When it comes to plasma cutting, the components of the plasma cutter or the consumables play a very important part in achieving high-quality and precise cuts. All the components depend on each other and if one component is faulty, it affects the performance of the others too.
Here, we will be discussing about the consumables in the torch of a hand-held plasma cutter and how to look for signs that indicate when a consumable is failing. We will also look at proper torch maintenance to ensure the optimal working of the various components.
As we know, the most important components in any manual plasma cutter that makes up the torch are: the nozzle, shield, electrode, swirl ring and retaining caps.
Signs That a Consumable Is Worn Out
The copper nozzle in the plasma torch has a tiny orifice that constricts the plasma arc. Due to regular use of the plasma cutter, the orifice becomes bigger and also out of shape. Although, the swirling gas cools the nozzle, the orifice still remains quite hot. Ultimately, the orifice becomes so large that the constricted arc is lost.
Also, the kerf of the metal that is removed when cutting becomes wider. As the arc is not very constricted, the cutting speed also reduces. The heat is dissipated instead of being focussed in one place. All this is caused because the nozzle is worn out. When you look at the nozzle orifice and find that it is oval-shaped or very large, then it is time for the nozzle to be replaced.
With regular use, the tungsten or hafnium element present in the electrode becomes molten and as you start cutting, the pieces are blown out via the nozzle. A pit is formed in the front portion of the electrode. When the pit is more than 1/32, it means that the electrode needs to be replaced. If the electrode is not replaced when the element is depleted, the torch will stop cutting as only the copper is burning now. The arc also begins to glow with a green colour. The entire top portion of the electrode will burn off causing the torch to get extremely heated and this will cause plenty of damage.
It is recommended that you change the electrode along with the nozzle. If you replace them one at a time, then you may be compromising the cut quality.
With continuous use of the torch, there is no real damage to the swirl ring. The swirl ring can get damaged if it is dropped or due to heating and cooling in the long run. If the swirl ring cracks, it cannot channel the gas properly and it must be replaced. With every 5-10 changes of the electrode and nozzle, the swirl ring must be replaced.
You must watch out for any cracks that develop in the retaining cap because of drops. Any build-up of slag on the shield can cause the airflow to be restricted. Therefore, you must ensure that there is no excessive build-up of slag on the shield.
We can see that the consumables of a hand-held plasma cutter are very crucial for the proper working of the torch and the cutter. In order to maintain precision and high-quality cutting capability of the torch, you must ensure regular inspection of the consumables and replacement of worn out parts. We will be discussing the importance of consumables maintenance in Part 2 of this series.