I get these emails and phone calls every day about when to change consumables and how long they should last.
You should check your consumables before you start cutting and make sure they are good.
The electrode is the most important consumable as if its bad it can lead to torch damage faster then any other consumable.
The part of the electrode that makes the arc it called Hafnium, it is in the center of the electrode and will get 4000 degrees when cutting. As it wears little pieces fall out and you get a divot/hole in the end of the electrode. The Hafnium is only about 1/8" deep so you have to keep this in mind before making long cuts or cutting out something on a CNC table.
The time to change the electrode is when the divot/pit/hole in the end of the electrode get to be 1/16" deep or so.
There are a few other reasons to change the electrode also, even if it does not look bad. It is not firing dead center, this will cause poor cutting and excess tip/nozzle wear. Also a bad electrode will cause miss fires or pilot arc problems.
NOTE: YOU CAN NOT SAVE THE ELECTRODE BY SANDING, GRINDING, FILING OR WIRE WHEELING IT!!! SO GET THIS OUT OF YOUR HEAD!!!
This picture shows the Hafnium in the electrode and what happens to the electrode when it is all used up. I used a S45 electrode as a sample, but this will apply to almost all electrodes for all plasma cutters no matter what name you put on them.
If you have a Hypertherm Powermax plasma: 1. There is a page in the troubleshooting section of the operators manual that describes how to inspect the consumables and when to change them. 2. The hafnium emitter is bonded to the copper electrode body in different ways. Better quality electrodes made by Hypertherm have a proprietary manufacturing technique and use specialized copper alloy and hafnium diameter as well as a proprietary swaging technique to allow the best heat transfer (the hafnium temperature reaches about 3200 degrees F by the way) from the hafnium and the copper, providing from 5x to 10X more life than the lower cost copies and other brands. Using the electrode until catastrophic failure will not save you money, rather it will damage the nozzle and ultimately shorten the life of the torch. Change the electrode when the pit depth reaches .060" for best results and lowest cost per foot of cut. Jim Colt
so, what tool are you guys using to measure the 0.060 depth? Also, we ARE talking about the depth in the CENTER of the hafnium, right? I mean, I have electrodes with a “hole” in the center but lots of silver around the edge of the hole.
In the picture above, the Hafnium is the small gray colored piece directly in the center of the electrode that is cut in half. That is the only important part of the electrode. The silver stuff is just plating over the copper. It won’t stay silver for very long after the Hafnium is gone. It will become a molten pool of copper and your arc will turn green.
I’ll drag out my USB microscope tomorrow and post a sample. But, again, do you guys have a VERY skinny depth gauge or something?
You could probably use a pin adapter for a dial indicator on a setup.
I usually find that the nozzle goes first anyways and I just replace the set.
Just look at it. If it looks like about a 1/16 of an inch change it.
Here is a good video from Hypertherm on the subject.
looks like hypertherm recommends .040" as the replacement point.
I just eyeball them. .060" is the thickness of 16 ga metal.
This one is still fine.
This one, I wouldn’t trust on a longer cut, so I’d replace it.