"Issues with Proxxon Foam Cutter" Topic

So I scratchbuild and bit and build terrain and use my Proxxon Thermocut a lot. Just yesterday I was using it and I noticed the power seemed to cut out intermittently making for not so clean cuts. (You can hear the slight hum going off and on)

I assumed it is a short somewhere. There are only two wire involved and the solder joints on them seem pretty solid. Perhaps, a short or bad connection in the power supply? So I'll have to take the box apart underneath the cutting platform and have a look. In the meantime, does anyone else have any ideas? Thanks in advance

You seem to have it pretty much covered. Don't forget to check the power cord/lead from the wall socket to the foamcutter and the connection where it goes into the box – these can take a hammering when setting up/putting away and while in storage.

Not a "short", but an "open", which causes a loss in power -- the hum stops because the current stops flowing. With a "short circuit", the hum would increase, as current flow increased.

If you are not familiar with electrical troubleshooting, contact the factory for assistance. The 120 VAC in the USA is dangerous, but the 220 VAC everywhere else, is twice as dangerous. Even the US line voltage is enough to kill a Human Being, so proceed with caution!

If you have a Voltmeter, check for voltage at the two wires connecting to the the nichrome wire, which does the cutting. A cold solder joint can act as an intermittent "open", as you describe. Measure the voltage from the copper wires, just after the insulation, then check the solder joints, to see if the voltage is present at both points, wiggling the wires to see if the voltage falters (bad connection, broken wires).

Check the wall cord, which plugs into the Power Supply, to make sure it is not loose (can't remember if it plugs into the Power Supply, or if it is permanently attached to it -- can't come loose…). Try wiggling the power cord to see if the hum cuts out: whether it is hard-wired, or plugged into the Power Supply, this will check for a bad connection. Cheers!

If you're working with the power supply plugged in, you need a thick rubber mat to stand on. Check the resistance across it to be sure it will protect you, and don't touch anything while you're working (tabletop, case, etc.) that might ground you.

I use mine incessantly, at times I had noticed that the wire occasionally "goes cold" in mid-cut. I spoke to friend who is a bit of a whiz at electronics and he checked mine out. The first thing that he did was to twist the temperature setting knob from 0 to max and back several times. He said that in his experience rheostats can accumulate corrosion if left at one setting too long and the best way to clear the contacts was to min-max them a few times a month. I do this twice a month now and haven't had a bit of trouble over the last two years (mine is going on five years old now and gets daily use)

Good luck!

Bowman, how long have you had your Proxxon.
They have a 2yr warranty. If you are under that time contact Proxxon directly to take advantage.

Grimm

Thanks for the help everyone.

@Anton, Never thought of the rheostat so I'll try the "min-max" movement of the temperature setting knob.

@Grimmnar I think I've had it a bit over two years….darn.

@Bsrlee, Sgt Slag and emckinney well I'm competent enough to try to jiggle the power cable, but if I have to open the electrical box, I'll leave it to a buddy. I know enough not to work on electrical appliances while they are plugged in and that's about the extent of it.

And I guess I meant "open" all along. I never heard that term used, but it is the correct meaning.

Thanks again.

So Gents,

I think I solved the problem.

Firstly, good luck if you ever have to get into the electrical box. The screws are placed so tightly, that I stripped some of the Philips heads trying to get them loose.

So while I had the Proxxon upside down I noticed the cutting wire wasn't showing through the hole where it is clamped in place. The electrical wire goes to this metal housing to complete the circuit. The wire seemed tight and clamped. But I undid the locking screw, inserted the wire deeper, and locked it in. Now it seems to be working normally. The wire was engaged enough to be locked by the locking screw but not enough to complete the circuit continuously.