Plasma Cutting. Anything I should know about Dross?.

[Industrial Toys]

I found some very attractively price CNC tables, some even using a hand torch and computer supplied by you. What would be the best size? 4x4, 4x8 or 5x10?

Maybe the better question would be, what to avoid?

I don't even have a regularly heated shop, and can't imagine keeping such a thing in an unstable environment.

And as far as making money. Most of the people I might be able to serve, I wouldn't even think of charging them for what I owe them already.

 

[Arc weld]

What shape are the consumables in your torch? You're having trouble getting a nice cut by hand on stacked sheets but instead of trying to figure out why, you want to spend thousands on a CNC table? Must be nice to have money burning a hole in your pocket. :confused3:

 

[Shield Arc]

What would be the best size? 4x4, 4x8 or 5x10?

I went with the 4' x 8' table. That is a common size plate. But you have to have a way to load the table with a full plate. I built a spreader bar, and bought suction cups. That way I could pick stainless steel, or aluminum plates too.

 

[Mysfyt]

What Arc Weld said. Your electrode and cup can have a huge impact on the quality of the cut. Not familiar with your unit, but when I ran a plasma table there were different size tips for different thicknesses.

Another thing is the quality of the air. Moisture in the air kills electrodes and tips fast. If you don't have access to dry air, try cutting with a tank of nitrogen.

As far as table size goes, get the biggest you can afford. No matter what you buy, there will always be something bigger you'll want to cut. But also consider the real estate that it will take up in a shop. It's not something you should move once it's set up.

 

[FredH]

Someone had posted a " Cut " sheet some time back that had pressure settings , etc.... , that I had saved , but can't seem to find it now . To much crap on my laptop now . Anyway , I'll second the " To Much Air pressure " statement . Cutting anything from 1/8" to 3/4" , I never changed my air pressure at the nozzle . It is basically set at 68 psi , again with trigger sqeezed . Without trigger sqeezed , it looks like it is around 72 / 73 psi .
As also noted , Flame through what you are cutting should be down , out the bottom , maybe slightly back from direction of travel .

Fred H.

 

[jimcolt]

FIG]473926[/ATTACH]Depending on which "upgrade" torch you have (could be the RT60 or the Duramax) will help me help you get the issue figured out. Your Powermax800 is a 20+ year old Hypertherm plasma....there actually have been 3 newer models in the same power range (50 to 65 amps) with the latest being the Powermax65.

Assuming you probably have the RT60 replacement torch....you can cut dross free on steel at up to 3/8" thickness. You should be referring to the operators manual for the RT60 torch....which will provide the correct part numbers for the 60 amp shielded consumables. There are also tips in the operators manual for cutting at the correct speed, inspecting the consumables....and setting the correct cut air pressure.

On the front panel of your Powermax is the cut pressure gauge. With air flowing at the torch (with new consumables....electrode, nozzle, swirl ring, shield and a good retaining cap) you need to verify that the inlet pressure (rear panel air inlet) is between 90 and 120 psi, then you adjust the regulator until the front panel cut pressure gauge is at 70 psi (air flowing at the torch). Too high and you will have rapid consumable wear and misfiring, too low and your cutting process will be under powered.

Make sure the work cable clamp is attached to clean metal....and following directions in the manual for proper speed, piercing technique, etc., you will be able to get clean cuts with excellent precision. Post pics of your torch and consumables....as well as letting me know what thickness you are having trouble cutting and I will help identify the torch....and help you out.

Cutting a stack of thin materials can be done well with plasma...but only if the materials are stacked tightly with no air gaps in between.

Dross is caused by: 1. Cutting way too slow, 2. Cutting too fast (in between too slow and too fast is the DFZ (dross free zone), 3.Cutting with the torch too high off the material, 4. Cutting with incorrect or damaged or worn out consumables.

I suspect you probably have incorrect or badly worn consumables in your torch. Feel free to contact me directly at jim.colt@hypertherm.com or respond to this forum so we can troubleshoot your issues!

I have a Plasmacam 4 x 4 cnc cutting table in my home shop....with a Powermax65 and machine torch mounted. This is a great home hobby shop cnc machine with the ability to cut precision parts from thin gauge to 5/8" thick (up to 1-1/4" thick with an edge start). Here are pics of some 1/2" plate I cut with the machine....as cut, no dross present.

Best regards, Jim Colt Hypertherm

Hypertherm Powermax 800 with upgraded torch.

Sometimes through my misuse, I end up with dross filling up the kerf.

I never seem to be able to cut through the dross with another pass. Usually I just break off the piece and grind it off.

Is there something about Dross I should know about?

Also, how well is a Plasma supposed to cut through multiple sheets of let's say 1/8" mild steel?

Thanks

 

[Industrial Toys]

As far as the table. I have always been facinated by computer run machines. Like plotters and CNC machines. It would be nice to make some real parts, although the cost is high for those parts. If I could see some revenue from such a table, that would certainly make more sense. It would also be a right off.