Trouble cutting 3/8” with Crossfire Pro and Primeweld Cut60 (Not solved yet)

CrossFire ® PRO
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Hello,

I just attempted my second cut(s) on some 3/8” plate on my newly assembled Crossfire Pro, running Primeweld’s Cut60 plasma cutter and their machine torch. I only had one piece of metal, so I would tweak settings and repeat the cut, and I did this a few times, and never really got through the 3/8” plate cleanly all the way around. I’m not sure how much help my pictures are going to be, given that I took multiple whacks at it with different settings, but I’ll do my best to explain my process, and hopefully I can get some recommendations on where to start improving.

My air system is a 5hp (overrated) 60 gallon upright compressor, into a 40 micron pre-filter, followed by 50’ of 3/4” max air line, into a 3 stage Motorguard progressive coalescing filter/desiccant dryer combination. I have no discernible moisture. I also live in the desert, so it’s pretty dry to start with.

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1st cut settings:
1.5 second pierce delay
0.150” pierce height
0.060” cut height
40 IPM
53 Amps
70 Psi
Ground connected to table drain but (per Langmuir’s recommendation)

1st cut was really clean in a couple of spots, and didn’t cut through at all in several others. Holes appeared somewhat tapered.

Video of first failed cut.

2nd cut settings:
Dropped feed rate to 37 IPM
Bumped amps to 55
Bumped air to 75 psi

2nd cut wasn’t really any better than the first. Checked consumables after (were new prior to the first cut) and they were toast, so I replaced them. I also tightened the coupler on my z-axis, which I suspect was slipping.

3rd cut settings:
2.0 second pierce delay
0.150” pierce height
0.060” cut height
35 IPM
55 Amps
75 Psi
Ground still connected to drain nut

3rd cut results finally started to work at the area’s on the perimeter that didn’t seem like they were cutting at all the first two times, but still didn’t get through them.

4th cut settings:
Moved ground to work piece, just ran perimeter. Still didn’t get all the way through. Gave up. Checked second set of consumables and they were toast now too.

Anybody have any thoughts? I hope to work a LOT in 3/8” steel with this machine, so I hope it’s going to be up to the task, but the learning curve is looking like it’s going to be darn expensive.

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Your cut speed seems a bit fast for 3/8" material. I cut 1/4" steel at 45 amps and 22ipm. I’m guessing you’d get better results in the mid 20iom range.

My experience with re-cutting over a section that failed to cut thru have never been good. It just doesn’t cut the same after it’s been hardened by the first attempt.

What size nozzle are you using in the torch. 55 amps should need at least a 1.1mm nozzle. A smaller nozzle will burn up very quickly at that power.

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The only nozzles that came with my Primeweld are 1.1’s. I’m not sure if they offer another size, or not.

That’s good to know about the failed cut being harder to get through; I had wondered about that. I chose 40 because my Primeweld’s cut chart lists 43.31 IPM for 0.333” material, and 39.37 IPM for 0.400” material. They do suggest that 0.500” material steps down to 23.62 IPM, but I agree slowing it down seemed to do better on subsequent cuts.

Also, I just added a link to a video of the first cut, back in the previous post.

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Air should be 120 to the back of the plasma cutter and 75 flow from the torch should be fine. Work clamp always goes on the metal not the table. Turn the THC off you don’t need it on 3/8". Make sure you are really cutting at .060".

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First thing I thought, wonder why he was told otherwise?

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George,

I was just reading your post about consumables for Tecmo PTM-60 torches, which is supposedly what I have; Primeweld says it is a legit Tecmo, made in Italy.

I don’t mean to question you, because I know you are a guru, but here’s what I can speak to:

Primeweld’s books said not to have any more inlet pressure than 90psi, and no more flow than 75psi, so that’s where I set it. FWIW, 75psi was set flowing, and my compressor never kicked on during the cut.

The ground was hooked were Langmuir recommended, BUT, I agree it did better clamped on the workpiece, and should definitely be there during cutting operations.

This particular piece of 3/8” plate had enough warp in it, that I couldn’t dial in a 0.060” cut height. I get that the THC could be a variable, but shouldn’t it be able to work if set up properly? I’m not entirely certain it is working properly, but it has passed all of Firecontrol’s health checks.

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All I can say is I have about 40 grand of Tecmo consumables in stock and NONE of them have metric size on them.

If your not cutting through 3/8" at 55 amps your not cutting at .060"

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It was in the instructions at least once that I saw…

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Wow I would have never guessed that. Wonder if they still recommend that?

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Alright. Sounds like maybe the $300 Tecmo machine torch I bought is a knock-off, and maybe my THC isn’t working. I assumed that the software would throw an error if the THC was malfunctioning. I guess I need to go back and re-read that troubleshooting guide.

Thanks for the info. So, any thoughts as to why I’m blowing through consumables so quickly? Is it just because they’re cheap Chinese crap? Also, any thoughts on the 40 IPM speed? Is that part of my problem, anyway?

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From the pictures when it cuts it cuts clean. That tells me your cut height is to high. Your setting other wise should work.

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I don’t know if you watched the video, but I just zoomed in and slowed it down, and you can see that the THC is pulling the torch up everywhere that it didn’t cut clean. Not sure why it’s pulling the torch up randomly, or how to fix it, but that seems to be my issue.

