Plasma cutting machines use a variety of consumables which need replacing periodically in order for your machine to function optimally. Keeping on top of your plasma consumables is essential if you want to ensure high-quality cutting, time after time.
Since your cutting machine is forever operating at extreme high temperature, keeping on top of these parts will also reduce the time involved in refining and processing the finished parts.
So let's look at the different consumables & accessories for plasma cutters.
What are plasma-cutting consumables?
Plasma cutting consumables, as the name suggests, are a set of consumable (replaceable) components in your plasma cutter that need to be replaced over time, due to natural wear and tear and the high temperatures of the plasma arc.
All of the consumables can be found inside the cutting torch where the plasma energy is focussed. Keeping track of the parts in your machine is essential to its maintenance and longevity.
The specific parts that need replacing include an electrode, nozzle, swirl ring, shield cap and retaining cap. Let's look at the functions of each of these machine parts.
The Electrode
The electrode is a narrow tube, usually made of copper with an insert of hafnium, which has excellent conductive properties.
The electrode receives an electrical current from inside the connected plasma torch, focussing the charge through its tip and creating an arc on the piece of work being fabricated.
The Nozzle
The nozzle is the fine tip that focusses the arc of plasma onto the workpiece.
Nozzles have different widths, the finer the nozzle, the more precision the cut. Wider nozzles are often used for gouging, where fine nozzles are used for detailed and intricate work.
The Swirl Ring
This is a small piece that sits inside the torch that swirls the gas around the plasma arc, creating an outer layer of gas. This layer of gas serves to focus the arc more directly, creating even more precision.
This gas flow is what actually makes contact with the nozzle, so the cooler temperature prevents it from burning, which increases the overall longevity of the parts.
The Shield Cap
As the name suggests, the shield cap forms a shield, protecting the torch and other components from the molten metal, sparks and other heat effects of the plasma cutting process. It shields the other components from unnecessary wear and tear that would otherwise happen.
The Retaining Cap
This important piece holds all the other consumable parts of the plasma torch together. Since its job is to do this, this component can bear a lot of the heat and wears down over time.
How to tell if my consumables need replacing
Inspect your machine, and its output frequently. If you start to notice degradation in the cut quality, then it's time to replace some of your components. The hole in the nozzle wears away, getting wider. As we explained earlier in this post, the width of the nozzle impacts the precision of the cut, so a wider nozzle will produce a wider cut (Kerf) in the piece of work. A visual inspection is often enough to see if the nozzle needs replacing. Compare with a new nozzle to get a real visual comparison.
There isn't a time limit on how often you should replace the parts, as there are many variables to consider, including the frequency at which the equipment is outputting, the thickness and speed of the cut, and the amount of amperage.
Replacing the electrodes & Nozzles
The copper electrode with its hafnium insert conducts the electricity that produces the arc. Over time the hafnium melts creating a recess at the end of the electrode. As a rule of thumb, if the recess gets deeper than around 1.5mm, it’s time to replace the electrode. It is critical to replace it before the hafnium melts away, or you could face significant damage to the rest of the plasma cutter consumables.
It is sensible to replace the electrode and nozzle at the same time, based on whichever is the first to show signs of wear and tear. This will return your machine to optimal efficiency and cutting performance. Basically, it makes no sense to have a new nozzle with a worn-out electrode and so on.
Replacing Other Components
The rest of the components have a longer life span. They are most likely to receive wear from dropping, slag from cutting, the heating and cooling cycles, and thermal dynamics.
Inspect your parts visually. Check the retaining cap and the swirl ring for cracks and then replace them as soon as you notice any. As a rule of thumb, replace the swirl ring for every 4-5 nozzle and electrode replacement. Ensure you clean the shield cap regularly, remove any slag so that the airflow of the torch remains consistent. If the build-up becomes too large to remove, then it's time to replace the component.
How To Get The Best Lifespan out of your plasma cutter consumables
There are several factors that can influence how long your components last. To get the best out of your equipment and ensure the long-lasting output of your Kerf machine, check the following:
Correct Installation
Always ensure components are installed carefully and correctly in your plasma cutter if you want them to function properly. Ensure the tolerance of consumables matches the amperage you use.
Monitor For Wear & Tear
Inspect your machines plasma cutter consumables regularly. Ensure one component's wear and tear isn't causing damage and degradation to the other parts. Change the nozzle and electrode more frequently than other parts.
Ensure Correct Cutting Parameters
If you cut too slowly, too quickly or at the wrong distance, then your machine components will wear out faster than they should. Work within the proper parameters to ensure maximum efficiency.
In Summary
Replacing your plasma cutter consumables at the right time is essential for the overall maintenance and lifespan of your Kerf machine.
Kerf offer plasma cutting consumables for a range of plasma units including Air Liquide, Hypertherm plasma consumables, Kjellberg plasma consumables, and Lincoln Electric consumables.
