How Copper Electrodes Are Ruining Your Plasma Nozzle

copper-plasma-electrode-nozzle

A key component of keeping costs down, and production up, is treating your consumables well. Although they do need to be replaced at some point, it’s always ideal to keep them in good working order for as long as possible. In plasma cutting, one answer to longevity is using silver-tipped electrodes instead of copper.

Of all the plasma consumables, the electrode takes the hardest beating. Its job is to carry current from the power supply to the metal plate and maintain an airtight seal for equally high-pressure fluids and gases, both while exposed to hazards like plasma arc emissions and high-velocity gas jets. To protect it from the high heat generated by the plasma arc, the electrode emits hafnium, a high-melting-point metal that acts as a heat shield and helps sustain the arc.

The difference between copper and silver electrodes lies here, in the interaction of the hafnium with its surrounding metals.

Copper vs. Silver

In copper electrodes, hafnium serves as a barrier between the inner wall of the electrode and the high temperatures of the arc. It slowly wears away, however, and when it reaches 1mm in thickness it can no longer protect the copper. When the electrode fails the arc jumps back up into the nozzle, leaving you with two failed consumables and possibly a number of larger issues.

Silver, however, has a different chemistry with hafnium that allows it to last twice as long in a high-heat environment. As the hafnium wears down and start to lose its shielding power, a layer of silver oxide forms and conducts heat away from the electrode. As a result, a silver-tipped electrode can maintain good cut quality down to 2mm — double the depth of copper. And doubling the life of your electrode means doing the same for your nozzle.

When they fail, both copper and silver electrodes expel both hafnium and their own metal from the tip of the electrode into the nozzle. Silver, however, emits much less material because of its better conductivity and is less likely to attract the arc back into the nozzle.

Another difference between the two, of course, is price. With its better quality and longer lifespan comes a higher price — around 10 to 15 percent more than copper. When funding inventory for a large operation, that additional cost can add up quickly. To decide whether an upgrade to silver is right for your shop, be sure to weigh its additional upfront cost against your current budget for replacing inventory.

Advances in Silver Technology

Not all electrodes are created the same. So if you choose to switch up to silver, be sure you’re selecting the right electrode for your specific needs.  Design is equally important in reducing turbulence, stabilizing the arc and assuring smooth cuts.

To see the difference a quality silver electrode can make in your cut, schedule a free demo today.

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