Torch stop firing

[TexasDano]

I have a TD A120. I am cutting 1/2'' mild steel. Settings I am running are: 30ipm inside, 35ipm outside, 115V THC, 100Amps, 90-100Amp cup, Cut height .16, Air Pressure 75-80psi.

Cuts the hole fine. Then pierces and cuts around the first corner then stop from an 1 to 3 inches into that side cut.

I was wondering if any of you have suggestions for what I may need to adjust or check out to get it to cut around the whole piece.

Thanks,
Dan Reed

[jmsrbrt]

I'll go first...water in your air? Intermittent grounding?

[jimcolt]

Put a pressure gauge on your air inlet....right at the plasma (see pics). Classic symptom of a restriction in your inlet airline that slowly lowers pressure while cutting. Your plasma system has an internal pressure switch that will shut down the cutting arc if inlet pressure drops much below 85 to 90 psi...this will likely occur when the torch is cutting (drawing air), and when the cut cycle ends the pressure will very quickly build back up. Watch the gauge while air is flowing at the torch.

Could be:
-restriction from filter or separator (clogged, saturated)
-air hose too long, too small of an ID
-too many fittings, couplings on the airline.
-ice buildup in airline restricting flow.

Jim Colt Hypertherm

powermaxpressuregauge 001.JPG

[TexasDano]

I have the torch ground on the 1/2" plate. The plate is clean of rust and oil. I just went to double check the air quality. It is dry. I have a refrigerated dryer and 2 particulate and mist separators in line before it.
I havent had any other issues with torch going out during cuts, only on this 1/2 inch stuff. First time cutting it on the table.

Thanks for the advice Jim. I am going to put the regulator on and check it out. Let you know if it works.

[TexasDano]

Well guys, I put a regulator/guage at the plasma air connection and opened it full. Supply pressure never fluctuated from the line pressure of 105 psi. To check it I tried to run another part, and it stopped firing at roughly the same spot.
Puzzled I am.
Dan Reed

[jimcolt]

What do you mean by putting a regulator on the inlet? I suggest a pressure gauge....a regulator likely will create more of a restriction. You need to measure the pressure right at the inlet. I have never seen a plasma cutter that did not show a pressure drop at the inlet when the air starts flowing at the torch....

Is there any way you can increase the inlet pressure up to around 120 psi....then cut a part?

Jim

Well guys, I put a regulator/guage at the plasma air connection and opened it full. Supply pressure never fluctuated from the line pressure of 105 psi. To check it I tried to run another part, and it stopped firing at roughly the same spot.
Puzzled I am.
Dan Reed

[TexasDano]

So I remove the inline regulator and installed 100 psi gauge. Pressure never under 100. it's still stopping in the same rough area. I made line pressure 115 psi.
What should I look at next, could it be my software or my post. It never stops exactly the same place so I doubt it is in the software.
Everything looks good on the tip, the electrode had a discoloration. I brushed it off. Looks fine.
Don't know what to look at now...

[TexasDano]

Here is a pic of a manual jogged cut. I set torch cut height @.160" 100amps, 100amp tip, 32ipm, all the same as the machine cut when the torch was stopping. So I ran it manually in jog mode so that I could re fire the torch and keep cutting to see what happened. I cut 12 inches before the first arc stop, restarted and got 6 inches of cut before arc stopped, then refired and got 3 inches of cut, Then I just had 1/4" to finish cutting the drop off of the plate and it did that with out stop after refire for the 4th time to get a 22" cut through the 1/2" plate. I noticed a pattern here. But what it means I don't know yet Hah.

[JJsCustomDesigns]

Does Mach3 post an error code when the torch goes out? Back when i first got my setup. I kept getting " Emergency E-Stop Requested " . The torch would be moving along and just quit. I could get it to work intermittently but couldnt cut a part in one fire. I dunno if this will help- just throwing it out there. Check your earth ground. I used 1/2 rod when i was having my problems. i jumped up to 5/8" rod and 3/8" copper from the rod to the table grates. PlasmaRoute said i was getting too much interference. I havent had the problem since.

