What low amp/non book setting do you use for thin material?

[motoguy]

I've recently started cutting more 16 and 18ga steel, as well as picking up some .063 AL sheet. I'm using Sheetcam rules to shut off the THC, and not slowing down on corners and arcs. It cuts quite well. It still gives the impression of using a fire hose to wash the dishes, though.

My PM85 has a 25a minimum setting. I know I've seen people mention below-book amperages for finer detail, slower speeds, etc. Those of you having success, would you mind sharing your low-amp settings for thin material? Amps, volts, ipm? Cut quality and detail would be my priorities

I'm happy with the amount of detail I can achieve with the finecut tips, but if I can improve on that, I'd be even more excited.

[jimcolt]

As I've stated many times.....using lower amperage on a nozzle that is rated for a particular amperage (such as using finecut consumables with a 45 amp rating at 25 amps) reduces the energy density of the arc. Reducing the energy density decreases what we call the "Dross Free Interval", which is a speed range between cutting too slow (low speed dross) and cutting too fast (high speed dross). A well designed set of consumables will have a rather wide speed range where it cuts a particular material and thickness range essentially dross free. Using this same set of consumables at lower amperage will decrease that speed rang....or eliminate it. Dross is the result, though often it produces dross that is easy to remove (chips easily, falls off when you drop the part on a concrete floor, etc.!)

Hypertherm publishes a set of cut charts for Finecut use that are called "Finecut Low speed) that work acceptably with the cut speeds limited to under 150 ipm. I use them on occasion when cutting parts with more detail, though the kerf width is wider, the lower speed makes many machines have more stable motion.

So, the next natural thought is that Hypertherm's process engineers should simply make a 25 amp nozzle (or a 10 amp for the Powermax45XP) that still maintains the energy density of the larger nozzles, right? Well we have been working on that ability for years.......and have had as low as 15 amp nozzles that we used with our High Definition class plasma cutters (liquid cooled torches, oxygen as the plasma gas, sophisticated microprocessor controlled power supply and gas delivery system).....however the task of achieving lower speeds and better cuts on thin materials with an air plasma cutter is a tough one. I'm sure we will get it solved some day! In the meantine, use the low speed cut charts that are in the Hypertherm operators manuals!

Jim Colt Hypertherm

[motoguy]

Jim,

Thanks for the info. My Bulltear table doesn't have an issue at regular book speeds. I'd really just like to try to improve the detail if possible. Less heat, less arc "wander", etc.

I'll give the low speed charts a test, just to see what the difference is (aside from more dross! lol). I'm looking for the best cut quality, particularly on these ~1/2" high letters. Additional low-speed dross is an acceptable trade off.

[Brand X]

It's kind of funny Hypertherm offers a standard 30 amp nozzle for the 30XP, Just not for a 45XP. I know it's not for a machine torch, but looks like they seem to get the lower amp nozzles to work there.

[exapprentice]

Hi motoguy

I have used 30 amp consumables and the 30 amp cut charts using my PM 45 machine torch set @ 30 amps
works really well on thinner material and at slower feed rates than the std 45 amp consumables
I always use the 30 amp set up when cutting 0.9mm CR4 material

[jimcolt]

BrandX, It would be taking a step backwards to use the 30 amp T30 consumables as used with the original Powermax45. The Finecut parts used in the Powermax45XP (and the 65, 85 and 105) will cut with better quality, will cut at both slow and high speeds, and will last longer as compared to the old T30 design. I know you disagree, but I have a lot of experience with both...there is no comparison in regards to cut quality and life.

Jim Colt

It's kind of funny Hypertherm offers a standard 30 amp nozzle for the 30XP, Just not for a 45XP. I know it's not for a machine torch, but looks like they seem to get the lower amp nozzles to work there.

[Brand X]

I was talking you guys are making 30 amp nozzles for the 30 XP. Are those a step backwards too? I only ask because I had great results using the 20/30 amp consumables in my 30 amp Esab 400 (PT39 torch),and the Esab 1600 with the PT-37 machine torch. Worked great (IMO) Shielded/Unshielded.. I have some success using the 20,and 30 amp one torch stuff too..Although, not really close to the Esab stuff..(Unless I want fantastic low bevel .120 MS parts. Awesome, but more dross. Which is a good trade off for great looking parts..

I sold my 65, and kept the Machine torch for a 45/45XP down the road. I am in no hurry for the Low amp standard stuff, but will think hard about a 45XP when that time comes... I am waiting for Victors consumable upgrade and what Thermacut comes up with their new torch setup.. I have all the Thermacut, and Hypertherm consumables saved, when the right deal happens.. I like more options, and not less. I find I can get where I want that way..

PS,
I like the thin metal cutting using the finecut parts. Works well for me when all sorted. You can play with them, and get nice results.

[jimcolt]

Sorry Brand X,

I must have had Powermax30 on my mind, not the XP....which is a totally different animal.

