Airtable part 5: Insertion of ball valves

In order to regulate the air flow, you need to place in total 28 ball valves in the corresponding predrilled (8mm) holes in the top plexiglass plate. The valves restrict the air flow to only emit air below the moving platform. The air can flow out when the ball is pressed down by the platform. Because of this, the set up only works with platforms which have a flat ground surface.

Step 1: Prepare ball valves

Now build 28 ball valves. We recommend you to make a few more.

For one ball valve you need 3 components:

• 3D printed ball sleeve (STL file below)
• 3D printed ball fixation (STL file below)
• Acrlyic glass ball

In order to build a valve, you need to put a acrlyic glass ball in a ball fixation and insert a ball sleeve from the same side. A ball can only be inserted from the thiner side of the ball fixation.

If your ball sleeve in the ball fixation is a bit lose, you can use some Glue (acrylic glue) to fixate it.

The balls must be able to move easily in these sleeves, but must not lose too much air, otherwise the valves will leak. Therefore you need to check which 3D printed ball fixation and which ball fit together the best. Additionally it's important to clean the inside of the sleeve from 3D printing artifacts. Most likely are the printed sleeves to thin for the ball, therefore you need a 7mm plexiglas drill to widen it. Since this step requires a high degree of precision, a drill rig and good fixation are needed.

• The drill rig is required as it allows the drilling depth to be adjusted so that all balls have the same height under pressure.
• Recommended remaining depth after drilling when drilling from the thiner to the wider part of the sleeve: 1mm

Print settings used for testing with a good result at a Creality Ender-3 V2

• Layer height: 0.10 mm
• Infill: 60%
• Nuzzle temperatur: 200°C
• Support: None
• Raft: No

Placement of ball valves

The 28 ball valves get placed in the top plexiglass plate where 28 holes with a 8mm diameter are already predrilled. Insert one ball valve in each hole and make sure their height matches with the plexiglass plate. Maybe you need to readjust the countersink drill.

Make sure the ball valves are tight placed in the holes. We do not glue the valves to clean them later. Access the valve by pulling it out with a hook and pliers.

Step 2: Glueing of the bottom plate

After connecting the air table with the framework and inserting the ball valves there is no need in accessing the inner box, so we can close the box. The bottom plate is meant to disconnect first if the pressure in the box gets too high. Therefore the bottom plate is not screwed.

• Again it's necessary to degrease and remove any dirt at the glueing surface before glueing.

• Line up the long side of the box with the long side of the plate, there must be no hole for air flowing through.

• Glue (acrylic glue) the not predrilled bottom 480mm x 326mm plexiglass plate below the table box. It's recommended to put the glue on the 8 mm wide sides and not on the bottom plate.

Wait for the glue to be dry before going to the next step.

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