Thc problems Torch just kept rising

[Knick]

Ok So I am having problems with THC. I have always used it and I have never had problems until I got this HT 65 sync.

When I first got it I started using nominal Voltage and it worked well. Then I started having issues where the live voltage was 20-30V above what Nominal was set at. it got worse and I could see the torch hunting up and down.

I did not take the time to figure out why and went back to smart Voltage. And it was good again.

I was not paying attention to voltage readings as is was cutting pretty good, not perfect but good.

Today I went to cut the first of 50 parts with smart voltage and I noticed live voltage was very high while cutting. I stopped after one part and noticed the live V was at 80V doing nothing.

I called LS and after test ting he thought the Motion control board or some other thing might be wrong. So he was going to send me the parts and said in the mean time I could turn off THC and cut the remaining parts.

So the the next part pieced fine, but then the torch started hunting then all of a sudden it just started rising and was over a 1" up and Fire control was froze. I had to hit the E-stop to get it to stop.

So I called LS back and they were closed, so I had to leave a message. I am sure I wont hear back from them till late AM and I would like to try and cut these parts if there is anyway possible as they are due tomorrow.

Even though THC was turned off, it must still been controlling the torch in somehow.

So My thought was if I take the nominal voltage Hyperthem calls for and subtract my 80v from that do you think that might work?

[ds690]

If the THC was off, it must have been the IHS lifting the torch. If the IHS circuit opens during a cut, it will raise the torch to prevent a crash. Watch the IHS indicator in Firecontrol to see if the green light comes on during the cut.

[Knick]

@ds690

it must have been the IHS lifting the torch. If the IHS circuit opens during a cut,

I just tried it and its lifting the torch, but no IHS light. this time the torch turned off but the torch kept rising. I was able to stop it with with Firecontrol and did not need the E-stop.

This was with THC turned off

[Phillipw]

@Knick I had a similar but very different issue with mine a while back. My z axis would go completely crazy. At the end of a cut it would raise too high then when it would initiate the ihs it would go up instead of down. Even manually the z down would raise. Turns out the z axis motor plug didn’t have a good connection at the control box.

I cleaned my ihs contacts with alcohol. I also cleaned the plug end of the z motor and uses a little dielectric grease on the connection and my issue when away.

I don’t think this is your issue but something to eliminate.

Another thing I noticed was when i switched to a Hypertherm my machine seemed much more sensitive to emi. My USB cable could look at the torch cable it would freeze fire control. I would also check your cables.

[Knick]

I think you hit it with EMI. I will be back as to what I did. But I also had some other issues come up during the 125 min cut session, and to what those things were. I got the parts cut but it was a struggle and they were not the best cuts.

Any ways I will be back

[Knick]

When I got the 65 Sync. I moved the VIM box from the side of the old cutter to the side of the Electronics enclosure and coiled the THC around it and zip tied it.

I did not think anything about EMI as I have never had any problems in the past.

So I uncoiled the THC cable and removed the VIM off the side of the enclosure box.

This took care of the the torch raising up and I was able to get the 49 parts cut but…

So these parts took about 2:10 secs ea to cut. I was maybe 17 or so parts in and decided to let things cool down. I waited maybe 15 mins and hit restart and it was 2 parts from the end and it stopped mid cut (Firecontrol thought it was still cutting) I had to Ctrl-Alt-Del to get control back. I was able to get the last two cut .

The cuts on most of the parts were pretty bad and required a lot of clean up. Some holes were good, but most needed clean up. The perimeter cuts were rough in places and perfect in others. The bad spots were not in the same area. Most all parts had issues and they were all different.

Material was 1/2" carbon.

Things I noted while cutting these:

While cutting these part the fans on the Electronics enclosure ramped up in speed to point I had never heard before. They were very loud, you could hear them over the Cutter fan (also on high) and the cutting itself.

When Firecontrol locked up at the end I wonder if it might have been heat related.

I will now trying using nominal voltage and see if that works again, but at this point I believe EMI was the problem. When I cut these again I think I will cut 15 pause for 15-20 mins and repeat. When pausing fire control I always feel like I am going to come back and find it reset or locked up.

I still have parts coming from Langmuir, but not sure I need them.

I will say I am getting much better at finding the spot in code where the problem was and saving the part.

I will mark this solved once I have more data.

As always Thank you for your help!

[Phillipw]

Hopefully you have it figured out.

[ChelanJim]

Good report Knick: lots of objective information.

I think there was definitely some EMI as some of your description with the cut mimicked what I had at one time. (I have always had the Hypertherm 45XP).

Just throwing some other things out there:

1. Did you try a new torch cartridge?
2. You might go into the THC settings and increase the sample size for the reaction to the voltage change. This will slow the torch reaction of deciding to hunt up or down. (One time I was having an issue and this allowed my cutter time to give an error where previously it would not go long enough before FireControl would interrupt. In my case it was low pressure to the back of the cutter.)

[Knick]

@ChelanJim

1. Did you try a new torch cartridge?

I did not as I am still learning this Machine. That was one of the questions I was going to ask the Sync guys:

Do you replace when machine tells you to?

Do you replace when hole looks out of round?

What works for you?

I am going to cut some 2" coupons and see if Nominal Voltage works again. If not I will wait till parts get here from Langmuir.

I know there has been a lot of posts about EMI, I am going to see if I can find some more tips on Prevention if I can get the search to work for me.

[ChelanJim]

I will let the SYNC guys give their experience/advice.

Until then, you could at least compare the aperture of the current nozzle to a new one. Perhaps in all of the chaos there has been some adverse trauma to it.

EMI:

This guy really made quite the system to get rid of his EMI:

Solving Crossfire Pro CUT60 EMI and Ground Loop issues once and for all

I have been chasing EMI and ground loop issues on my Crossfire Pro with Primeweld CUT60 for years. To be clear, I do not believe this is a Langmuir problem, the Primeweld CUT60 is known to be a noisy girl and was removed from their recommendations list. But that said, the Crossfire Pro electronics were not designed to have robust protection against such cutters that throw off a lot of noise. What were my symptoms? The most common was simply disconnections to the electronics during a cut. But it…

I did buy the “bullet-proof” device @Bigdaddy2166 recommends:

Problems with bevel, maybe THC

If your table passes OHM’s test, your computer or monitor will probably connect the Langmuir board to the ground. The control box may also be involved. If your table does not pass, it could be the USB shield touching the case, the isolation bushings contacting the case, etc. By no means should the control box be electrically connected to anything other than the required cables. I am willing to bet that your computer is connecting the control box to the electrical service ground in your shop via …

I can’t say if the device worked, but it didn’t hurt. I feel like it added another 0.05 seconds required with my pierce delay…but that is anecdotal…not confirmed.

[Bigdaddy2166]

I’m not fully sold on $58 consumables yet. You may try hooking up an isolated ground to the plasma cutter case. I would create a makeshift Faraday cage. My Everlast has a grounding screw on the rear to stop EMI. I’m sure you have checked the table frame to the control box. I have an elaborate isolated ground on my machines. They all operate without any issues.