PowerMax 65 machine torch issue - air escaping retaining cap

[B Holmes]

I am trying to diagnose some cutting issues with a PM65 machine torch and fine cut consumables.
I have been experiencing some varying angularity and inconsistent cut quality on some 10 and 12 gauge hot roll mild steel. I have changed to new consumables, new swirl ring and a new o ring. All parts are genuine Hypertherm. Air pressure at the back of the power max is consistent at 120 psi. While cutting I have noticed some air pressure coming out at the top of the retaining cap. I have tried different retaining caps and the air continues to come out above them. Is this normal?

[acourtjester]

I would say that is not normal, you said you changed the "O" ring did you use any silicone grease to lube the assembly. If not you could have damaged the new one and still have a problem with incorrect air flow.
Hypertherm number for the grease is 027055.

[B Holmes]

Acourtjester,
Yes I did lube the o ring with silicone grease. I even put a second o ring on just to try and had the same results.
I will call Hypertherm Monday to verify that air should not be escaping above the retaining cap.
Thanks for the reply.

[acourtjester]

Please leave follow ups for others who may run up with this later

[B Holmes]

Will do.

[TJS]

So am I reading this correctly. You are cutting 10and 12 gauge with fine cut consumables. Why?

[B Holmes]

So am I reading this correctly. You are cutting 10and 12 gauge with fine cut consumables. Why?

Good question. I have just always used fine cut for these thicknesses as I am looking for the best shape and angularity quality that I can get.
I typically am making mechanical components that frequently bolt together using small carriage bolts ( 1/4" or 5/16"). So I am cutting small square holes and need the best definition to achieve the squarest inside corners that I can.
I have just assumed fine cut would give me the best quality. Now that you bring up WHY?, you have me running some tests. I have completed the 10 gauge tests and to my surprise, 45 amp shielded works just as well as I used to get with fine cut and has the benefit of being shielded. 12 gauge might be a little harder for my table to do with the higher cut speeds, we will find out.
Thank You TJS for making me look at this from a different perspective.

[TJS]

I am very new to this. I cut a lot of 14ga and do not use fine cut consumables. I just use the 45 amp consumables. I think the hypertherm manuals state to use fine cut starting at 16ga. and thinner. I am sure someone will correct me here.

[robertspark]

https://www.hypertherm.com/Download?fil ... &zip=False

65 operator manual ^^^, pdf page 85 VVVV

2020-01-14 21_36_46-Window.png (113.98 KiB) Viewed 1217 times

2020-01-14 21_36_46-Window.png (113.98 KiB) Viewed 1217 times

[B Holmes]

To continue the original discussion about air flow coming out at the top of the retaining cap, it appears as though it is designed for that. I took my torch apart and there are three slotted holes just above where the retaining cap stops that are open to the cavity where the compressed air is traveling towards the nozzle. Although I have yet to confirm this with Hypertherm, I have verified that my hand held torch also does it.
I still don't have any answers why I can't get my fine cut results anywhere near where they used to be. I am starting to wonder if it is the material itself.

[robertspark]

What swirl ring do you have in the torch for fine cut?

Can you take a photo... It should have less holes in it

Where are your angularly issues ? Corners, arcs or holes (best to slow down for these to allow the tail to catch up ) Only on one axis or direction (is the torch square to the work)

[djreiswig]

I was unaware of a different swirl ring for finecuts. I use the same one for everything.
I found this post where Jim Colt explains the difference.
https://weldingweb.com/showthread.php?7 ... onsumables

[robertspark]

Interesting post, I unfortunately don't have fine cut consumables using a 45 non xp with a standard torch ..... I've just seen both listed in the various manuals for the 45xp, 65 and 85 ... I keep toying with getting a duramax machine torch but cannot commit to it

Saw less holes in it and given the orifice is smaller on the nozzle of a fine cut I presumed that the fine-cut swirl ring therefore would have acted as a volume control device providing more restriction upstream which is calibrated to the nozzle hole orifice size thereby trying to ensure that the tight swirl pattern is maintained as would not be the case with s swirling with more holes in it which would have less of a restriction, less of a pressure drop and less control over the swirl pattern given more air pressure would be placed upon the electrode .... Thereby potentially blowing it back slightly more leading to a wider gap as the voltage would need to be higher given the electrode was slightly further away for the machine to maintain the same amperage (as a plasma machine is a constant current source)

Guess I was maybe just overthinking it why one swirl ring may have more holes and a nozzle with a bigger orifice and the other nozzle a smaller orifice and swirl ring with less holes.

[jimcolt]

Sorry I have not responded on a timely basis to this post. Yes, cooling air does escape from all Hypertherm torches above the retaining cap....it is additional cooling for the internal mass off the torch and is necessary and normal. Finecut consumables are designed for 10 gauge and thinner cutting of steel and stainless. They will provide a narrower cut kerf (about .006" to .010" narrower) along with slightly squarer edges as compared to the 45 amp shielded consumables. You can use the same swirl ring for the shielded and the Fine cut consumables.....though there is a special Finecut swirl ring that was developed for hand cutting. Some use this on machine applications, though I see no need to.

Finecut consumables are far more finicky in regards to metal chemistry , cut height and cut speed. If you machine cannot maintain very accurate cut height and slows too much on intricate details....then Finecut may not be your best choice. Jim Colt

To continue the original discussion about air flow coming out at the top of the retaining cap, it appears as though it is designed for that. I took my torch apart and there are three slotted holes just above where the retaining cap stops that are open to the cavity where the compressed air is traveling towards the nozzle. Although I have yet to confirm this with Hypertherm, I have verified that my hand held torch also does it.
I still don't have any answers why I can't get my fine cut results anywhere near where they used to be. I am starting to wonder if it is the material itself.