star labs plasma table not cutting virtical

[scarymonkeyman]

so we are cutting through some 1/2 416SS and recently it started cutting crooked as shown in the picture. Tried swapping out the electrode, nozzle and shield and no difference. bumped the feedrate override to 80% then 120% no change. 85amp 132volts feedrate at 15. as its running actual volts are 140-143

 

[DDoug]

"This member limits who may view their full profile."
Why have you done this ?
what is your location ?

 

[scarymonkeyman]

"This member limits who may view their full profile."
Why have you done this ?
what is your location ?

didnt realize it was hidden, location shouldnt really matter

 

[DDoug]

didnt realize it was hidden, location shouldnt really matter

It does if your in a far off land, where materials & machinery are scarce.
That pix doesn't show much, take some better pictures.

 

[scarymonkeyman]

is this one better?

 

[RC Mech]

Given the information, I’d wager the head got bumped out of alignment.

 

[dana gear]

What your cutting is a excessive positive angle, If I understand your post everything was operating as it should and it out of the blue started cutting a positive bevel. If that's the case then it's most likely a process problem, go back and recheck everything!!!!,In your picture your plasma torch would appear to be vertical to the material being cut. You may want to change out the consumables and retry, I cannot tell you why but more then once a new components have have played games .
Excessive positive angle is generally caused by inadequate amperage for the material being cut, travel speed can also be a factor, high stand off voltage could also be a problem. 1/2" S.S shoot for around 146 volts, your running 85 Amps so travel speed will be in the somewhere in the 23-35 ipm, note this is just a basic starting point, and not carved in stone.

 

[scarymonkeyman]

Dana, we have run a few 4'x8' sheets before running into this issue. I'm going to guess the tip height affecting voltage could in turn lower the amp?

raised the height up over the 0.6 that is recommended and it raised the voltage to 150 and it got a couple straight cuts before going back to the angle. i will check tomorrow to see if the height lowered tomorrow when things cool down. If it didnt change i will try another nozzle and electrode. could the air blast have anything to do with it cutting like it is? My coworker is curious if the start point on the edge can change it, or possibly running it on the other axis?

 

[memphisjed]

Your cut looks like a out of tram torch.
Your water level is too high- by a considerable amount - drop it down 2” or so.
Lower running thc volts by 6.

 

[BT Fabrication]

are the sheets magnetized?

 

[DrHook]

Your cut looks like a out of tram torch.
Your water level is too high- by a considerable amount - drop it down 2” or so.
Lower running thc volts by 6.

I'm not a plasma operator, but I am wondering why the water level would affect it, as the last place I worked has a plasma table which cuts under the water. Maybe just the camera angle on that shot, but we never let our water get so cruddy it looked like prison soup. If I remember correctly, an angled kerf was usually due to excessive cutting speed, once the consumables were proven to be good.

 

[memphisjed]

I'm not a plasma operator, but I am wondering why the water level would affect it, as the last place I worked has a plasma table which cuts under the water. Maybe just the camera angle on that shot, but we never let our water get so cruddy it looked like prison soup. If I remember correctly, an angled kerf was usually due to excessive cutting speed, once the consumables were proven to be good.

Underwater is for thin gauge only, hypertherm’s colt says 6 inches below surface, I find that to be to Smokey, 3 to 4 inches works well. If a few drops come up behind the cut but plate surface is dry seems to be sweet spot. Changing out water is expensive, so you try and get a good five years out of it on industrial tables. You have to use haz mat vac truck haul it away.

 

[DrHook]

Underwater is for thin gauge only, hypertherm’s colt says 6 inches below surface, I find that to be to Smokey, 3 to 4 inches works well. If a few drops come up behind the cut but plate surface is dry seems to be sweet spot. Changing out water is expensive, so you try and get a good five years out of it on industrial tables. You have to use haz mat vac truck haul it away.

