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  1. #1
    Join Date
    Mar 2010
    Posts
    621

    2-SIDED VACUUM CLAMPS PODS

    I'm really curious as to how these are made and the effectiveness? Does anyone own or have they tried these?

    2 Sided Vacuum Clamps Pods Vacuum Table CNC Machining | eBay

    Are they simply machined flat with a hole drilled in he center then routed for a gasket or is there more to it than that on the internals? are they a single piece of material or 2 pieces assembled together somehow?

    Adam,
    Gecko G540, Rack and Pinion Drives-X and A axis, 1/2-10 5 Start Acme-Z Axis
    4-THK HSR 25 Linear Slides, KL23H2100-35-4B, Power Supply-KL-600-48 48V

  2. #2
    Join Date
    Aug 2011
    Posts
    998
    That is pretty much it. I have it even simpler:

    - 5x5" plate from 3/4" birch ply
    - 4 slots in a star pattern (2 crosses at 45 degrees) 1/8" or 1/4" wide going completely through the plate, leaving about 3/4" border
    - a 1/2" hole routed/drilled from the side, about 1" deep ending in one of the slots
    - a piece of clear PVC hose 3/8 ID and 1/2 OD glued into the side hole for vacuum connection
    - a gasket made from 1/2 x 3/16" Frost King black weather strip on both sides (kind of memory foam that compresses down to 0.02 thickness but will recover, from Home Depot). If you cut by mistake into the gasket, you can just scrape it off with a chisel or knife and replace. It is so soft, you can even overlap short distance without problem.

    I don't have a pic of the pod itself but here is one in use. If you have only a small pump (I use 3/4hp GAST pump) you will need a few gallons reservoir for the initial suck:

    Box Joint and Dovetail CAM software here: WWW.TAILMAKER.NET

  3. #3
    Quote Originally Posted by adam_m View Post
    I'm really curious as to how these are made and the effectiveness? Does anyone own or have they tried these?

    2 Sided Vacuum Clamps Pods Vacuum Table CNC Machining | eBay

    Are they simply machined flat with a hole drilled in he center then routed for a gasket or is there more to it than that on the internals? are they a single piece of material or 2 pieces assembled together somehow?

    Adam,
    I would make these in 2 pieces that are pinned together. The inside geometry is literally a hole that goes to the center and opens up to a pin hole on either side. You can use the pin holes to align everything in a fixture for the double sided machining. After you put it together, I would tape the center hold for 1/4 NPT and put a barb on it.

    MDF or plywood would work but you will want to apply a coat of shellac to seal it. I personally would use a plastic like UHMW PE.


    Nate
    Fine Line Automation
    www.finelineautomation.com
    Fine Line Automation
    www.finelineautomation.com

  4. #4
    Join Date
    Mar 2010
    Posts
    621
    Thanks for the posts.

    Jerry, I'd be interested in a picture of one of yours when it gets off work... lol!

    Nate, that was my initial thought of design, two pieces sandwiched, I just wasn't understanding what the need was for? Similar to what I've drawn?

    I mean wouldn't it be simpler to just drill a center hole in the end and then 2 side holes?

    Maybe its for using opposite corners for holding?

    I was thinking of using some left over solid surface material I had..
    Gecko G540, Rack and Pinion Drives-X and A axis, 1/2-10 5 Start Acme-Z Axis
    4-THK HSR 25 Linear Slides, KL23H2100-35-4B, Power Supply-KL-600-48 48V

  5. #5
    Quote Originally Posted by adam_m View Post
    Thanks for the posts.

    Jerry, I'd be interested in a picture of one of yours when it gets off work... lol!

    Nate, that was my initial thought of design, two pieces sandwiched, I just wasn't understanding what the need was for? Similar to what I've drawn?

    I mean wouldn't it be simpler to just drill a center hole in the end and then 2 side holes?

    Maybe its for using opposite corners for holding?

    I was thinking of using some left over solid surface material I had..
    My only reason for 2 pieces was to do the inner hole geometry easier. Rather than having to fixture the part on it's side to drill what is a deep hole, I can just flip it over on the CNC and mill a half circle channel on each pieces with a ball nosed mill. If you want a decent size plate like a 7"x7" plus it's definitely easier.

