Cut50d

[Ray]

It was the description of the rhythmic cutting in and out that made me ask. I was thinking a kink in the line inside the machine or the torch.
I think I still have your number in a PM, are you around and awake?

[performance]

Ken,
If I remember right, way back, when we had the PT 31 torches, we had some issues with some of the replacement, and stock consumables.

[kenwhite]

Mark, I think I have the SG-55 torch used on the 60A units - purple ceramic cup. I will take a set of new consumables in to try and see if they make any difference.

Ray, I will be at the college until late tonight, so you can try to call if you want. However if I am in class, I won't have my phone on me.

Thanks guys,

Ken

[kenwhite]

OK I did some more testing.

Replaced electrode, tip nozzle, swirl cup, and shield cup, no change.

Noticed the spark gap glows blue before the start and goes off when the arc goes off.

Re-adjusted the gap out to about 0.05" and there was no change.

Adjusted the current control potentiometer and as the current is increased the arc gets brighter and turns on/off at a faster rate.

As the current is decreased, the arc become blue in color but stays steady on - it will not cut it just scores the metal.

Any ideas?

[kenwhite]

Oh, and I made a mistake on my torch, the plastic is red and the shield cup is white, so I'm guessing it is the lower rated torch and not the SG-55...

:-(

[Oleg]

Oh, and I made a mistake on my torch, the plastic is red and the shield cup is white, so I'm guessing it is the lower rated torch and not the SG-55...

:-(

kenwhite

please take a picture of that torch , i think its older version 80a rated torch !

[performance]

Ken,
I am taking it back to the consumable issue. Some of the suppliers we had made some goofs in the clearance on those torch consumables. After a while, a few would "wear" in and stop the sputtering....at least that has been my experience. Simply changing one from the same batch might not fix it. The only other possibility that would be a common issue, is the ground clamp has some resistance issues causing the unit to sputter in and out. The changes in the gapping making a difference suggest such a problem.

But you said initially it worked OK...What was the exact problem before we got you to putz with it? You never said.

[kenwhite]

kenwhite

please take a picture of that torch , i think its older version 80a rated torch !

I will shoot a picture of the torch and consumables today with my phone.

Ken,
I am taking it back to the consumable issue. Some of the suppliers we had made some goofs in the clearance on those torch consumables. After a while, a few would "wear" in and stop the sputtering....at least that has been my experience. Simply changing one from the same batch might not fix it. The only other possibility that would be a common issue, is the ground clamp has some resistance issues causing the unit to sputter in and out. The changes in the gapping making a difference suggest such a problem.

But you said initially it worked OK...What was the exact problem before we got you to putz with it? You never said.

Original issue that has gotten worse.

...My arc quits intermittently after a few passes, any ideas? I have clean dry air at 60 psi continuous with no leaks, and new consumables, so it appears electronic...

The ground clamp (DC +) is solidly connected to the front female plug and PCB, and the clamp end is solidly connected to the cable, so unless some strands of wire are broken inside the cable, the ground should be good.

The consumables appear to fit tightly into the torch but maybe something is loose inside the torch? I can take the torch apart and take a look if you want.

Thanks,

Ken

[kenwhite]

kenwhite

please take a picture of that torch , i think its older version 80a rated torch !

Here you go...

[performance]

Ken,
If the unit has been sitting up for a while, natural oxidation occurs between the contact surfaces between the cable, the connector and the clamp. It would be a good idea to pull the boot back and check there, and remove the lug from the clamp and polish up the surface, though I still suspect consumable issues.

Just because its tight doesn't mean its not a clearance issue. Too little clearance would explain the wider gap setting working better.

AGAIN, explain the "symptoms" you were experiencing with this unit BEFORE you adjusted the points...The explanation "needs some alignment" doesn't give us enough to go on. IF you can give us additional symptoms, then it will help.

[Ray]

Mark, I think Ken is probably an old school electronics tech, the term was originally used in reference to old TV’s and was carried on the 2-way radio’s for a bit (Maybe still).
Basically the term is synonymous with “Tune Up”.
Ken,
That is one of the earlier 80A torches, it looks to be in good shape, but they are known for having issues. And what is happening does sound like a possible torch issue.
If you can give me a call and I’ll help you inspect it, they seem to be more susceptible to damage from moisture in air line than others.
Sorry it seems we've been playing phone tag, but if you call and I can't pick up, leave your number and I'll call you right back.

