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What do you use for guided plasma cuts?

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greenbuggy

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Discussion starter · #1 ·
I've got a job coming up where I'm going to have to do about 20' of manual plasma cuts thru 1/4" thick material. Last time I did this job I used a thin piece of board which wasn't as straight as I'd like and ended up having to retouch a lot with the grinder.

Machine is an Esab PCM-750 with a Thermal Dynamics 1Torch 60A

The edge of my tip arcs on any conductive guides so I'm contemplating getting a long steel rule (~24-36") and gluing it to some sort of high temp insulator like Delrin with a few magnets attached to the Delrin to hold it in place on the steel I'm cutting. Anyone do something like this before? How did it work? Any other ideas I should consider before committing to build this?
 
#2 ·
I use this. I added a 1” x 1” x 1/8” aluminum angle iron to a magnetic burning square.
 

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#4 ·
Short cuts I use a speed square . Longer cuts i use whatever is close my homemade circle cutter works also
 
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#6 ·
Im not familiar with that set up, but the hypertherm plasmas ive used work the best with a drag tip and a 3/16" flat bar 3/16" away from the line. got a pic of your set up?
 
#9 ·
forhire said:
+1 drag tip. You'll need to shield body 9-8237 and drag cup 9-8235. Best upgrade I did on my hand torch. :)
View attachment 947281
Click to expand...
120 amp drag cutting is quite something.. (A-120) One torch on the Esab is a nice upgrade too..

I also put a SL-40 torch on the A-120 . Just to see what Kerf width I could get..Unbelievable really. 20-35 amp nozzle/machine turned to low..(Says 30 amps low-end) but I have my doubts there.. .035 SS..
 

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#10 ·
Hypertherm torches have drag cutting capability using the electrically isolated shield to protect the nozzle from double arcing to the material. They are designed to lay right on the material and guide along the edge of a thin piece of metal, wood, plastic, cardboard....whatever you have as a template or a guide.. You can cut repetitive parts very accurately with this design.

Most plasma torches do not use the (Hypertherm designed) shielded front end....and drag cutting forces you to lay the nozzle (often called a tip) right on the material for template cutting. This causes arcing from the inside torch electrode....to the nozzle, then to the material (known as "double arcing) ....and this causes the torch to try to stick (engineers call this "stiction") to the material creating a very rough cut edge. This double arcing also causes extremely short nozzle life.

Hypertherm developed shielded cutting technology in the early 1980's. Today the shield in a Hypertherm torch is used not only for efficient drag cutting (up to 200 amps) but the shield on newer Hypertherm torches uses Conical Flow technology to increase energy density of the arc (narrower, straighter cuts) while increasing nozzle bore cooling.

If you have a torch without shield technology you can drag cut on thin materials at low power (below 30 amps) effectively as the double arcing will be at relatively low power levels. There will be an affect on nozzle (tip) life. Above 30 amps the double arcing creates rapid nozzle wear.

Jim Colt Hypertherm
 
#12 · (Edited)

For most jobs I use a 6ft straight edge. About $10 from the big box store.

For longer cuts I've used a stick of 1/4"x2" flat stock. The edge isn't "precision" straight, but it's good enough for what I'm doing.
You might take a grinder and clean up one edge if you need something a little better.

I also use the shielded tip. I measure out my cut and make scribe lines. Then I unscrew the shielded tip and lay it on the work. I look through the hole of the tip and line up to one side of the scribe line. Then bump the straight edge against the tip and clamp it down. Do this on both ends of the straight edge. You should them be setup to drag down the straight edge and get edge of the cut really close to your scribe line.

Be aware the straight edge will heat up as you're cutting. If you have it tightly clamped on both ends, it'll want to expand and bow up. If you're on thinner material you can make the cut fast enough so this isn't a problem. If you're on thicker material you may have to clamp beside the straight edge so it's held in position, but can expand lengthwise.

Also I like to make a practice run before cutting. Just quickly slide the torch down the straight edge to see there are any little spots that might hang up. Knock them off with a chisel or grinder to get a smooth slide. Smooth slide -> good cut
 
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#13 ·
farmersamm said:
Personally, I don't like drag cutting. Copper doesn't slide as well as steel. Standoff guide slides very well against either aluminum, or steel, straightedge. But that's just me.
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The very best view is with a exposed tip, and no shield. Kicks the crap out of the shielded designs from anyone.. The guide rides on the tip the best too. A torch that does both is the best option.Thermal one torch for example.. Drag cut at 60 amps with the correct tips on some models.. Those wedge shaped shields last great but suck to use some times..Nice having some versatility in design.
 