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If your using smart voltage that may be causing it.

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It is, but only because this was literally only the second cut I’ve made, and my first plasma cutter (CNC or otherwise). I’m basically set to all of the defaults, with feeds and speeds based on Primeweld’s cut chart. I want to say that the voltage was set around 105V on this cut. The first screw up was immediately after a pierce, and the second one was in the middle of a corner, where my stupid silicone shroud got caught on the plate. Gosh, I almost think I should just get another piece of 3/8” and run the cut again.

I need to find out where to get consumables for my Chitalian torch…I sure hope they last longer than 1 cut once I eliminate my issues, or I’m not going to be able to afford this hobby. :roll_eyes:

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I have a Primeweld cutter as well.

I haven’t cut any 3/8” I have cut 1/2” I don’t remember the settings I used but I will look it up. I think I pretty much used the book settings. I found some scrap at our local supplier and cut 2 inch squares with a 1 inch hole as a test. It is expensive material to test on but I don’t think you can dial it in without a little testing.

Two reasons I can see for the short consumable life.

1: over cutting a previously cut path.
2: cut heigh to high

Try to find yourself some scrap and do a little testing. You could cut the squares out of the piece you already cut.

I am confident you can get this dialed in. You may have to plan ahead on duty cycle but you can do it.

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Your pierce delay is too long, and like George said turn off THC. You want 110-120 air pressure from air compressor too back of plasma machine and set air pressure torch 70-75. Turn machine amps up to 60 and make test cuts on same material you have been cutting on, install new consumables first before trying. pierce delay 0.6 second.

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you need to be careful when talking about pressure and flow…there is a big difference…
The difference between PSI and CFM is what they measure. PSI measures pressure, while CFM measures volume . PSI and CFM are performance specifications for air compressors and air-powered machinery. Together, they indicate the maximum air volume and pressure produced by an air compressor to power air tools.
also…if you are reducing air flow with 1/4" couplings you are reducing flow and increasing a false pressure reading…
here is a great little bit on air flow vs. pressure…

you may be keeping the pressure steady…but your flow needed may be off…

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Do you use a Primeweld machine? I’ve seen the 110-120 number for other manufacturers, but have heard of high pressures causing internal leaks on the cheaper machines, and warranties not being honored because it was obvious too high a pressure was used. As I mentioned above, this machine’s instructions say to never exceed 90psi inlet pressure. Is there a reason pressure at the back of the machine needs to be so high when the “flowing” pressure maintains the 70-75 psi it is set to? I have 60 gallons of storage, and 50 feet of 3/4” line that are all at 130 psi ahead of the regulator turned down to 90psi going right into the back of this machine…

I tried turning off THC and the tip crashed into the plate. This particular piece of 3/8” has some warp in it, but I DO think the THC might be part of my issue.

I was also told to run a minimum of .8 second pierce on this machine in particular (by multiple owners), and to go up from that number for thicker material. My first cut was .5 seconds delay on 22 ga, and it didn’t even touch the metal for the first 3/4” of the cut…

Anyway, I’m not trying to discount your advice. I just wonder if you’re speaking from using the same equipment, as it sounds like my particular equipment might have some limitations.

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My mistake. I was trying to articulate that the 70-75 psi I had set was a “pressure” number that I obtained with the air “flowing”.

The entire air system to the plasma cutter is plumbed with 1/2” NPT fittings, with the exception of a single “high flow” 1/4” NPT fitting and coupler at the back of the actual machine. The high flow style fittings, as I’m sure you are aware, have the 3/8” fitting body style with 1/4” NPT threads. They are from Milton, and I want to say they are rated to flow at about 67 cfm each.

I do believe that the 3 stage filter/dryer setup takes a huge bite out of the CFM of the system, however I was told be several people on this forum that it was an absolute necessity, despite Jim Colt’s post on Plasma Spider saying that he would rather see CFM than perfectly dry air, at the back of a plasma machine. I believe the consensus was that Jim wants to sell consumables.

FWIW, I really did my best to “do my research” prior to setting this thing up, because I need the machine to start paying me back ASAP.

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Erik,

If you can find me those settings it would be very helpful. If you’re right out of the book, then I’m going to be a bit worried, because I was also right out of the book on this, and it was pretty bad.

The more I read these suggestions, the more I realize I have to throw out everything after the first cut, because the recutting created a ton of problems and twice as many variables.

The book suggested that 40 IPM starting point for 3/8” (by extrapolating from the suggestions for 0.333” and 0.400”), but I think it’s just too high. They do recommend dropping all the way down to 23 IPM for 1/2”…I’m curious to know if you wound up running it slower. I’m thinking I need to drop to at least 30 IPM for 3/8”, and kind of feel like everything else would have been fine on that first cut, especially if I had had the ground on the actual workpiece, and hadn’t been messing around with that stupid Chinese funnel on the end of my torch (which is maybe a Chinese knock off itself :rofl:).

Thanks!

Oh, and I’m going to try some little brackets in the space on the corners of this plate, and try a few of these suggestions, and see if I can actually get something to cut clean. The only other thing that it could be is the THC, and if it isn’t then it sounds like I am one of the dreaded few who might be dealing with some kind of interference…even though I’ve really tried to eliminate all of those variables too. :flushed: