Tile Gasket + MDF

Tile Gasket is a quick, user friendly, and extremely versatile workholding method. The large “tile” of perforated gasket material turns the entire surface of your AirWeights Vacuum Table into one large suction surface - delivering uniform vacuum clamping across the whole table. This is amazing for organic shapes, designs with uneven outlines, or items that would be otherwise very challenging to create a gasket for.

Simply place your workpiece anywhere onto the tile gasket surface, and it will be held firmly in that spot.
Since the tile gasket is a soft foam, you can cut below your part, for fully finished through-cuts with no tabs or onion skin.

Through-cuts should be just slightly (0.005”) below your part, barely kissing the foam gasket. This minimizes damage to the gasket itself, allowing you to use one gasket many times over.

 

How To Apply Tile Gasket Sheet to 1/4" MDF:

NOTE: The type of MDF used is critical to this approach. We recommend using ¼” thick MEDEX from Roseburg Forest Products. Other MDF materials can work, but the material density needs to be at least 45 lbs/ft³ [720 kg/m³] to function properly with your AirWeights system. This can be counterintuitive when compared to traditional vacuum table systems found on large industrial CNCs, which move large volumes of air. Our pumps prioritize pressure difference and power efficiency. If low density materials are used, the pump will not generate a high pressure differential due to excessive flow through the MDF. Higher density MDF helps to reduce this flow, allowing the buildup of a pressure difference to create strong workholding. 

  1. Place your ¼” MDF on the vacuum table and turn on the pump. Our pre-applied MDF+Tile Gasket assemblies have precision locating holes to accurately and repeatedly locate on the AirWeight. You can expect a reading of about -15” Hg while the MDF is leaking air through its thickness. 
  2. Face off the minimum amount possible from the top of the MDF. Ideally .010” (0.25 mm) or less. This is primarily to achieve coplanarity between the top surface of the MDF and your machine. If you are happy with the variation in Z across the MDF surface without facing it, you can skip this step.
    WARNING: Ensure the 1/2" steel locating pins are fully seated in the AirWeight and sub-flush of your facing depth. You may also face the sheet without the locating pins installed to avoid a potential crash.
  3. Somehow mark the orientation of the MDF after facing, if you decided to. This ensures that any Z error you accounted for is maintained each time the MDF is placed back onto the AirWeight. 
  4. Remove the MDF from the AirWeight and place it on a flat surface. Without removing the backer, place the tile gasket onto your MDF in the position you’d like to install it. Make sure your tile gasket covers the top surface of the MDF completely. *TIP: Place a heavy object on the tile gasket to maintain its position. 
  5. Fold 1 edge over to show the backer. Peel back ~3”-5” along the entire edge, then fold and crease the backer to keep it away from the adhesive. 
  6. Fold the gasket back over and place the exposed adhesive lightly against the MDF in the appropriate location. Adjust as necessary. Once the correct location is achieved. Apply pressure to activate the adhesive. 
  7. Fold the gasket sheet back the other way. Slowly peel the backer off the tile gasket, allowing the sheet to naturally lay onto the MDF. Once the sheet has been rolled on, apply pressure all around the gasket to seat the adhesive. 
  8. Place your MDF + tile gasket assembly back onto your AirWeight, making sure to maintain the same orientation as before. 
  9. Place material on top of the tile gasket. Turn on your vacuum pump and apply downward pressure to your stock. Allow 10 to 20 seconds for pressure to build. Push and pull laterally on your material to test how secure the hold is. If you are not comfortable with the holding force, do not perform any cuts.

Tile gasket tips and tricks:

  1. Minimize the amount you cut through to maintain the service life of your tile gasket. Cutting deep into the gasket, or worse, cutting through into the MDF, will cause issues and leaks for the next project. You may even choose to leave a very very thin onion skin (i.e. .005”), which will simply flake off upon removal of the part. This will maintain the service life of your tile gasket. This approach requires understanding your stock thickness very very well, especially in the location where you are setting your Z0 position. 
  2. This approach is very sensitive to flatness. If your stock material is bowed or warped, this approach may not function well.
  3. This approach is sensitive to surface roughness. For example, plywood with a very coarse grain will be challenging to hold. Smooth surfaces such as prefinished plywood or plastic sheets are ideal.
  4. This approach is sensitive to porosity. If your stock material is porous, consider a different approach or completely seal the bottom surface of your material (using sanding sealer, lacquer, blue tape, vinyl, etc...).
  5. Seal the edges and a 1 inch border on the bottom side of your MDF. Lacquer wood, glue, epoxy, etc... have all been proven methods. This helps to prevent leaks through unwanted areas and isolates vacuum to the tile gasket ports where it's needed.
  6. If you’re stock material is smaller than the surface of your tile gasket, cover any exposed tile gasket with a non-porous scrap material, such as thin sheet plastic, marker board or scraps of prefinished plywood. This helps prevent leaks in unused areas and increases holding force on your stock.