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#14 ·
jimcolt said:
Hypertherm torches have drag cutting capability using the electrically isolated shield to protect the nozzle from double arcing to the material. They are designed to lay right on the material and guide along the edge of a thin piece of metal, wood, plastic, cardboard....whatever you have as a template or a guide.. You can cut repetitive parts very accurately with this design.

Most plasma torches do not use the (Hypertherm designed) shielded front end....and drag cutting forces you to lay the nozzle (often called a tip) right on the material for template cutting. This causes arcing from the inside torch electrode....to the nozzle, then to the material (known as "double arcing) ....and this causes the torch to try to stick (engineers call this "stiction") to the material creating a very rough cut edge. This double arcing also causes extremely short nozzle life.

Hypertherm developed shielded cutting technology in the early 1980's. Today the shield in a Hypertherm torch is used not only for efficient drag cutting (up to 200 amps) but the shield on newer Hypertherm torches uses Conical Flow technology to increase energy density of the arc (narrower, straighter cuts) while increasing nozzle bore cooling.

If you have a torch without shield technology you can drag cut on thin materials at low power (below 30 amps) effectively as the double arcing will be at relatively low power levels. There will be an affect on nozzle (tip) life. Above 30 amps the double arcing creates rapid nozzle wear.

Jim Colt Hypertherm
Click to expand...
Jim,
Is that true for the 380 also? I have one and can't find a drag tip (the castle turret type) anywhere for the torch. Is this because the torch designed for dragging? What about the FineCut consumables?
 
#16 ·
The Powermax30 is not a shielded torch...but because it is under 30 amps the damage (double arcing) caused by dragging is minimal.....so drag away. There are no Finecut consumables for the Powermax380. The newer technology Powermax30XP does have Finecut consumables available.

Jim Colt Hypertherm


AdVirMachina said:
Jim,
Is that true for the 380 also? I have one and can't find a drag tip (the castle turret type) anywhere for the torch. Is this because the torch designed for dragging? What about the FineCut consumables?
Click to expand...
 
#17 ·
BrandX.....I beg to differ you on this. There always is an advantage when the nozzle is non shielded for cutting in tight spots (the Hypertherm original Powermax30 is a great example) but if you are concerned with consumable parts life....dragging an exposed nozzle on any brand machine will not last even close to the life when dragging a shielded nozzle.

Jim Colt Hypertherm

Brand X said:
The very best view is with a exposed tip, and no shield. Kicks the crap out of the shielded designs from anyone.. The guide rides on the tip the best too. A torch that does both is the best option.Thermal one torch for example.. Drag cut at 60 amps with the correct tips on some models.. Those wedge shaped shields last great but suck to use some times..Nice having some versatility in design.
Click to expand...
 
#18 ·
jimcolt said:
BrandX.....I beg to differ you on this. There always is an advantage when the nozzle is non shielded for cutting in tight spots (the Hypertherm original Powermax30 is a great example) but if you are concerned with consumable parts life....dragging an exposed nozzle on any brand machine will not last even close to the life when dragging a shielded nozzle.

Jim Colt Hypertherm
Click to expand...

Fine,
but I still prefer the non shielded nozzle for cutting at 40 amps, and below.. There are a few reasons and kerf width is one of them. On the machines I drag with, I found you can buy China made tip/Nozzles to take almost all the sting out of the lower consumable life. Have to know which machine, and maker of the consumables to get success there. I still prefer the PT-31 XT torch and it's smaller head/ exposed tip for drag cutting overall. There is a member here that also found out how much he preferred that older style setup. Sold off his Hypertherm 600 (Bought new) and kept the Esab 650 with the PT-31XT torch. All this new tech stuff does not hold all the cards, and sometimes other things are just more important. In many ways goes for the new style Esab Torches too. Love the consumable life with the excellent shielded design, but still can't match the view of the cut line/etc... I was cutting with my SL-100 torch at 120/100 amps last night. Prefer just holding a standoff with the exposed tip then most drag-shielded setup.. In fact if I am going to drag cut anything thick I will use my Esab shielded PT-38 torch with my other machine.(similar to the new Hypertherm on layout) Many options on setup, and just have to find the one that works best for your application.
 

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#19 · (Edited)
But.....if you really need better access with a plasma torch.....these new HyAccess consumables were just developed by Hypertherm. Fully shielded for drag cutting at higher power levels. Available for the 30, 30XP and Powermax45. Eventually they will also be available for the Duramax torch.

Jim Colt
 
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