Thanks,

Ray

[kenwhite]

Ken,
If the unit has been sitting up for a while, natural oxidation occurs between the contact surfaces between the cable, the connector and the clamp. It would be a good idea to pull the boot back and check there, and remove the lug from the clamp and polish up the surface, though I still suspect consumable issues.

Just because its tight doesn't mean its not a clearance issue. Too little clearance would explain the wider gap setting working better.

AGAIN, explain the "symptoms" you were experiencing with this unit BEFORE you adjusted the points...The explanation "needs some alignment" doesn't give us enough to go on. IF you can give us additional symptoms, then it will help.

Mark, I did explain my symptoms -> see posts 5 and 8 and I even quoted it again...

The arc was intermittent and would cut-out after a few short cuts - I was cutting 3"wide, 1/8" thick metal.

Now the arc cuts out, on/off, when I start a cut...

[kenwhite]

I am home right now and my box is at work. I will try to call when I'm at work so I can look at it while talking to you. You should still have my number, I PM'd t to you a few days ago...

Why is there a blue arc between the points when the box is on, but it is not being used? Why does the arc between the points stay on when the torch arc is on and then go out when the torch arc quits while being used?

The symptoms sound to me like it might be a cold solder joint on a PCB...

[performance]

This is a high frequency only torch/unit. The points should energize when the switch is pressed and a small "blue" arc should be seen for a split second before the arc is established. Dirty metal, rust, or other forms of oxidation are enemy #1 of regular HF units without a pilot arc. IF there is any rust, or paint present, a slight blue arc may be seen jumping around when you touch down. The cut may be lost as well if a bad patch is encountered. This is the downside of this type unit, if this is similar to what you are reporting. The points should deactivate when the torch arc is established. If the cut/arc is lost, then you will have to restart the torch manually.

[kenwhite]

The metal is clean and new, the air is dry/clean and at more than enough psi/cfm, and the consumables that were replaced look like new - see the picture I posted...

If the trigger is held, and the torch is making contact, the plasma turns on and off at a rate controlled by the current pot.

It worked intermittently for a half dozen cuts r so and now it doesn't cut at all...

[kenwhite]

...If the cut/arc is lost, then you will have to restart the torch manually.

No problem with that, the arc is always turning on/off and on/off and on/off at a rate controlled by the current control pot as the torch is contacting the metal...

So why do you guys think it is a consumable problem again?

I really would like to get this fixed...

[kenwhite]

Sent an official e-mail requesting support since we appear to be running out of ideas. If anyone else has any ideas, please let me know. Thanks,

Ken

[kenwhite]

Got an e-mail back from support and will shipping it to MN for service. I will update this thread once I get it back. Thanks everyone,

Ken

[performance]

Ken,
Tolerances in the torch must be exact for things to work. IF it is consumables (and usually it is), no servicing will work. You can't just judge if they feel "tight". The real dimension is from the end of the electrode to the inside face of the nozzle. If that is off by a tiny, tiny amount, it will not work correctly. Any number of things could be the issue. The consumble height could be off slighly, or the shoulder machined too high or too low. The inside face could be a hair off as well. Just because it seats well, doesn't tell you much. The only way is to change to a newer batch of cons to try it out. The fact that changing the spark gap affected the starting tells me that you could have a clearance issue inside the torch head, making a longer gap necessary to create the spark.

[kenwhite]

Mark the arc starts fine, it just won't hold -> it cycles on and off over and over again when the switch is closed and the torch is touching the metal. It will stay on at the minumum current setting, though it is blue in color, and will cycle very fast and is very bright yellow when at the highest current setting.

I have a set of ten electrodes and tips, and three swirl and shield cups, that came with it that I can try.

But it did kind of work initially, it would cut a piece or two of metal before the arc would become intermittent, and now it is totally intermittent.

The consumables I replaced look new but if you really think they are the issue, then please send me a new set of consumables and I can try them. However, I am having a hard time understanding why the consumables would allow the arc to start and then cause it to extinguish immediately after.

Do you guys want me to shoot a video of the operation?