Tux-Lab Thermoforming Machine Disassembly

One of the projects on the Tux-Lab to-do list is to revive a thermoforming machine. Purchased cheaply in non-working condition, it has potential to enable some very interesting projects. It has been gathering dust while waiting for enough interest from enough people to reach critical mass to start the project. I think we finally reached that point! We pulled it out of the corner it’s been sitting in, and merrily started pulling everything apart.

Disassembled

I thought we would document the original condition as we pulled things apart, but it quickly became apparent there’s no “original condition” to document. The wide range of age and quality of components made it clear it has seen continual modifications in its decades of service. The decision was made to go all the way back to fundamentals.

The bottom cabinet held the air machinery: a vacuum pump and an air compressor, each with an associated accumulator tank. They had all been bypassed with external connectors, which was not a vote of confidence in their functionality. We were hopeful that the previous owner(s) just wanted to reduce noise and vibration by hooking into their shop’s existing compressed air and vacuum lines.

The vacuum pump turned and could pull 26 inches of mercury, which is quite acceptable. The air compressor pushed out 40 psi, which was rather was less so. Fortunately a disassembly and cleanup was enough to help it push 100 psi. The two air tanks are question marks.

There are two air cylinders in this machine: One moves the thermoforming frame up and down, the other  moves the heater front and back. A quick test of both revealed they move and no air leak hissing was audible at either of their end positions.

The thermoforming frame was designed with two electromagnets to hold it closed. We assumed the magnets were broken because somebody installed some Home Depot quality mechanical latches. But we were able to energize the coils and feel it hold. Maybe the failure was in the control circuitry, maybe it doesn’t hold strongly enough for some task. We’ll find out for sure later.

Latch

The brains of the machine are the clearest indication of the age. We see a lot of discrete logic components and no indication of a microcontroller at the heart of it all. The control panel has a button “Automatic” and we wonder what that used to do. For the moment we will not worry about it: the initial milestone is to get it up and running in manual operation mode. If we get around to implementing an automatic cycle, we’ll pull in an Arduino or something modern to orchestrate the various bits and pieces.

Brains

On the assumption that old air hoses and fittings will be leaky, they will be replaced with new parts. The air valves should still be good and will be used until proven otherwise. Same for the big honkin’ contactors (240V, 40A) in the back to control the heater.

Orders have been placed for replacement parts – once they show up we can install them to get a better idea of how everything will (or won’t) work together.

(This project is cross-posted to Hackaday.io)

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