I believe the one we had was an ESAB, and I do not recall the amperage, but we cut up to 1-1/4" plate steel with the water at the top of the plate. The torch had an "air blast" which pushed the water away from the head about 4-6 inches around the head before the arc started, but the parts thin and thick were all under water for the cut. A lot less smoke, which we could prove by running it without triggering the "fill" sequence. Our tank was deep, and the crud flowed to the lower level when the water level lowered, so maybe that helped keep it looking cleaner...

 

[DDoug]

Underwater is for thin gauge only, hypertherm’s colt says 6 inches below surface, I find that to be to Smokey, 3 to 4 inches works well. If a few drops come up behind the cut but plate surface is dry seems to be sweet spot. Changing out water is expensive, so you try and get a good five years out of it on industrial tables. You have to use haz mat vac truck haul it away.

I have been cutting up to 1/2" with a Hypertherm 65 amp machine on a small table.

I've got to get the water to within 1/2"-3/4" up under the plate to capture smoke & steam.
it splashes up just enough to keep the part cool as well. Not a severe quench that causes tenacious slag to adhere to the part.

I have not used it for 8 weeks and the table is bone dry, need to scrape out the slag & sludge.

Should be cheaper to dispose of dried sludge ?

 

[memphisjed]

Should be cheaper to dispose of dried sludge ?

We let ours get low, as low as what is retained in the bubble chamber (not sure the technical name). This is because vac truck charges by volume. The tray sludge goes in scrap bin, the sludge in the lower section and bubble gets vac tricked away.

The severe quench is what got me searching for expert water level advice. I do not have to deslag most of the time (fitter/welder job) but warpage (plate thickness, not gauge thickness) is higher with high water. Sounds backwards, but the metal can dissipate heat relieving the heat expansion force.
Metal working takes to much brain working.

 

[dana gear]

What your cutting is a excessive positive angle, If I understand your post everything was operating as it should and it out of the blue started cutting a positive bevel. If that's the case then it's most likely a process problem, go back and recheck everything!!!!,In your picture your plasma torch would appear to be vertical to the material being cut. You may want to change out the consumables and retry, I cannot tell you why but more then once a new components have have played games .
Excessive positive angle is generally caused by inadequate amperage for the material being cut, travel speed can also be a factor, high stand off voltage could also be a problem. 1/2" S.S shoot for around 146 volts, your running 85 Amps so travel speed will be in the somewhere in the 23-35 ipm, note this is just a basic starting point, and not carved in stone.

O.K. something to look at, high torch stand off will cause the arc to lag which causes more energy to contact the top of the material being cut then the bottom. The kerf will be somewhat wider at the top and narrow the bottom generally caused by a worn nozzle and as I stated above ,inadequate amperage and or excessive travel speed. Your particular water table has noting to do with your cut quality. That type of plasma generator are you using? As as I said before recheck all your process.
With plasma it does not take much out of correct parameters for things to go bad. I am assuming you have THC on your controller, just for giggles watch your voltage during the cut process, if you see much voltage change, try running without the THC activated.

 

[scarymonkeyman]

so update: Went on plasma spider for advice and someone mentioned looking at the o-rings and when replacing the nozzle, shield, swirl ring, and retaining cap with name brand parts saw the one o ring was extra minty and 8 cuts in it is staying vertical. Once we have time to play around i will try and see if the knock off still works or not. here is the link to the thread

Hypertherm 85 amp cutting at an angle - PlasmaSpider.com

Hypertherm 85 amp cutting at an angle

www.plasmaspider.com

 

[dana gear]

WOW, theres a surprise, In my first post I told you to change out all consumables, and retry. And with Hypertherm NEVER use knock offs.

 

[Strostkovy]

I'm late to the thread but we've had our hypertherm plasma torch cut badly on two occasions despite consumables being new. The solution both times was disassembling and cleaning the head.

We had a shallow table and always cut with the water up to the sheet to minimize smoke and heat. It won't affect your cut except in very specific cases.

Paying for a vac truck seems odd to me. We just shoveled out the junk into bins and let them dry and threw out the dusty gunk. The water left behind is brown but just fine.