The Common Plasma Cutting Mistakes And Their Solutions

Congratulations!

For being the owner of the most functional and reliable plasma cutter.

If not so, hope you’re going to be the proud owner of this machine very soon.

Whatever, the cold hard truth is that you may do some common plasma cutting mistakes while using it.

Don’t be worried.

We’ve given our full efforts to compile most of the common mistakes of plasma cutting, their effective solutions as well.

Operator, welders, shop foremen, maintenance men, DIY expects that their plasma cutters will perform at a high level. But some mistakes are common that you may perform while using. Taking a look at some common mistakes and their solutions will definitely be helpful to the user.

Learn the common mistakes, solve them easily and effectively use the plasma cutter.

Let’s Start!


To learn the common mistakes and their solutions

Using Worn Consumables

Using worn consumables is a big mistake for plasma cutting. It’ll not only ruin a good piece of metal, but also can cause torch failure.

Moreover, it’ll cause unnecessary downtime. But you can easily avoid these situations. There are several ways to identify the worn consumables.

A skilled operator can easily identify this by the subtle changes in the torch height or the sound or color of the arc.

However, the best way to diagnose the conditions of the consumables is to inspect the cut edge quality of the metal and the torch parts when the cut edge begin to worsen.

Maintain a record of average part life over time. This will help you to establish guidelines for checking and replacing the consumables.

Frequent Changing Of Consumables

It’s another mistake of using a plasma cutter. Change out the consumables too frequently is an expensive practice as well as the common mistake. Before changing any consumables you should learn when you need to change it.

  • If a nozzle is scratch inside or outside or if the hole is worn out of round, it needs to be replaced. Until seeing these signs, you may reuse the nozzle. Observe the shape of the aperture holding it up to light, you can easily find out whether it need to be changed or not.
  • Check the pit of the electrode element. Usually, it shouldn’t be more than 3/32" for air and O2, and 1/8” for Ar-H2 or N2. If the pit is found deeper than 1.0mm for the hafnium insert, it’s considered to be spent and needs to replace.
  • If you observe dirt or grease in the holes, arc burns, cracks or excessive wear, the gas swirler need to be changed.
  • You should replace the shields only if you observe signs of physical damage.

Using The Wrong Consumables And Parameters

Using the wrong consumables and parameter lead to shorten consumable life and reduced cutting quality.

While selecting the consumables, take into account the material types and thickness being cut, the plasma gas used, the amperage, other parameters as well.

The appropriate consumables must be used with the correct arc voltage, height, pierce delay etc. Reading the operator’s manual will help you to determine correct consumables for various types of cutting.

The best cutting results and consumable life are achieved when the correct amperage setting is used. At the lower amperage setting, the cutting results will be sloppy, whereas at too high amp setting, the nozzle life will be reduced.

Incorrect Assembling Of The Torch

The improper assembling of the torch hampers the electrical contact and flow of gas. Hence, correct assembling of the torch is important.

While assembling the torch, be careful to align its parts correctly and fit together easily. During changing parts, pay attention to keep the consumables clean to prevent the metal dust and dirt from contaminating the torch.

Maintaining cleanliness is important during torch assembly. O-ring lubrication should be just enough to put a shine on it. No other lubrication is needed at all.

Avoid using too much lube. It will cause clogging of the swirler and ultimately metal dust contamination in the torch.

Not To Maintain The Routine Maintenance

It’s the mistake that affects greatly on the performances of the plasma cutter. Proper care ensures the durability of the torches. It may last for the month or even years.

Be careful to keep the torch thread clean. Make sure to maintain a contamination and mechanical damage free working spot. Metal dust, excess o- ring lubricant or dirt should be cleaned out of the torch.

You can use hydrogen peroxide, electrical contact cleaner or a cotton swab to clean the torch.

Try to periodically check and lubricate the O- ring.

Not Monitoring The Gas And Coolant Flow

Neglecting the monitoring of the flow and pressure of the gas and coolant is a common cause of torch and consumables failure. So, it’s important to check it every day.

Due to insufficient flow, the consumables won’t be cooled properly and their life will be lessened. So, monitor the coolant level regularly.

Constant gas pressure is essential to maintain the cutting arc. But excess gas pressure causes the torch failure to start an arc in spite all other conditions are perfect for normal operations. It also creates rapid decaying of the electrode.

Compressed air is prone to moisture, oil and other contamination. So, you should keep the gas clean to prevent short torch life and consumables.

Piercing Too Low

This is another common error while cutting with a plasma cutter. The distance between the metal and the tip of the torch is important for both cut quality and consumable life. A slight variation in the torch height significantly affects the cut surface.

If the pierce height is too low, it causes molten the work piece to sprinkle the front of the shield and nozzle, causing subsequent cut quality problem and damage to the parts.

If the torch runs through touching the metal or drag along the surface, the arc may blow out. It may destroy the nozzle, gas swirler, electrode and even torch.

1.5-2X is the recommended piercing height that protects the torch and consumables from being damaged.

Too Fast Or Too Slow Cutting Speed

Too fast or too slow moving of the torch affects the cut quality. Too slow speed causes wider kerf and excessive top disperse.

If you’re going too fast, you’ll see sparks shooting along the top of the metal, a narrow kerf and a small hard bead of slag.

At the suitable travel speed, the arc comes out at about 20-degree angle and in the opposite direction of the torch’s path.

"Stretching" The Arc

It may happen at the beginning and at the end of the cut if the arc has to expanse. It can damage the nozzle by cutting the side wall of the part.

Start the plasma arc with the nozzle opening directly centered over the edge of the metal when doing an edge start.

Programming of the lead out and timing of the arc off signal can minimize this effect.

Conclusion

Hopefully, you’re now aware of all the common mistakes of plasma cutting.

Are you still confused to solve these mistakes?

Obviously, not.

After reading our article, you’re now confident enough to effectively use your plasma cutter and overcome the mistakes that you may make.

Ronald Wilson
 

I’m Ronald, Specialist engaged in the manufacture of fabricated metal product. I’ve been involved in the fabrication industry since 1998. To continue my love in welding and to share my experience I’ve formed a research team and have created this website for our valuable customers.

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