1/4" MS Cut w/ 45A Shielded - What am I doing wrong?

[pupdogg]

I normally cut thin gauge material (16-14GA) on a PM125 using FineCut consumables and everything works great! However, we recently got a 1/4" job and I figured prior to cutting the actual customer plate, I dial in the settings so that there are no surprises or destruction of customer material. So, I gave the Initial Cut Test (from CandCNC) a shot on a 4in wide 1/4" flat bar stock. These are basically, 4x 16" long lines 1" apart that are 1) cut with book settings and DTHC off and 2) based on the avg. recorded arc voltage, dialed in and cut with DTHC settings ON.

Here's my setup:
- Hypertherm PowerMax 125
- Brand new 45A Shielded Consumables - GENUINE!!! (420168 shield, 420156 ohmic retaining cap, 420158 nozzle, 220997 swirl ring, 220971 electrode)
- Bulltear 5x10 CNC Table with CandCNC Servos
- CommandCNC Software
- Air via Atlas Copco GX11FF 15HP Rotary Screw Compressor with integrated dryer
- New o-ring with Hypertherm supplied silicone on the torch
- Cutting at book settings (0.064 KERF, 0.6s PD, 0.15 PH, 0.06 CH, 45A, 43IPM, 132V)
- The ground is connected directly to the part being cut

Here's my issue:
1. There seems to be extensive dross right at the start of each cut (1st and 2nd pic below)
2. Even though the cut looks great from the top, it doesn't seem to be cutting all the way through (see the 3 pic)
3. After examining the cuts with DTHC off, I get an average voltage of 123V. However, when I try to cut with DTHC ON and that voltage with sensitive set to slow, the torch either keeps plunging after 15-20 secs of normal cut or hitting/falling off from the dross caused at the start of other cuts.
4. Since the flat bar is sitting on 2x 2x2 square tubes so that I can eliminate additional noise cause by water, I am able to see the cut arc and it seems to be trailing the torch, not leading...I know it's supposed to be leading...what could cause that? There are not sparks above the material...they are all below the material and the torch does look and sound good when cutting. I say that because at this point, it is very easy for me to spot whenever the torch is cutting too higher as I get a lot of sparks above the material and next to no cut/all dross inside the cut path.

PLEASE HELP! - What can I do to fix my issue. I think I've tried to cover all of details about my settings here. It's very perplexing especially when all the consumables are genuine and brand new.

Image #1


Image #2


Image #3


Image #4 - Torch O-ring - that black stuff is grease

[motoguy]

Low air pressure? That could explain the non-evacuated dross at pierce, as well as not "punching" all the way through. I know mine look kinda like than when forget to turn the compressor on, and it's just using the air stored in the lines for a few seconds...

[jimcolt]

I agree that the issue is pressure related.

- replace the o-ring on your torch as a starting point and clean the torch well.
-If you have not tried a new retaining cap...this can cause this issue.
- With air flowing at the torch check the inlet pressure....with a gauge hard plumbed right on the inlet. Compare this flowing pressure to the pressure back at the source. You will see it is lower at the inlet. Any chance that when the compressor is at the bottom of its cycle (lowest pressure) that the inlet may be getting below 90 psi?
- Carefully inspect the torch leads for cracks, leaks. Maybe disassemble the torch and look for air leaks on the service connection for air.
-Do you hear any leaks inside the plasma cutter? Check the auto drain on the moisture separator and listen carefully by the solenoid air valve (this is a dump valve.....on occasion they leak if there is any debris getting through the air system.)

Last but not least. Hypertherm tech service is the best source for help. technical.service@hypertherm.com or 1 800 643 9878

Jim Colt Hypertherm

[pupdogg]

Thanks guys, I will verify the air pressure today. Below you will find some detailed images of the filter element, the consumables and the torch assembly...please let me know if anything raises red flags to you. Thanks!

Filter Element


Consumables 1/2


Consumables 2/2


Torch Assembly 1/6


Torch Assembly 2/6


Torch Assembly 3/6


Torch Assembly 4/6


Torch Assembly 5/6


Torch Assembly 6/6

[WyoGreen]

To me it looks like the nozzle in your consumables 1of2 picture has a notch out of the round hole. Might just be the angle of the picture, but if it does and it is new like you said, then something is not right. (no idea right now what that may be)

Steve

[pupdogg]

Ok, was finally able to cut some 5/16" test material as I ran out of the 1/4" stock. Noticed a significant improvement after changing out the nozzle. Apparently, the other new nozzle was damaged within the first 2 test cuts...not sure how...but luckily, I got the 25pk and was able to swap it out for a new one. Below are a few pictures of the cut part. This was all at book settings. I don't see much of a taper on the edges. It just that I'm still getting dross on top of all cuts (which I can easily knock off with a scraper) and if you look at the small line cuts, them seem closed-off...both of these issues are happening right at the start of the cut...looks like from piercing. Any advice?

[tasibrett]

Looks like when i forget to crank the amps back up after running the FineCut consumables

Brett

[pupdogg]

Hi Brett,

Sorry actually I forgot to mention that since the max thickness 45A nozzle goes to is 1/4" (I know I could've pushed its limits) I used 65A nozzle for this cut. I was sure to crank those amps up to 65A as well...the book settings stated 130V bit based off of my DTHC calibrated arc volts, I ran this cut as 113V.

[tnbndr]

Are the small cuts being made first and then a perimeter cut? It looks like the perimeter cut may be what is closing off the small cut. I would play with cut speed, try a little faster and see what happens.

[jimcolt]

If you have the mode switch in the gouging mode or the expanded metal mode it could give these symptoms as the air pressure is lower in each mode as compared to the cutting mode. The nozzle picture is clearly junk....the orifice needs to be perfectly round. The notching is caused by piercing too close to the material.

Jim Colt Hypertherm

[steel 35]

Arc ok jumpered?

[pupdogg]

@tnbndr: thx for the tip, I will try it out tomm.

@jimcolt: no the gouging mode isn't on...it's on standard mechanized cutting mode...I believe the 2nd knob option...just got some new nozzles in today and will give this a try tomm.

@steel35: no, Arc OK is not jumpered