TruCut cnc THC issues

[vicalma03]

Hello all I’ve been running a TruCut table for a while now and it’s been a great machine! Recently the THC has been acting weird. It randomly works for a few cut cycles and then will only travel up once it starts acting up. Also I’ve noticed it will start to travel up higher as it is cutting to the point of being too far from the plate to cut.

Once the machine starts to only travel up I have to cut power at the relay (which I assume goes to the THC) and then I can manually move the z axis down with the controller. I have no idea what type of THC this cnc uses and Im hoping I can get someone here with knowledge on these machines as it looks like this company is no longer in business.

Any ideas? I’ve attached a few pictures of the control panel.

Is it possible to upgrade to a different THC?

Thanks!!

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[acourtjester]

First thing I would do is reload the software, if you have an install disc or a backup of the original software load.
From what you describe there may be a problem with the Z axis driver with the direction motion. Since the drivers look the same for the 3 axis you may try switching the Z with one of the other (X or Y), you will need to set the switches to reflect the axis settings for the switched position.

[vicalma03]

Thanks for the reply. We have changed the z axis driver, checked wiring and used new stepper motor and they all checked out ok. In fact the new driver is currently hooked up to the z axis. I will try and reload the software. Going to see if I can find anything online which I doubt.

[weldguy]

I am not familiar with the Trucut system and cannot tell by the images what it uses for THC but it sounds to me like your THC system is not getting the arc voltage signal it once did. First thing I would do is determine what your arc voltage signal coming in is. One of those CPC connectors in your pics will be the one that your plasma cutter plugs into, and 2 of the pins on that CPC connector will be the arc voltage coming into your control box. Not sure what plasma cutter your using but below is the pinout for Powermax 65-85 showing that arc voltage can be measured at pins 5 and 6 with a voltmeter on DC voltage. Cut a long straight line at the correct cut height and measure the arc voltage here would be the first step. If you can post back with your voltage reading while cutting this line that would help.

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