What are these marks ?

[PineLane]

Hello all...

These arc marks have started showing up very recently. The electrode has a little more cut time, but the nozzle has 4 minutes total time. I've swapped both out and the same problem still exists.

What causes this and could this be the problem with one side of the pictured long tab not completely cutting through ? It cuts fine through in one direction, but then as the z is heading back the other direction, it cuts, but not cleanly through.

Never had this problem before. Air filter was replaced, dessicate is regen'd. Everything "appears" normal...ie - same as always, except for this arcing.

Thoughts?

[beefy]

Oh damn, this is really serious

It's OK don't stress, I'm not serious

This has had others worried before but it's the way the arc is established with Hypertherm machines (it is Hypertherm ??).

This is my understanding: with no air flow to the nozzle the electrode is pushed under spring pressure onto the inside of the nozzle. To create the pilot arc the air pressure actually causes the electrode to be pushed away from the nozzle. This draws an arc which is the start of the plasmarisation (I invented that word) process of the compressed air. Once the cut is finished and the air flow eventually stops, the electrode is pushed back in contact with the nozzle interior under spring pressure.

My calculated guess is that the point of contact of the electrode / nozzle is where the mark is furthest towards the outside, and it gradually progresses to the hafnium core in the centre as the main arc is established.

I can hear your sigh of relief

If I've gave any incorrect info I'm sure Jim will correct me.

Keith.

[acourtjester]

Going with the above description maybe you air solenoid is slowing down or an obstruction in air supply and the action of the tip to nozzle has changed. That seems to be a little heavy of an arc mark.

[grindergary]

Oh damn, this is really serious

It's OK don't stress, I'm not serious

This has had others worried before but it's the way the arc is established with Hypertherm machines (it is Hypertherm ??).

This is my understanding: with no air flow to the nozzle the electrode is pushed under spring pressure onto the inside of the nozzle. To create the pilot arc the air pressure actually causes the electrode to be pushed away from the nozzle. This draws an arc which is the start of the plasmarisation (I invented that word) process of the compressed air. Once the cut is finished and the air flow eventually stops, the electrode is pushed back in contact with the nozzle interior under spring pressure.

My calculated guess is that the point of contact of the electrode / nozzle is where the mark is furthest towards the outside, and it gradually progresses to the hafnium core in the centre as the main arc is established.

I can hear your sigh of relief

If I've gave any incorrect info I'm sure Jim will correct me.

Keith.

Keith,

You hit the nail right on the head.

I asked the same question and was told it was normal as the arc start. I was told that if I was worried about the marks to just clean them a little bit with something like a scouring pad. Works for me.

The arcing line inside does not seem to cause any side effects. I cut 286 pierces on a complicated piece on 16 ga. 45A fine cut and was still good to go for more cutting.

Gary

[mdwalker]

I'm not sure what causes it but I can say from my experience with my machine that is not normal. I am running a Hypertherm Powermax 1000 and an old Powermax 800. I would say with correct settings, good clean air supply, and correct consumables you shouldn't be getting that, at least not to that extent. I'm sure Jim will see this and educate us on this.

Danny

[grindergary]

Here is a post i originally posted. I can,t find the pictures but looks identical.

http://www.plasmaspider.com/viewtopic.php?f=4&t=10675

According to Jim Colt, this was normal.

Gary

[jimcolt]

It is normal to have arc marks on the face of the electrode as well as the inside of the nozzle. These do look a little darker than normal.....which could be caused by any type of contamination in the air line, or by aftermarket consumables.The finish on the electrode and the rear of the nozzles are of a totally different texture than the ones I get that are genuine Hypertherm....maybe you have cleaned them or shot blasted them? The Hypertherm parts have a shiny smooth finish.

The electrode and nozzle are shorted electrically when not cutting.....when you start a cut the electrode pulls away from the nozzle creating a short circuit spark.....this spark ionizes the air flowing through the torch which starts the plasma arc.

Other things that can make these arc marks worse:
- Air contamination....particulates (did some dessicant powder make it to the torch?), oil, dirty fingers, water.
-Aftermarket consumables.....wrong copper alloy, incorrect dimensions, improper springrate on electrode.
-Incorrect air flow through torch.
-Using consumables at a higher than rated amperage

Jim Colt Hypertherm

Hello all...

These arc marks have started showing up very recently. The electrode has a little more cut time, but the nozzle has 4 minutes total time. I've swapped both out and the same problem still exists.

What causes this and could this be the problem with one side of the pictured long tab not completely cutting through ? It cuts fine through in one direction, but then as the z is heading back the other direction, it cuts, but not cleanly through.

Never had this problem before. Air filter was replaced, dessicate is regen'd. Everything "appears" normal...ie - same as always, except for this arcing.

Thoughts?

20140920_232051.jpg

20140920_232037.jpg

20140920_232206 (1).jpg

[PineLane]

Thanks for the replies. The help is appreciated.

Jim, those are Hypertherm parts. I noticed on a cut just before and hit with scotchbrite, re-installed and re-fired to verify if it was being caused by dirt on the electrode. Did it again, so thought it worth asking what it was...and now I know.

Thanks
Dave