direction only
Really nice-looking setup!

Added to the database at homemadetools.net: http://www.homemadetools.net/rotary-switch-lockout

Ken

Jose Rivera
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Location: Vallejo California

Re: Experimental vacuum plate

Post by Jose Rivera » Mon Nov 19, 2012 10:21 pm

F.Y.I.

Just a matter of information about the vacuum plate.

It works, but I opted for either double-stick tape or regular hold-down clamps.

1) The reason is that the noise of the pump is annoying.
2) Extra electricity needed.
3) If the job needs to be continued later, turning the pump off will shift the location a little. I corrected this by using three dowels that will allow to re-locate accurately.
4) Larger parts will not hold enough because they require more vacuum than the pump provides.

For some special purposes yeah, is handy, but the experiment was just that ... an experiment.
There are no problems, only solutions.
--------------
Retired journeyman machinist and 3D CAD mechanical designer - hobbyist - grandpa

hammermill
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Re: Experimental vacuum plate

Post by hammermill » Tue Nov 20, 2012 12:19 am

put a small to mid sized spin on oil filter after the contamination filter noise will drop next to nothing

Harvey M Richards
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Joined: Mon Mar 14, 2011 8:36 am

Re: Experimental vacuum plate

Post by Harvey M Richards » Tue Nov 20, 2012 12:34 pm

Jose Rivera wrote:F.Y.I.

Just a matter of information about the vacuum plate.

It works, but I opted for either double-stick tape or regular hold-down clamps.

1) The reason is that the noise of the pump is annoying.
2) Extra electricity needed.
3) If the job needs to be continued later, turning the pump off will shift the location a little. I corrected this by using three dowels that will allow to re-locate accurately.
4) Larger parts will not hold enough because they require more vacuum than the pump provides.

For some special purposes yeah, is handy, but the experiment was just that ... an experiment.
We built a vacuum table at work to hold plastic parts. We have a compressor shed and we located the vacuum out there, so there is no noise inside. The vac also has a remote indoor switch along with a 5 gallon holding tank.

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