Faulty Consumables?

[Charlie10]

Semi-long story incoming... First, I'm not trying to disparage Hypertherm because they normally put out high quality stuff. Rather, I'm just trying to figure out if this is indeed my problem. I've been sporadically battling the issue of cuts not going all the way through the sheet. I've actually posted on it before and have messed with a lot of variables but nothing seems to effect it one way or the other. It's not a problem the majority of the time, but every now and then it causes me to scrap a bunch of steel. I think now I have narrowed it down to the consumables as that's the only thing that changed in this instance.

I'm using a Hypertherm 45XP with finecuts on 11ga steel. I was cutting a sheet of parts with no issue and noticed I was starting to get excessive bevel, so I stopped the program and put in a new electrode and nozzle. I resumed the program and immediately I started getting incomplete cuts and excessive dross. The next 3-4 parts with the new consumables all did not cut through and were sparking out the top. I put the old consumables back in just to see and resumed with no issue anymore except the bevel from being worn out. Then I tried the new electrode with the old nozzle and started getting incomplete cuts again. Then I tried a different new electrode from the same package and the problem persisted. So it appears to me that I have a batch of bad consumables, particularly the electrode, if it's possible that would cause this problem. And that when I have had this problem randomly in the past, perhaps it was the same thing with having the odd consumable that wasn't quite to spec. No other factor changed, same sheet of steel, same cut specs.. So I'm just curious to hear if anyone has any thoughts on this or similar experiences.

In the picture the part on the left is with new consumables, part on the right is with the old. You can see the left has a lot of welded looking cuts while the right has clean cuts.

plas ex1.jpg

[acourtjester]

The fine cut consumables have given some people problems, I am not sure but 11Ga. may be outside this range of fine cut. I would check the manual to see what the chart says

[Charlie10]

The manual says up to 10ga (their website still incorrectly says 3/16"). So it is within its capability. And I cut 11ga pretty regular with good results, it's just every now and then that it gives me trouble.

[SegoMan DeSigns]

Wasn't there another thread where cut quality was tracked down to loose parts in the torch body? How's your o-ring looking?

[acourtjester]

I had to change out my "O" ring the other day first time
The part number for the "O" on the Duramax torch for the 65 is 058519 Don't know if its the same on your torch
and the silicone lub is 027055

[Charlie10]

The thing is it's doing it with one set of consumables and not the other. And has done it randomly in the past. So I wouldn't think that's it but I'll check it out. How long had you used your O-ring before you changed it?

Edit: O-ring looks fine.

[acourtjester]

I am not a heavy user so I cannot really give you a good answer. But the day I had problems I was switching between the fine cut and 45 amp nozzle a many times. The "O" ring I took out did not look bad, I may have been crud too. I just cleaned it good and replaced the "O" ring and put the silicone on the ring and the inside of the adapter back to nice cuts again. Are you using the "Copper plus" electrode?

[Ironken]

I cut a cubic shitton of 11g and have had this issue as well. Per Jim Colt and loosely paraphrased.....NEW finecut consumables are known to have an issue getting thru steel when new especially if there are high silicon pockets in the steel. The solution is to increase cut height. Jim explained why but, I will just chalk it up to some witchcraft. I have found that if I increase cut height to .070-.080 and increase the THC voltage accordingly (1 volt = .004, so to go from the book .060 to .070, I increase by 3 volts......for example on 11g @ 45a with finecuts book spec for voltage is 78v, I increase to 81v) the issue goes away. After some time cutting and I see that a dimple is developing in the electrode, I go back to straight book specs with no issue.

FYI, I do not have a tool set for 11g and run 10g specs.

[motoguy]

Jim Colt will chime in to tell you to run your Finecuts at a greater cut height than book. .075 or so vs .060 of the book. You'll have to check on your table to see what voltage increase gets that height for you, but I believe he suggests 5-7v increase. After the nozzle has "broken in" (a couple thousand inches of cut) you can go back down to the .060 cut height. I've heard this same info from other users as well.

Personally, I had to reduce the feedrate by 10% in order to 100% fix the lack-of-penetration issue. On 14ga, I run 200ipm, 88v. Book specs are (I believe) 225ipm, 82v. Don't know what the settings would be for 10ga, but running the straight-line test at .075 should get the #'s for you. Jim is adamant that this is not the correct fix, but it worked for me.

This is a 'known issue' with Finecut consumables. Finecuts are also more sensitive to airflow/moisture than standard nozzles, so any issues with that may show up here as well. The CopperPlus electrodes (which I use/highly suggest on .5" or thinner material) are also more sensitive to airflow issues. Meaning, if you combine the CopperPlus electrode with FineCut consumables (as I do), you're increasing the odds of having an "issue". Finecuts are also more sensitive to material thickness variation, and metallurgy.

