Strange Noise from Hypertherm causing serrated cut

[adventureleven]

Hello all. I know sometime plasmas will whistle whine or humm a bit but this one is new and strange. I am running a Hypertherm 1650 on a Samson 510 with plasmacam software. We cut a lot of material and have been running this set-up for over 2 years. I am cutting 3/16 steel P&O.
The plasma is now making a vibrating noise. You CAN'T feel it in the table our material like a bad bearing or worn parts, it is like the plasma is spitting, kinda like playing the tuba. Went through all the normal of changing consumables but the cut is actually very straight all the way around the part.

Problem: the noise is directly related to a fine serrated cut. If you hear the noise you get a serrated cut, no noise smooth clean cut. The serrated cut looks like a laser when it is worn out not like a plasma when it is worn out. This is much finer than a plasma rough cut due to worn table parts.

[WSS]

Did you change the swirl ring? We have a 1650 and when it whistles it is time for either a swirly or a swirly holder. Usually the cap gets tightened too much too many times and squeezes the swirly and causes the electrode to stick some and the air coming out is no longer swirling correctly.

JMHO!

Good luck,
WSS

[adventureleven]

Yup, changed all consumables twice just to make sure. I did blow out the plasma machine and it had a strong electrical odor, then it seemed to work better for a little while. I have a feeling the Hypertherm is having an issue internally.
Thanks

any other ideas? I will try and get a Hypertherm rep out to look at it.

[adventureleven]

one more thing....The dross is also increased and generally we have very little to none. I made many large changes to settings just to see if I could make it go away and the noise stayed the same and cut quality just got worse.

[jimcolt]

Serrated cuts are usually causes by one of the following:

1. Roughness in the x, y or z axis motion. If you put your hand on the torch body while it is cutting and you feel any vibration or oscillation.....expect it to show clearly on the cut edge.

2. Incorrect cut speed....try slightly faster and slightly slower and see if you notice the serrations change.

3. Slat bed vibration.....or the materials itself moving or oscillating. Put your hand on the plate or sheet while cutting to stop any possible movement...then observe the cut edge.

4. Moisture in your air line will cause edge roughness.

5. Incorrect air pressure to the torch....refer to the manual for proper air pressure setting.

6. Worn or damaged nozzle, electrode, swirl ring or retaining cap.

7. Worn or missing torch oring.

8. Leaking or restricted torch or torch leads.

9. Damaged torch.

10. Plugged or leaking inlet filter assembly.

All of the above will cause the arc to make a sputtering sound.

[adventureleven]

Thanks for the info.
I have a torch coming today from my welding supplier for me to try.

I have got a rough cut from the torch moving before and this is very different. When the problem occurs i can put my hand on the torch and material and I do not feel anything. FYI, I just re-bearing and new rack and pinion gears about 2 weeks ago. This is a much sharper and finer serration than when the torch moves or material moves. It takes about 30 minutes or more of cutting for it to get good and warmed up before the problem starts.

[jimcolt]

It is rare that the torch will cause this issue....but can certainly happen. The air flow is the single most citical parameter with any plasma system. A small piece of dirt or debris lodged in the torch or leads .....a loose fitting, a cracked or split hose or fitting will disrupt the cut quality. I assume you have tried a new retaining cap, swirl ring....and have checked the oring on the torch. Also a good idea to take the torch apart and look for leaks...loose hose fitting, etc.

Keep us posted on what you find.


Jim Colt Hypertherm

[adventureleven]

In the meantime I had parts that the cut quality was not that big of a deal so I continued to cut parts. The cut quality rapidly went south until it was beveling in all directions and just really poor along with the strange noise even though the serration kind of went away. My welding supplier loaned me a old used T-100 torch, I put it on the machine and PRESTO! No noise, perfect cut and the machine even sounded nice and crisp. The torch is my second torch on the machine, the first torch lasted 1 year and 2 months then Hyperthem warrantied it (even though it was 2 months out of warranty!!). This torch is 1 year and 2 months old also so my welding rep is going to contact Hypertherm in the morning.

I have a feeling the issue is with holding the torch in the same position with the cord bending back up and around from the machine. It basically gets baked in this position and I think it causes it to fail. I dont think hand torches are really made to be used this way. I am going to look into a machine torch.

[jimcolt]

The hand torch is made for hand cutting! Machine torches are for machine cutting...the lead package can handle more flexing and the mounting methode is far more robust.

Jim Colt Hypertherm