Thermoforming Machine Low Amperage Systems Test

We got far enough wiring (and re-wiring) the thermoforming machine to perform an integration test of the low-amperage parts of the machine. This covers almost everything except the heating element.


On the previous test of the compressed air subsystem, we found a leak in the air tank. The leaky tank has since been replaced and this will be a test to see if it works with everything else.

The vacuum subsystem had also been partially tested earlier. For the previous test we only got as far as the vacuum table solenoid. This time we also have the vacuum lines between the solenoid and the vacuum table.

The relay panel had been tested with the following configuration:

  • 24V bench power supply as the input.
  • Manually connecting the control wires in turn like an old style telephone switchboard.
  • Multi-meter reading the output.

This time, the test will put the relay panel in a more realistic configuration:

  • Power will come from the 240V AC to 24V DC power supply on the DIN rail.
  • The control signals will come from the manual operation toggle switch panel.
  • And the most exciting part: the outputs are going to the actual air and vacuum components!

There was much anticipation and trepidation when the power switch was thrown the first time and we see LED indicators on the power supply indicating the system was live. Every switch thrown was a “Will it work?” mystery. The test did its job, exposing a few wiring errors. Fortunately none of them were damaging mistakes and all were trivial to fix.

At the end of the evening, we could control everything except the heating element using the manual operation switch panel: Move all the air cylinders, open and close all the air valves, and activate the electromagnets that hold the frame closed.

We still have lots of things on the to-do list, including some air leaks to track down and fix and plenty of wiring tasks. And there’s still the big intimidating heating element looming in the near future. But all in all, a wonderful morale boosting step on the journey to completion.

(Cross-posted to

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