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Maintenance of your plasma cutting machine: A Step-by-Step Guide

Although a plasma cutting machine can be used for a wide variety of applications, there is one universal truth that is valid for any and all manufacturers out there: downtime is not an option.

This is because a plasma cutting machine is often a crucial bottleneck in the overall production process, and the moment it goes down production goes down, which means costs will start accumulating.

But even before your machine fully breaks down, smaller issues could already lead to an inferior cut quality or potentially start a domino effect of component failures.

Can routine maintenance of your plasma cutting machine help you spot important issues before they cause a cascade of malfunctions and ultimately prevent dreaded downtime?

Absolutely!     

This is why we will show you a step-by-step guide on how you can maintain your plasma cutting machine.

Check for wear on the mean contractor of a plasma cutting machine

Proper maintenance of a plasma cutting machine is critical to ensure cut quality, within-tolerance parts, longer consumables life, and to avoid downtime.

As a plasma cutting machine relies on the collaboration of many complex hardware & software systems, routine maintenance should be done by experts. Also, proper training of your operators can help to avoid issues, as well as prolong the life your consumables

We will explain in this article why maintenance of a plasma cutting machine is important, when you should replace your consumables and a step-by-step guide on how to do preventive maintenance of a mechanised CNC plasma machine

 

Importance of Plasma Cutting Machine Maintenance

You need to keep in mind that CNC plasma cutters are very complex machines. Unlike more simplistic mechanical machines, they will not keep running just by “greasing their gears”.

A plasma cutting machine relies on the constant complex interaction of different components and systems, including motion control components such as drive motors, gearboxes and drive amplifiers, torch height control, gas flow control, several complex software elements (CAM, CNC, motion control), and of course the plasma cutting system itself. With the last one being a hyper-complex piece of technology all by itself.

In order to make sure that all of these individual components and software elements are in perfect working order, as well as interacting with each other in a smooth and coordinated way, a proper maintenance routine of your entire CNC plasma cutting machine should be a critical part of any production process.  

Preventative Maintenance of a Plasma cutter is essential

Preventative Maintenance of a Plasma cutter is essential

When to replace consumables without wasting money

Just by using your plasma cutting machine your consumables will wear. This is absolutely normal is linked to the physical wear and tear of those components while creating a plasma arc.

Timely replacement of these consumables is needed to ensure consistent, high quality cut quality, but also to prevent and avoid total failure which could potentially damage other components of the machine.

In order to avoid such issues, many companies have put specific policies in place to ensure timely replacement of their consumables. Making the habit an integral part of your production process is definitely a smart approach.

However, this sometimes also leads to overkill.

Some companies will take the idea to far, and have strict policies to replace all consumables after every shift or batch.

This general approach could lead to one or several consumables being prematurely replaced, which at the end of the year could mean a significant and unnecessary extra cost for a company.

So when will a certain consumable really needs to be replaced?

Right of the bat, there is no rule of thumb that can be applied to all situations. The wear out of consumables is influenced by the application’s power level, material thickness, the amount of cutting the torch does, but also the operator technique.

For example, on most plasma torches, the electrode and nozzle do not wear at the same rate. Which means the optimal replacement moment for each can differ. 

On the other hand, an insufficiently trained operator could use the wrong torch height settings leading to faster a faster deterioration of the torch. Or even worse, wrongfully using petroleum lubricant on the O-rings could cause a fire in the torch and burn it.

Inspect O-rings of your plasma cutting consumables

Inspect O-rings

The key to getting timely consumables replacement right is to have the right expertise. Therefore, we recommend training your operators or contracting preventative maintenance service. Trained operators are far more likely to properly identify wear out on different consumables and use the optimal techniques for operation. This could save your shop a lot of money being spend on consumables while avoiding issues & and dreaded downtime. If you want to know more information about each specific consumable and tips on how to spot when they should be replaced, we recommend you to read this separate article the different consumables and how long they last. Changing consumables will probably be one of the most frequent acts of maintenance you will perform. But proper maintenance of a plasma cutting machines goes way beyond just timely consumables replacement. In the next section we will cover the 15 steps of an effective routine maintenance.
plasma cutting consumables maintenance

Plasma cutting consumables maintenance

how to maintain a mechanised CNC plasma machine?

A regular preventive-maintenance routine ensures your CNC plasma cutting machine continues to perform as designed and can help prevent smaller issues to ultimately lead to a major problem that causes machine downtime.

So how do you do proper routine maintenance of a CNC plasma cutter?

In the next few subsections, we will provide you with 15 steps, divided in daily, weekly and monthly tasks, that together constitute a very decent check-up of your overall machine.

However, following these steps by no means guarantees that no other issues can arise. In case you still experience issues or imperfect cutting results post-check-up, we strongly recommend you contact a skilled technician to come over and have a look.

Before we start though, perhaps some tips on how to prepare for preventative maintenance of your plasma cutting machine:

1. Disconnect Power

In case you are opening up the machine for maintenance operations, ensure the power is disconnected and all gas flows are closed. Also be mindful of residue gas in the lines.