[TexasDano]

Thanks JJ, I'll check it out. I'll make sure I have good grounding of the table. It's wierd that it cuts half as much before shutting off again. And no estop request just arc stop and feedhold because of arc stop. I'm checking everything wiring, air supply, grounding.

[muzza]

Not sure what system your running ,if it's Mach 3 check your "cut profile" if this is not set correctly it can do just what your experiencing.
Murray

[Larry83301]

Sounds like a duty cycle problem to me. What is the rating on your torch?

Larry

[TexasDano]

Larry, it is rated 100%@100amps and 80%@120amps. Also states can change if input AC is less or output DC is greater. I checked input, phase 1 and 3 are 120v AC and phase 2 is 240. 240 across ant set of legs. What do you think?

And Muzza, I am running mach 3, would the cut profile you speak of also cause a problem at lower amperage cuts? Because I can cut a 75 inch cut strait through on 30 amp 16 gauge cuts.

[muzza]

And Muzza, I am running mach 3, would the cut profile you speak of also cause a problem at lower amperage cuts? Because I can cut a 75 inch cut strait through on 30 amp 16 gauge cuts.

I'd suggest if your cutting the lighter material ie 16 gauge fine it could very well be you are not cutting with the correct cut profile.

Do you change your cut profile when you change your material ?
What does your "Tip Volts" DRO show when your cutting and when it stops?
What are your upper and lower fault limits set at?

Murray

[TexasDano]

The information you are asking is stuff I don't know. I am looking all of this up in the mach 3 manual right after I post this. Is the cut profile the one I select when I load the Mach3? I have 3 options when I first open it. Are you saying you have several of those set up to choose from depending on thickness?

[muzza]

Ok Dan, this should be your Mach 3 screen (image from cadcnc site)
The top DRO in the gold section is your "tip volts" reading

In around the middle of the screen you have the "cut profile" button, click on that and you get this screen (again from candcnc site)

You can see there you have on the right side "upper and lower fault limit"

refer to these drawings and and phone you on your cell as per PM, just have to work out international prefix to call from here.
Murray

[TexasDano]

I have no option for saved cut profile or anything like it on any display. My outfit comes from plasmaroute, it runs mach3. My screens look different. And for thc control and torch button window I only have anti dive button and some leds for torch signal stuff.

[TexasDano]

So I have tried cutting at 80 amps on 1/2" it did same torch stop. Then I tried 80 amps on 1/4 inch same torch stop.
Next I tried 60 amp on 1/4" and It cut fine. So I cut 3 of them with no stops nested no problems. Does that cancel out air issues being that the 60 amp 1/4" setting ask for more pressure than the 100amp settings?

[muzza]

Didn't see those pics when i read your post earlier.
The screen shot you show there is totally different to what I'm familiar with but if you go here http://www.machsupport.com/ the top screen shot looks basically the same. There are also links to support, tutorials and forum which may help you out.

As your problem goes away when your load requirement drops I still feel it has to do with presets which are stopping the process when you go outside them just don't know where you have all that sort of stuff in your setup. Sorry I can't be more help, I would expect PlasmaRoute would be the ones with the answers.

Murray

[TexasDano]

Update, with the machine amp setting on 60 the amp meter on the work clamp read 44 amps. I had to up amperage to about 72 or 73 to get a reading of 60amps.

Still working on getting cut of any length at 80 plus amps.
Dan Reed

[TexasDano]

Thermal Dynamics is going to swap it out for a new one. So I'll be slicing steel in a week or so.

THanks to everyone who had input on this problem. All of the advice I got allowed me to check things out proper and be able to give good information to the guys over the phone and handle it quickly.

Glad it being worked out
Dan Reed