    I think you definitely want to overlay a grid pattern on top of that diagonal. It will ensure you don't have trapped air and will also allow you to apply a gasket material to smaller squares if you need more flexibility on the size.


    Nate
    Fine Line Automation
    www.finelineautomation.com
    Fine Line Automation
    www.finelineautomation.com

  6. #6
    Join Date
    Mar 2010
    Posts
    621
    That drawing was supposed to be of just the inner holes in the "puck"..

    Makes sense about drilling on edge.

    Do you have a picture of one of your hold downs, I'd love to see what you've made.

    Adam,
    Gecko G540, Rack and Pinion Drives-X and A axis, 1/2-10 5 Start Acme-Z Axis
    4-THK HSR 25 Linear Slides, KL23H2100-35-4B, Power Supply-KL-600-48 48V

  7. #7
    Join Date
    Aug 2011
    Posts
    998
    Quote Originally Posted by FineLineAuto View Post
    ........MDF or plywood would work but you will want to apply a coat of shellac to seal it. I personally would use a plastic like UHMW PE. .......Home - Fine Line Automation
    I found MDF indeed way too porous. Even with careful sealing there seems to be always a leak somewhere. But I did not have trouble with baltic birch plywood. Even without edge sealing it is quite airtight. Plastic would work of course as well but the plywood is cheap and easy to cut or replace when I make a mistake.

    I will post a picture of the pod tonight. It is indeed made from a single plywood sheet with the slots cut all the way through. For a two-sided pod there is no real reason to make it more complicated.

    I also have one-side vacuum pods that bolt to my t-slot table and these are a bit more complicated, that means made from two 3/8" sheets of Garolite plastic and a removable thin sheet of MDF as "spoil cover".
    Box Joint and Dovetail CAM software here: WWW.TAILMAKER.NET

  8. #8
    Join Date
    Aug 2011
    Posts
    998
    Here are the pics that I promised:

    1. One-sided pods for my t-slot table. Made from 2 sheets of 3/8" Garolite (base with bolt recess and top with vacuum channels) glued permanently together. The top cover is a 1/4" sheet MDF with a couple of holes and stuck onto the plastic parts with rubber cement so that I can remove it when I happen to chop into it.


    2. 2-sided pods that I use only for an extension table that does not have t-slots (only a smooth surface, see 3rd pic):
    3/4" plywood slotted through with gaskets on bot sides. I did not bother with a spoil plate because it is so easy to replace anyway. If I happen to cut into the gasket or rip a piece out I usually patch it with more gasket tape until it gets too uneven. Then I scrape the gasket off and apply a new one.


    Here a picture of the setup with the moving extension table that I use for parts that are longer than my machine. It also shows the vacuum reservoirs (black tubes, about 6.5 gal total) and the air filters (inline fuel filters).
    Box Joint and Dovetail CAM software here: WWW.TAILMAKER.NET

  9. #9
    Join Date
    Mar 2010
    Posts
    621
    Thanks for the pics Jerry, very helpful. What type of vacuum are you using to make these effective?

    Nate, do you have a drawing of what your using?

    Any idea the type of gasket material, it looks like its some type cording that they use?

    Adam,
    Gecko G540, Rack and Pinion Drives-X and A axis, 1/2-10 5 Start Acme-Z Axis
    4-THK HSR 25 Linear Slides, KL23H2100-35-4B, Power Supply-KL-600-48 48V

  10. #10
    Quote Originally Posted by adam_m View Post
    Thanks for the pics Jerry, very helpful. What type of vacuum are you using to make these effective?

    Nate, do you have a drawing of what your using?

    Any idea the type of gasket material, it looks like its some type cording that they use?

    Adam,
    Adam,

    Go with Jerry's design. The star lines all the way through are brilliant. The only thing I would change is instead of using gasket tape I would route a half circle pocket around the edge and use a round gasket material that just pushes down into the channel.

    Regards,

    Nate


    Nate
    Fine Line Automation
    www.finelineautomation.com
    Fine Line Automation
    www.finelineautomation.com

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