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  • Vacuum Grinder Plate

    Recently on a trip to Georgia I picked up a Big Vacuum pump. Now am thinking of various Vacuum Plates for the Surface Grinder Milling Machine maybe the lathe?? I wonder if a Filter would be required to protect the pump from Small swarf ect? Also i am curious as to how exactly would be a good way to make a really Nice one.?? How about a air control or regulator > Is that requirerd also?

  • #2
    Originally posted by madman
    Recently on a trip to Georgia I picked up a Big Vacuum pump. Now am thinking of various Vacuum Plates for the Surface Grinder Milling Machine maybe the lathe?? I wonder if a Filter would be required to protect the pump from Small swarf ect? Also i am curious as to how exactly would be a good way to make a really Nice one.?? How about a air control or regulator > Is that requirerd also?
    Hi madman.

    I had occassion to check one of these out for myself.

    I think that this link will assist as it seems to answer all the questions.

    http://www.ibagnorthamerica.com/pdfs...PartsChuck.pdf

    I found it on Google search = vacuum plate

    I'd imagine that if you had a close look at them you'd be able to make one to suit.

    They are essentially a vacuum version of a magnetic chuck with the benefit that what ever you want to hold does not need to be ferrous or magnetic.

    The same caveats/warnings as apply to magnetic chucks apply to vacuum chucks. Insufficient or loss of vacuum would need to be avoided and small or thinner parts would need to be "backed up" as is the case
    on a magnetic chuck.

    You'd need to be very sure that no dust or swarf got into and blocked any of it. You'd need to be even more careful if you considered using cutting or coolant fluids.

    The specifications for the vacuum plates would probably specify the level of vacuum and cleanliness of the air supply required. I'd think it would be somewhere between very prudent and essential to have a very efficient filter on the line between the vacuum plate and pump - to protect the pump.

    If you don't have a vacuum receiver "tee-d" into the vacuum line I'd be very wary of the pump failing when your machine was under a cutting load as it might let go with a bang. The vacuum reciver might only need to be an old air receiver - not very big, just enough to keep the vacuum going until you can make your setup safe.

    Why not see a local Cabinet Maker or Joinery - or "Woodworkers Clubs" as they seem to have a real interest in and use for them.

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    • #3
      I've used them on VMC's. The one we used ran off shop air and would pull around 27.5"Hg, which is a pretty decent vacuum. The vacuum plate we used had a grid of 1" squares milled out with grooves that would accept a round foam rubber seal. It was around 3/16" or so in diameter, maybe a touch smaller.
      You would press the foam seal into the grooves so that the maximum amount of surface area was covered under the part. In each square was a drilled and tapped hole with a precision c'bore (just like a Carrlane tooling plate) that you could put edge stops in to mill and locate against.

      You need to know how much force the atmosphere is applying to the part. The greater the surface area the better vacuum plates work.

      For our purposes (yes Even, I know this is technically wrong, but it works well enough for us dubbers) we can assume 30"Hg or 0psia or -14.7psig is a perfect vacuum. So if your gage says you have drawn 27.5"Hg you have drawn 27.5/30=.91 of perfect vacuum. .91x14.7=13.46psi of atmospheric pressure acting as down force on the part. And because the grid pattern was in 1" squares its was just a matter of counting up how many squares were inside the foam rubber seal, multiply that count by 13.46 and you get how much down force is really on the part.

      We made some custom vacuum fixtures too where the seal was pressed into a groove that was generated on the VMC, we also had holes drilled through some of the parts so there were circular grooves around each hole with o-rings pressed in to maintain the vacuum when the drill went through the sealing surface of the part.

      Vacuum is fantastic for sheet metal work on a VMC, we did some prototype panel faces, because the thinckness of the material has zero bearing on how well it clamps down; unlike mag. chucks that rely on thicker material to transfer the magnetic flux from one pole to another.

      Cleanliness is paramount, if you leave a small chip under a thin part it will look like its drawn down but there is really a leak and if you don't check your gage before you cut you could be in for a suprise. My suprise only cost a 1/2" carbide endmill. I was lucky!
      Ignorance is curable through education.

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      • #4
        Originally posted by Rusty Marlin
        I've used them on VMC's.
        ..............

        Vacuum is fantastic for sheet metal work on a VMC, we did some prototype panel faces, because the thinckness of the material has zero bearing on how well it clamps down; unlike mag. chucks that rely on thicker material to transfer the magnetic flux from one pole to another.

        ...................
        Thanks Rusty Marlin.

        My interest was machining the edges of thin sheet - say 1/16" to 1/8" thick - not many - only a few.

        I don't fancy using my magenetic chuck as the edges of the magnets are too far (for my comfort anyway) from the edges of the chuck. The sheet edges also have to overhang the chuck - this is quite a lever arm in what is essentially a "vibration environment" if I use a normal right-handed helical end mill cutting on its side without using a "climb-milling" process. The sheet could "let go" at any time as soon as the slightest gap between the sheet and the mag chuck appears.

        I have considered using a fairly weak arched spring (as in an automobile suspension leaf-spring) in the "arc up" position and drawing it down with bolts to my mill table and have the cutter in one of the "T" slots or near the edge of a supporting "packer". Other options are to buy a left-handed spiral cutter or use (perhaps modified on my T&C grinder) a "timber" TC router bit as it has "straight" teeth. Any "mistake" or "disaster' would almost be guaranteed to take a bight out of my milling table.

        Hence my interest in the vacuum plates.

        I will be interested to see how this thread progresses.

        Comment


        • #5
          Vaccuum Plate

          I am so Keen on this Idea. Thanx So far . Mike

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