Hypertherm cut penetration problem

[Jcadwell]

I recently purchased an Arclight Dynamics 5x10. Works great, easy to set up, all the usual platitudes.

I'm having a problem with complete penetration at book settings.

I'm cutting 14 gauge cold rolled with 45 amp finecut consumables on a Hypermax 65.
The manual suggests 220 IPM, at 82V, at 45 amps. I believe I'm running 68 PSI as set on the plasma cutter, with 110-140 PSI running into the 4 stage filter/trap on the machine.

At those settings, pierces work great, but the cuts don't always cut completely through.

When the cut is working right, the THC works great, and maintains about .060" Z with fantastic dross free cutting.

When the cut doesn't penetrate all the way through, THC fluctuates. The parts aren't removable from the sheet, and thus wasted, and the job needs a second round to regroup and recut the parts that failed.

I can reduce cut speed to around 160IPM, which solves the penetration problem but creates others (none of the charts are useful, so I am developing all my own speeds, voltages, kerf widths, etc).

I can also increase amperage to 53 amps, and the cut looks great and is consistent. Not sure what running 45 amp consumables over the limit will do.

I have also noticed with other thicknesses that I am consistently under book speeds to make sure I get complete cuts.

Is it possible that the current measurement in the plasma cutter is not calibrated correctly?

Thanks.

[acourtjester]

If you are running the plasma with 68 PSI at the unit that is to low
go to this post and read Jim Colts info http://www.plasmaspider.com/viewtopic.p ... ge#p113640
Either your PSI is to low or the hookup hose size is to small to supply the air you need.

[Jcadwell]

I'm running above 90 PSI at the inlet to the plasma. I have the hypertherm 65 gas pressure on the display set to 68 PSI. I'm uncertain if I'm in manual or automatic mode. If manual, the Hypermax 65 regulates it to 68. If it is automatic, it is regulating itself...

I'm not getting any error messages from anything, nor does anything stop. Just isn't cutting all the way through.

[acourtjester]

I have the same setup (but DIY table) the fine cut at 45 amps does just great. I do not have the extra electronics controller that you may have so I cannot select an air pressure via the G-code. Can you change it in the Tool setting in SheetCam If so I would go up with the air setting.

[jimcolt]

There are two pressures on every plasma...1. Inlet pressure is at the air inlet. On a Powermax65 it must always be between 90 and 135 psi when air is flowing at the torch. 2. Cut pressure is the pressure that goes to the torch. On a Powermax65...it is always best to leave cut pressure in automatic mode....as this compensates for lead length, wear on the consumables and variation (to some extent) in inlet pressure.

JCadwell.....to solve your "not cutting all the way through" on 12 , 14 and 10 gauge with FineCut consumables.....run everything at "book specs"...including pierce height, pierce delay, and cut speed......BUT....increase cut height to .075" (book spec is .06") This will solve your penetration issues.

For some reason....many sheets of steel within the 14 to 10 gauge thickness range....only when cut with Finecut consumables....need to run a bit higher cut height. If you are relying on arc voltage settings for height...increase the voltage by approximately 3 to 5 volts over the book setting...or until the steady state cut height reaches .075" off the material.

I believe it is a wide variation in material chemistry....most likely different carbon, silicon or manganese content that causes this. It happens to me as well...and the increased height solves it every time.
Jim Colt Hypertherm

[Jcadwell]

Thanks for the reply Jim.

I'm running over 90 on the inlet. The compressor kicks on at about 110, and pumps up to 140. I'll regulate it down below 135 on the supply side.

I'll ensure I'm in auto pressure mode.

I'll try the higher cut height. Hopefully that solves it. I've noticed at .060" I also get a noticable taper. In a cut slot, the back of the sheet has a smaller dimension than the front. This results in a rounder edge on the front, which works nicely for art, but not for dimensional parts.

I'm new to hypertherm and have cut mostly with the finecut, and love the finish when it completely cuts. How do the standard 65A consumables compare on 14 gauge in cut quality or lifespan? I'm starting a job with about 50 sheets of 4x8 14 gauge, and would like to get this dialed, as the sheets are privacy screens. The remaining sheet is the product, not the drops. I don't want to be tossing or reworking entire sheets.

[motoguy]

Jim,

I have read where you pierce at the cut height with the finecuts. Meaning you pierce at .075, and also cut and .075. Is this still correct (above I see you recommend book height, and I believe I've also seen a recommendation of .09)? If so, does it apply to all thicknesses?

[tcaudle]

Try switching to 45 A consumables running at 45 on 14Ga. We cut miles of it. I don't use Finecut except on 16 and under and even then I make sure I use the shield made for finecut (not unshielded.) Also make sure you have the workclamp to the material to get full current flow in the cut.

[jimcolt]

You can pierce at the cut height on all materials thinner than 3/16" thickness. There will be slightly lower nozzle life....but hardly noticeable. I suggest piercing at book specs (for pierce height) on everything thicker than 3/16".

Jim,

I have read where you pierce at the cut height with the finecuts. Meaning you pierce at .075, and also cut and .075. Is this still correct (above I see you recommend book height, and I believe I've also seen a recommendation of .09)? If so, does it apply to all thicknesses?

[jimcolt]

There will always be some taper with an air plasma cutter. When you match the lowest power consumables (that the cut charts suggest you can cut) to the material....such as Finecut on materials under 10 gauge....you will get the least amount of taper. If you use the 65 amp shielded consumables on 14 gauge you can cut at incredible speeds, but expect a lot of edge taper.

You can minimize taper by locking out height control (maintain correct height but shut off arc voltage feedback control) on all holes under 1" diameter.....and on all of these holes under 1" cut at 60% of book speeds. Taper is cause by cutting too fast (on small features, especially holes) or cutting too high.

I use Fine cut on materials up to 10 gauge, I use 45 amp shielded from 16 gauge to 3/8", 65 amp shielded from 1/4" to 5/8", and 85 amp above 1/2" (I have a Powermax 85).

Jim Colt Hypertherm

Thanks for the reply Jim.

I'm running over 90 on the inlet. The compressor kicks on at about 110, and pumps up to 140. I'll regulate it down below 135 on the supply side.

I'll ensure I'm in auto pressure mode.

I'll try the higher cut height. Hopefully that solves it. I've noticed at .060" I also get a noticable taper. In a cut slot, the back of the sheet has a smaller dimension than the front. This results in a rounder edge on the front, which works nicely for art, but not for dimensional parts.

I'm new to hypertherm and have cut mostly with the finecut, and love the finish when it completely cuts. How do the standard 65A consumables compare on 14 gauge in cut quality or lifespan? I'm starting a job with about 50 sheets of 4x8 14 gauge, and would like to get this dialed, as the sheets are privacy screens. The remaining sheet is the product, not the drops. I don't want to be tossing or reworking entire sheets.

[Brand X]

I am waiting for the new low amp consumables for the 65/85/etc...Not a big fan of the fine cut stuff.. I will just us my Victor until that happens.. Partly because I can get it to do what I want,just from just using it so long.. (not picky about height, or any other setup parameter. I have a 5 minute change out between torches, and it seems to be the best of both worlds..

In fact my favorite low amp setup hands down was the 20-30 amp Esab with the PT-37 torch.. Low speed /thin metal, and plasma marking was a slam dunk every time.. 15 amp low-end was awesome for that..No fancy program to setup, other then putting in a pause to raise the cut amps after marking.. Too bad the machine was a bit scary in reliability. Could not trust after the warranty was up.. Feel real good about the Powermax there..