I have 2 nozzles with mine. One is a drag tip that has 3 equally spaced openings to let air in or blowback out (not sure) and the other is not a drag tip. So for the drag tip should I keep it off the cut material? I've been using an aluminum cutting guide and if I understand you right that may be contributing to my early nozzle wear when using the drag tip. Is that correct?
Best Way to Cut Steel Mesh with Plasma?
- Thread starter Hilbilly
- Start date
- Views: 10449
I have 2 nozzles with mine. One is a drag tip that has 3 equally spaced openings to let air in or blowback out (not sure) and the other is not a drag tip. So for the drag tip should I keep it off the cut material? I've been using an aluminum cutting guide and if I understand you right that may be contributing to my early nozzle wear when using the drag tip. Is that correct?
Big Barn
Super Member
- Joined
- Aug 20, 2013
- Messages
- 6,874
- Location
- Victoria, B C
- Tractor
- More than 40 over the years. Ten at any one time. Mostly Ford and New Holland
Hillbilly, this is the aluminum cutting guide I made for use with a drag tip. It is raised 1/4" above the material to be cut.
Aluminum vice jaw protectors with rare earth magnets press fitted in are JB Welded to the 1" aluminum angle. Terry
jimcolt
Gold Member
Different plasma manufacturers have different power supply and torch designs......so expect different performance and consumable life from brand to brand and between different models. Just to clarify a few things:
-The larger Hypertherm units (Powermax45 and larger) have a special control circuit for cutting expanded metal that rapidly lowers the amperage (and the heat load) on the nozzle orifice when it senses that the arc is not cutting metal. You will actually hear the difference in sound when the arc transfers, and ramps up the current as opposed to when it is maintaining the pilot arc in the air. This saves nozzle life over most plasma cutters that remain at constant current after losing the arc.
- Pilot arc is the arc that initially fires in the air before you start a cut. In a Hypertherm it is a much lower amperage arc (than you will have once cutting starts) and is at a different air pressure. Without this current and air flow technology....firing a pilot arc in the air will cause serious damage to the nozzle orifice. Note....some manufacturers call the nozzle a "tip".
-Continuous pilot arc is the pilot that re-fires if you hold the trigger switch on and move the torch away from work grounded material. On some torches this pilot stays at the same amperage as cutting....meaning the same energy that was cutting your steel is now being dissipated by the nozzle and the electrode. Better power supply designs (most Hypertherm's) use a "pilot arc controller" circuit to instantly ramp down current and change air flow in a way that preserves nozzle (tip) orifice life.
-Transferred arc is when the plasma arc is cutting metal, the current flow goes from the internal electrode, the nozzle has no current load, rather it is just used to shape the arc, and the current attaches to the work grounded material being cut. When this occurs....nozzle orifice life is maximized.
So....to cut expanded metal with a Hypertherm: Use shielded consumables, read the operators manual and switch to the "expanded metal cutting mode"....on some you need to adjust air pressure, others the air pressure is auto adjusted when you switch to this mode. On the Powermax 30 and 30XP you don't have to adjust anything, just cut expanded metal. There always will be more rapid wear when you allow either the initial pilot arc to occur for longer than necessary, or if you are doing a lot of expanded metal cutting with a high amount of pilot time.
Funny story: I once visited a site that build large underground storage tanks.....the user had some rework to do inside these tanks that meant sending a worker with a hand torch inside to do some cutting. The company complained about very short nozzle life doing this job so I went to investigate. Turns out the worker going inside the tanks did not have a light....so he simply fired the pilot arc and used that for his worklight. I gave him my flashlight, problem solved.
Jim Colt Hypertherm
-The larger Hypertherm units (Powermax45 and larger) have a special control circuit for cutting expanded metal that rapidly lowers the amperage (and the heat load) on the nozzle orifice when it senses that the arc is not cutting metal. You will actually hear the difference in sound when the arc transfers, and ramps up the current as opposed to when it is maintaining the pilot arc in the air. This saves nozzle life over most plasma cutters that remain at constant current after losing the arc.
- Pilot arc is the arc that initially fires in the air before you start a cut. In a Hypertherm it is a much lower amperage arc (than you will have once cutting starts) and is at a different air pressure. Without this current and air flow technology....firing a pilot arc in the air will cause serious damage to the nozzle orifice. Note....some manufacturers call the nozzle a "tip".
-Continuous pilot arc is the pilot that re-fires if you hold the trigger switch on and move the torch away from work grounded material. On some torches this pilot stays at the same amperage as cutting....meaning the same energy that was cutting your steel is now being dissipated by the nozzle and the electrode. Better power supply designs (most Hypertherm's) use a "pilot arc controller" circuit to instantly ramp down current and change air flow in a way that preserves nozzle (tip) orifice life.
-Transferred arc is when the plasma arc is cutting metal, the current flow goes from the internal electrode, the nozzle has no current load, rather it is just used to shape the arc, and the current attaches to the work grounded material being cut. When this occurs....nozzle orifice life is maximized.
So....to cut expanded metal with a Hypertherm: Use shielded consumables, read the operators manual and switch to the "expanded metal cutting mode"....on some you need to adjust air pressure, others the air pressure is auto adjusted when you switch to this mode. On the Powermax 30 and 30XP you don't have to adjust anything, just cut expanded metal. There always will be more rapid wear when you allow either the initial pilot arc to occur for longer than necessary, or if you are doing a lot of expanded metal cutting with a high amount of pilot time.
Funny story: I once visited a site that build large underground storage tanks.....the user had some rework to do inside these tanks that meant sending a worker with a hand torch inside to do some cutting. The company complained about very short nozzle life doing this job so I went to investigate. Turns out the worker going inside the tanks did not have a light....so he simply fired the pilot arc and used that for his worklight. I gave him my flashlight, problem solved.
Jim Colt Hypertherm
CNC Dan
Veteran Member
Listen to Jim Colt. He knows.
Any time you can keep the nozzle(tip) out of electrical contact with the work(or straightedge), the better.
Try to minimize pilot arc time.
