I found the vacuum-former to be quite useful and interesting this week. (and I've already done riveting/welding/bolting/etc.. so I thought it would be a good tool to get to know) I've been playing around with a ADXL202 dual-axis accelerometer evaluation board lately, and I decided to vacuum-form a case for it.

First try

The ADXL board is about 2x2 inches, and on my first form I put it up on a chunk of wood that was about smaller than 2x2 - so the board actually overhung the platform. That was a MISTAKE! When the vacuum came on, it pulled the skirt all the way underneath around the smaller wood chunk - trapping the ADXL board completely. This was partially because I had let the material get too hot - so it was sagging way down, creating too much extra slack. It also bent the connector way over, bending the pins that come out of the board. I had to use the vertical belt-sander to cut it free. One thing I did right, however, was to protect some vertially-oriented pins by putting a piece of cardboard over them, as in the following photo:

Second Try

My second try was a step in the right direction. This time I cut a chunk of wood to support the board and plug. Here are some photos of my setup and results:


I wrapped up the cord, but just left it hanging in free space..


This time the plastic wrapped all the way around the cord, getting between it and the wood. This made it hard once again to extricate the part from the plastic!


I also got these folds coming up fairly close to the top of my part, meaning that I needed to either make the wooden base lower, or get the plastic less hot/droopy.

Third Try

This time was by far my most polished go at vacuum-forming. I'll let the pictures do the talking about what I improved this time around:

I taped the cord down so that the plastic couldn't wrap around it! I tied up the cord with twine too, to keep it neat and all in one place
Finally, I put paper over the cord bundle in the bed of the former, to keep any of the stray plastic from intermeshing with it


And it worked!


Pulling the part out of the plastic was still a little challenging. I ended up sinking 2 woodscrews into the bottom of the support piece, so that I could grab them with vicegrips and pull the thing out by brute force. Things that could make this easier would be:

  • a tapered base, such that no overhang is possible.
  • pulling the part out of the plastic right after forming, while the plastic is still hot
  • re-heating the plastic with a heatgun so that it's more pliable. (but be careful of overheating the part!!)

Here are some photos of my support piece (cut with a jigsaw)

top view bottom view

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