Misfires on pierce

[whiskeymike]

What are the main cause of misfires? I have a part I'm making, all nested up, cutting several at the same time. Everything is cutting good and clean. The out of the blue, a pierce arcs and then dies in 1/2 a second. I'll advance to next cut and it carries on fine.

What should I look at to troubleshoot?

[urbnsr]

What cutter do you have? Does the cutter report an error code/message after one of the misfires?

Paul

[whiskeymike]

I have a HT 65, using 45a Fine cut mechanized consumables. No errors lights on the HT65 and nothing I saw in Mach 3. I hit the torch fire button and it advanced to the next hole and cut fine. I then re-ran the cut since it was the first hole to cut and it ran it just fine. As mentioned, it's fairly infrequently, but I'd still like to avoid it if I can.

I've noticed that my nozzle is getting a bit dirty/tarnished, I think from a bit of the water splashing up. Is that okay? or do I need to pull it off and clean it up occasionally. So far, I've only cut about 2 sheets, so I don't believe the consumables are anywhere close to be used up. (At least I hope not)

[urbnsr]

I have the 85. It misfires occasionally. Not with finecuts (yet), but both 45 and 65 amp standard mechanized setup. When it does misfire, my controlling software (not Mach) thinks the torch is still firing. My cutter's LCD display will show a 0-30 error code and I don't think there is any error light on. If I restart the gcode, it usually fires and goes on until the next time. Sometimes it doesn't happen again during the job, other times it does.

I seem to notice more misfires when the humidity is high and the shop isn't air conditioned. I have replaced all consumables, but during these bouts, it doesn't seem to mater if I'm running used or new. I didn't have any misfires during the first part of the year while it's cold here.

Paul

[wickedinhere]

Dry air is a must for plasma cutting i live in Louisiana and humidity plays a big part. I have to run a air dryer or i have all kind of problems from Misfires to consumables short life. I learned quick that a air dryer is a must down south.

[gblaylo]

I'm running a HT 65 and had about eight misfires this past Sat. on the same sheet, It had just finished raining and the humidity was way up (Alabama) plus I had just added water to the table and had the level a little higher than normal. The misfires all occurred at touch off
and happened to be in water or a really damp area of the sheet. I used a blow nozzle to help clear the water at touch off and the misfires went away. I had many small pierces with lots of little drop outs which contributed to the water collecting on the sheet.

Gary

[whiskeymike]

I have an air dryer and desiccant filter, so I don't think I have moisture in the line. I may have had some water on the sheet from bubble up. i'll watch for that.

[OTHill]

My biggest problem is misfire on pierce and code 30 on my hypertherm 65.Don't think I have ever cut a whole day without. Usually if I take my consumables out and spin the electrode in the nozzle a few times with considerable force( just by hand) I can cut again for a while. It seems to make connection again. Don't know if this makes sense. No moisture problem here. Don't think I drain more than a pint of water out of my compressor a week. I have adequate filteration also. Including a TP filter just before the plasma cutter. New consumables always fix the problem for a while but the glitch happens long before my consumables are shot. I have just been trying to live with it.

[lelyea]

Mike -

HEY - I dealt with this one!! I did three things to fix it, unfortunately all at once. You could try them one at a time.

I was using the clamp for the ground off the HT. Took that off and bolted it to a tab on the rear-most slat.

My table was too full of water. I was 1/8 below the top of the slat. Changed that to 1/4, maybe 3/8 from the top of my slats.

My 25 ft ground cable was coiled up. I stretched it out in a straight line and curved it back around 12 inches apart and didn't let it cross itself.

FIXED.

I am going to chop off the ground cable - just haven't gotten to it yet.

Len

[jimcolt]

I run a downdraft table...usually get 1200 to 2000 starts on a single set of consumables before any misfires. Water trays/tables do affect cut quality and consumable life. great way to control fumes, but not the best for the process!

Jim

[Stout]

I used to get misfires on my PM1250 due to friction between the electrode and the swirl ring. They just start to stick. A new swirl ring seems to fix it.

[gary42095]

With fine cut, Pierce height and cut height are more critical if I remember correctly Jim has said several times. As well as clean dry air with proper pressure.
I get an occasional misfire with fine cut. Mine I think it's more deflection of the steel on touch off to the point where Pierce is too close to plate

[BTA Plasma]

The wrong pressure preset plays havoc with pierces when using fine cut.