I was talking you guys are making 30 amp nozzles for the 30 XP. Are those a step backwards too? I only ask because I had great results using the 20/30 amp consumables in my 30 amp Esab 400 (PT39 torch),and the Esab 1600 with the PT-37 machine torch. Worked great (IMO) Shielded/Unshielded.. I have some success using the 20,and 30 amp one torch stuff too..Although, not really close to the Esab stuff..(Unless I want fantastic low bevel .120 MS parts. Awesome, but more dross. Which is a good trade off for great looking parts..

I sold my 65, and kept the Machine torch for a 45/45XP down the road. I am in no hurry for the Low amp standard stuff, but will think hard about a 45XP when that time comes... I am waiting for Victors consumable upgrade and what Thermacut comes up with their new torch setup.. I have all the Thermacut, and Hypertherm consumables saved, when the right deal happens.. I like more options, and not less. I find I can get where I want that way..

PS,
I like the thin metal cutting using the finecut parts. Works well for me when all sorted. You can play with them, and get nice results.

[motoguy]

I'm getting ready to make my first cuts on some 063 aluminum. Book for my PM85 is 45A shielded, 45A, 325ipm, 136v. However, this is what I found from Jim, posted back in 2012. This will be an intricate part, so I need as much detail as possible.

"Cut quality on .063" aluminum will be almost identical with either the Powermax45 or the 65. With both systems I would use the 45 amp shielded process (as opposed to FineCut) consumables to cut aluminum down to .018" (26 gauge) with good quality.

If you do want a narrower cut path and slower cut speeds you can use the non shielded 30 amp consumables in the 45, and in the 65 you could use the FineCut consumables....cut quality would be very similar between these two processes.

The reason I prefer the 45 amps shielded consumables is that these consumables will provide the best consumable life...this is a result of their shielded design which is especially advantageous on aluminum. The difference in kerf width between the 45 amp shielded and the 30 amp (or FineCut) process is about .006"....which in most cases will not affect the parts you are cutting.

Speed can be an issue when cutting thin materials....the book specification for cutting .060" aluminum at 45 amps is 360 inches per minute. Cutting this same material with the 30 amp consumables requires 240 inches per minute. Aluminum can be cut at slower speeds...however if you cut too slow the kerf will get wider, and warpage could be an issue. I normally cut parts that have intricate detail at around 180 ipm with the 45 amp shielded consumables running at about 30 to 35 amps...excellent cut quality with just a small amount of "fuzz" on the bottom edge....this fuzz wipes off easily with a gloved finger."

Based on what I'm reading above, I need to take some test cuts at 180ipm, 32A (mid point of Jim's 30-35 comment), with 45A nozzle, at .060 cut height, and measure my voltage for my THC. Anyone else share their favorite settings for 060 (1.6mm) aluminum?

[nurbie]

Hey motoguy and Jim,
I've got a similar rig:
Starlab/PM85/C&CNC Bladerunner/CommandCNC Linux 32bit

I am also cutting thinner 16ga mild steel material, but more desiring PECKING and DEEP MARKING abilities.
I've got an Easyscriber to mark part #s but need to figure out a way to burn halfway through 16ga so I can 'fold' tabs and parts that can't be fitted into a pressbrake.
If not, then slots with tabs will be my only way; that's going to call for a LOT of TIG time to close up.

I tried setting 25a into my Sheetcam but I'm getting some fat kerf cuts using standard 45a consumables. It _looks_ same as 65a going through 1/4".
I haven't tried the fine-cut consumables yet, but I can tell I need better settings first.
The tool I set in Sheetcam for 16ga mild steel is this:
feedrate: 150ipm
pierce delay: 0.0
pierce height: .10"
cut height: .04"
preset current: 25a
air pressure: 75
preset volts: 49
tip size: 45a

Is this all wrong? I'm pretty new to this part, first tweaks.
Something in CommandCNC seems to be overriding the gcode, but if I'm close in Sheetcam then it must be down the chain.

I have no problem cranking out cuts with 65a, 1/4" mild steel!
Actually, that's not exactly true as my torch is a bit high/beveling in the bottom of hole cuts. Related?

Thoughts?

[nurbie]

I should say:
I'm (now) manually setting the PM85 to 25a and then running the cut profiles.
Didn't realize that CommandCNC does not set the amperage from the gcode; thought that was the whole point of the latest software / DTHC/other controls in the system (I'm running a CandCNC Bladerunner+CommandCNC)
friggin' n00b.

Even with regular purpose consumables I can get the torch cutting partially through the 16ga; it's almost doable!
Fairly fugly compared to how cleanly cuts are, kerfs are too wide with 45a consumables.
I'll try finecut consumables next; should make a big difference.
Had some DTHC issues so it's going to be a few weeks before I get my rig back/can test.

Just thought I should close out my previous comment as it was pretty uninformed.
Not that I know much more now...!

BTW,
Easyscriber tool advertised on this site . . . EXCELLENT TOOL!

[weldguy]

Interesting but I don't think you will be successful in piercing halfway through for the purpose of bending.. Why not use the Easyscriber to mark where the parts need to be bent in the pressbrake? And i agree the Easyscriber is an EXCELLENT TOOL