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Not cutting all the way through in certain areas - Swirl Ring?

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Metriccar
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Not cutting all the way through in certain areas - Swirl Ring?

Postby Metriccar » Fri Dec 18, 2015 4:39 pm

Machine Torch
Hypertherm Powermax 65
Fine cut consumables.
Plasmacam DHC2

As you can see below, it is not cutting all the way through in one area.
I turned the torch 90 degrees, and the pattern of not cutting all the way through follows it.

I took the consumables apart and pulled the swirl ring out/back in, and it still cut bad although not confined to one area.

This has been going on for a few weeks now with me.
photo.JPG

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muzza
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Re: Not cutting all the way through in certain areas

Postby muzza » Fri Dec 18, 2015 4:45 pm

My bet would still be on consumables, particularly the nozzle. You may need to look under magnification especially if it's only happening on light material at faster speeds. Try replacing each of the consumables one at a time starting with the nozzle.
Also when using finecuts the height, speed and amperage range for ideal cutting is much tighter and more critical than with standard consumables.
Murray
Last edited by muzza on Fri Dec 18, 2015 4:48 pm, edited 1 time in total.

Metriccar
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Re: Not cutting all the way through in certain areas

Postby Metriccar » Fri Dec 18, 2015 4:46 pm

Actually, after I reset the torch height and did another, it started cutting good again. But something still seems to be gong on in the body of the torch.

Metriccar
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Re: Not cutting all the way through in certain areas

Postby Metriccar » Fri Dec 18, 2015 4:46 pm

These cuts were taken after replacing the electrode/nozzle. Is it possible for the swirl ring to wear out?

bigcreek
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Re: Not cutting all the way through in certain areas

Postby bigcreek » Sat Dec 19, 2015 12:39 am

Sure the swirl ring can wear out. The swirl ring seems to last a very long time but ive definitely had them go bad before and changing it out made all the difference in the world.

jimcolt
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Re: Not cutting all the way through in certain areas

Postby jimcolt » Sat Dec 19, 2015 9:11 am

Swirl rings control the air flow to the nozzle and create the gas swirl that contributes to cut quality, concentricity and nozzle life. The swirl ring also acts as an insulator between the negative electrode and the positive nozzle. Last, but not least...the swirl ring is a slide bearing that allows the electrode to "blow back" away from the nozzle, ionizing the gas stream and firing the torch.

With more start cycles the swirl ring changes dimensionally, this change often changes the flowrate which affects cut quality. Swirl rings (on Hypertherm air plasmas) are made from Dupont Vespel because it has great dielectric characteristics, great slide bearing characteristics and can handle the temperatures as well. It does have one drawback.....it can (over time) absorb moisture and change dimensionally as a result as well.

Under laboratory conditions the swirl ring generally needs replacement after 50 or so electrode changes. This will vary with different power levels, humidity levels and duty cycles. A worn or damaged swirl ring will:

- Cause torch misfiring
-cause system error codes related to "stuck consumables"
- Cause changes in cut quality (meaning the cut will look different when torch direction changes from North, East, West and South areas of a part).

Often a worn out swirl ring will appear almost new.....it is difficult to determine when it is at the end of life. Always is a good idea to have a spare (new) swirl ring to troubleshoot the above issues

The cut quality issue posted could be swirl ring related, however I think it is height related. The cut charts say to use the Finecut consumables at a .060" cut height. Occasionally I get cuts that look like the pictured ones....and I increase the height to about .075" and the problem is solved...try a bit more height without changing anything else, I suspect it will solve the issue.

Jim Colt Hypertherm

Greg7806
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Re: Not cutting all the way through in certain areas

Postby Greg7806 » Sat Dec 19, 2015 10:23 am

im pretty new at this but mine looked similar to this,i was cutting and certain spots were doing this turned up my air pressure and it helped a lot.

sr guy
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Re: Not cutting all the way through in certain areas

Postby sr guy » Tue Dec 22, 2015 7:52 am

I had something similar. I cut HR steel. I don't believe I had a good ground, took a grinder and put the clamp on clean steel worked fine. From the picture looks like you using CR steel anyways.
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Metriccar
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Re: Not cutting all the way through in certain areas

Postby Metriccar » Thu Dec 31, 2015 8:11 pm

I replaced the swirl ring and it still had some areas it did not cut through all the way. I slowed the machine down 10% and raised the torch height to .075". So far it seems to be working.

79Bronco
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Re: Not cutting all the way through in certain areas

Postby 79Bronco » Tue Aug 15, 2017 6:17 pm

I'm currently having the same issue. Did you ever come to a final conclusion on this? Was slower and higher the answer? I've slowed mine down 15% and its still doing it. I am going to try raising cut height now.

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Re: Not cutting all the way through in certain areas

Postby motoguy » Wed Aug 16, 2017 3:10 pm

Jim suggests that increasing the cut height alone will fix it. I found the only sure-fire way to fix it was to cut at .075 as well as reduce speed 10%. A bit more dross, but much better than trying to pick cuts back up, etc.
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plasmartist
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Re: Not cutting all the way through in certain areas

Postby plasmartist » Wed Aug 16, 2017 3:53 pm

I cut with finecut every day using my pmx85. I just recently switched from aftermarket to genuine cons and noticed a huge difference for the worse, but got it figured out so I'll explain my findings and hopefully you or someone else can benefit from them. First off, my aftermarkets were cutting ok, but just not lasting long enough so I made the switch to genuine. Most of this is going to be straight forward, but hopefully something helps.

First notes: (these observations were all made on 10 ga mild steel)
-genuine finecut cons are very particular about air pressure and adequate cfm. I was running 3 dryers 6 feet out of the compressor with a regulator set at 120psi, then had a small inline desiccant at the end of the hose to catch the last moisture before the entry to the pmx. This cut fine with the aftermarkets; However with the genuine I got the air warning code, and it was having a lot of issue penetrating. to the point I switched back to aftermarkets (at least for that project).
-genuice finecut cons do like cutting between .06-.08" at 95 ipm at roughly 84 volts in my case (I run full speed all the time). The aftermarkets I was using performed much better at about .02-.03" at 95 ipm at roughly 78-80 volts.

So why am I telling you about this? Because when I made my consumables brand switch I was having the same results as you are describing. And here's the way I fixed it. I set up a straight line test and changed all the of the values in sheetcam to the recommended settings in the manual. Low and behold the recommended settings in my case were the best.
-pierce at .15' (make sure your z is deadly accurate, as well as your limit switch offset) What I mean is follow the same steps you did setting up your x and y axis to make sure you have the correct steps per unit. For some reason my tool set was originally set to pierce at .08", but I noticed slag getting on the shield and nozzle when piercing, so changed it to .15".
-cut height at .06"- I still haven't messed around with the .08 setting, but will probably do some experimenting with .07. This setting only matters for the first second or so (depending on your settings).
-volts set at 84, with my dthc set at 84 volts the dro shows the height at roughly .07", and its cutting like a beast.
-make sure you are using all the correct consumables, INCLUDING THE 220953 RETAINING CAP. when I first changed to fine cut I didn't use the correct retaining cap and the torch volts were drastically different from the manuals (can't remember which direction as it was a while back). I tuned for it, but ultimately switched to the correct retaining cap.
-use a pierce delay in accordance with the manual. The toolset offered by candcnc didnt have a delay, but I found better cuts using about .15 second delay on 10 ga (manual recommends .5 seconds)
-lastly, and not to question anyone's intelligence, but use the correct amperage. I have played around with increasing amperage, but there is a reason for 45 amps, although I have found that I can raise the amps on an old nozzle to finish a project if need be.


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