As Jim has said in the past, the book specs are dead nuts on...for the piece of material HT tested, on the table they used for testing, with the humidity they used for testing, etc. IE, the specs are correct in the lab environment, but may vary slightly for your particular situation (material thickness variation, material metallurgy variation, air quality variation, table THC variation, etc).

I suggest FIRST raising your cut height to .075-.08, running a straight line test, adjusting the voltage, and seeing if that corrects the issue. If not, I'd then reduce your speed 5-10%, run the straight line test, and run the corresponding voltage. That seems to have permanently fixed my "lack of burn through" on 14ga material. The caveat being that slower cut speed = more dross, increased heat in material (negligable, IMO), and increased kerf width.

[FazQuaz]

I cut a lot of 10 Gauge and gave up on the Finecuts. I tried all of the above solutions and always had some problem with it not cutting all the way through. The solution for me was to use the normal 45 Amp stuff. The Kerf difference between the two is miniscule and I never have problems with regular 45 Amp. I'm not sure why I tried so hard to make the finecuts work in the past.

[East German]

Hello

I also have the experience that not all nozzles and electrodes last the same length.
I had skips last week at about 1200 start and 2 hours cutting time. I've swapped the electrode for another used one and now I'm at 2000 starts and it still works very well.
However, they are not fine-cut consumables.
I mean that at 800 to 1200 starts small problems appear and then disappear again.

How many starts and cutting time do you manage with 45 A ?

Peter

[Charlie10]

Thanks for the feedback everybody. All good information. I am not using copper plus. I have slowed my speed and tried the cut height suggestion, but as FazQuaz experienced, it has minimal effectiveness. Also, I'm always fighting taper on plasma and increasing the cut height only makes it worse. The "break-in time" for new consumables is interesting to know, and now that it has been mentioned I would agree that is the case. It is odd though that I have many times put new consumables on and went right back to cutting with no issue, so there must be variation in either the consumables or the steel. Whatever the particular composition is of steel that makes it more difficult to cut, maybe sometimes it requires break-in time and sometimes does not. This last case is the worst I have experienced with this issue, but the old consumables cut it fine. When Finecuts are working properly I get better results than with standard, but they do seem a bit finicky.

[acourtjester]

This shows one of the great things about Plasma Spider, you find out your not alone and the answers seem to help understand variables that can pop up. You are relieved of the feeling I must be doing something wrong, the steel portion is interesting. Some time back I bought a sheet of steel and it was stamped from the Netherlands, that was the only time I have seen them stamped.

[Old Iron]

I had issues with the finecut consumables and found it not worth the effort and also the loss of material to mess with it. There again, I don't cut very much artsy stuff anymore.

[djreiswig]

I must me lucky, but I cut artsy stuff with finecuts and have never really had any issues.

[Charlie10]

Indeed, Plasma Spider has been very helpful throughout the last year or so learning my way around plasma. Glad to have it and everyone's comments.

You mostly see the issues when you get toward the upper range of its capability, 11ga, 10ga.. I don't cut really any artsy stuff, but when you're putting a 1/4" slot or hole in a part you kind of need the narrower kerf. They really should be laser parts but I'm making due with plasma for the time being. It also seems like I've been able to get a little better cut quality out of finecuts, when working properly. Maybe thats just me.

[jimcolt]

I use the Finecuts on everything 10 gauge and thinner on steel and stainless. On steel...occasionally there is an issue exactly like the one pictured and described. Hypertherm process engineers think it is from a variation in steel plate chemistry, specifically carbon, silicon or manganese content. A used electrode generates higher arc voltage (a result of the electrode wear pit creating a longer higher voltage arc)….so they generally work fine....so the issue with not cutting through almost always occurs when a brand new electrode is installed in the torch....so first thought is that the new parts are defective. In my use I found that by increasing the cut height (assuming you have advanced height) from the book setting of .060" to .075" solves the problem. I do not suggest cutting slower as this will produce dross, a wider kerf and warpage. All the book specs should stay the same except for cut height increasing. After you get about 200 or so starts on that new electrode you will be able to lower back down to the .060" cut height and it will work fine. I have had Hypertherm engineers look into this a couple of times....they find nothing out of tolerance with the consumables, and can only surmise that plate chemistry is the cause. Works for me.

Note, I find that about 50% that try to use the Finecuts don't like them. They are much more finicky than any other process, but when running at book specs (with the exception of occasionally higher height) you cannot come close to matching the cut quality on steel with the other processes. Jim Colt