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2. Foresee Space

Ensure you have sufficient working space around the machine in which you can safely operate. There have been accounts of technicians accidents involving forklifts or carts. If possible, work on the machine outside of key production moments in your facility.

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3. Foresee A Work Bench

Foresee a clean and ample work bench to place components, bold heads and other small items. If you are not fully accustomed with a specific machine, take notes and or pictures, or preferably refer to a skilled technician.

4. Consumable Tool at Hand

When replacing consumables, make sure to have a proper consumable tool at hand.

5. Remove flammable materials

In case you need to use welding apparatus or other flammable equipment on the outer casing, ensure there are no flammable materials nearby or residue on the machine (oil, dust, gas).

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6. Ask For Help

For more intrusive maintenance, always be accompanied by a second person. Even if he or she is not a skilled technician, you are working with heavy and complex machinery so better to be safe than sorry.

if the highest accuracy is required a fiber laser is your best option

Have the right consumable tool at hand

Routine Daily checks

Once you are fully and safely set up, you can move the actual maintenance steps of your plasma cutting machine. 

First up are the routine daily checks that an operator should do before starting his shift:

1. Verify the inlet gas pressure

In case your plasma machine is fitted with an autogas system, this step can easily be done by running the preflow and cutflow test in the diagnostic screen.

For manual gas systems confirm the inlet gas pressures are conform the guidance in the machine manual.

Confirm that ALL inlet gas pressures are 115 PSI (8.3 Bar) [± 15%]

Confirm that ALL inlet gas pressures are 115 PSI (8.3 Bar) [± 15%]

test cutflow & test preflow on an automated gas plasma system

On an Auto Gas system: Navigate to the diagnotiscs screen and check inlet gas pressures in “Test Preflow” and in “Test Cutflow”

2. Inspect the air filters

Inspect all air filters for moisture, oil and particulates. If a filter is dirty or dark instead of white it should be replaced.

On the back of both the Selection and Gas console there is an air filter.

On the back of both the Selection and Gas console there is an air filter.

Remove metal protective jacket

Remove metal protective jacket

Clean Air filter

Look through the sight glass to see if there is any water, oil or particulates. The result should be just like the picture above.

Dirty Air filter with Oil and Water

Dirty Air filter with Oil and Water

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3. Check the coolant level

If the level is below (or near) the “low” marker of the coolant reservoir, replenish it using a premix coolant that meets the requirements in the manual.

Verify as well if the coolant is either pink or colourless. If the colour is grey or black, your pump is most likely failing.

To note, If you use just distilled water, you need to add a corrosion inhibitor like benzotriazole. Benzotriazole prevents corrosion and inhibits algae growth.

Check if the Coolant Level of your plasma cutting machine is high or low

Verify that the coolant level in the tank is full. If the level is low add coolant

Hypertherm Torch Coolant

Verify that the color of the coolant is either pink or colorless and check the coolant tank for dirt and particulates. 

4. Clean the torch body

Remove the torch from its mounting tube and do a first visual inspection. Look for excessive burn marks, cracks, traces of molten metal.

Also, inspect the mounting tube and the torch lead fittings. Firstly, give them a good blow to remove excessive dust.

Make sure all the connections remain undamaged and look for signs of leaks or residue build-up. Now it’s time to have a closer look at the torch itself.

Carefully remove the different torch parts and again inspect each of them closely. Look for signs of mechanical damage to threads. You can clean the inside of the torch with a soft cotton swab.

Use a bit of electrical contact cleaner to get the grime out easier. In case you find indications of wear out (e.g. the O-rings), replace the component or go for a full new torch. 

clean torch with a cloth

Use a clean cloth to wipe off the torch inside and outside.

Clean torch with a swap

A cotton swab can be used to access hard-to-reach internal surfaces.

Clean torch with compressed air

Use compressed air to blow away any remaining particulates from internal and external surfaces.

5. Clean the torch leads

It’s important to remove any accumulated metal dust or other particles from the torch leads.

When a plasma arc is started, a high voltage current will run through the leads. If this current, however, encounters metal dust on its path it will dissipate that energy and potential block the arc from starting.

Related to this, you will also want to double-check whether there is proper grounding to earth via high-frequency shielding.

Finally inspect the leads for any abnormality such as kinks, tears, exposed wiring, etc.

When reinstalling the torch, make sure it is properly mounted, perpendicular to the table.

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6. Check the gas quality

Hold a clean paper towel under the torch and purge air through the system you the test mode. You don’t want to see water, oil mist or any particulates.

Contaminated gas flow can lead to inferior cutting quality and shorter consumables life.

Routine Weekly Checks

The following plasma cutting machine maintenance steps should be done on a weekly basis, or sooner if you start to see indications of a cut quality or consumables issue.

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1. Inspect all hoses and leads

Carefully check all hoses and leads for wear and restrictions (e.g. kinks or sharp bends). If the outside insulation has been cut or otherwise damaged, replace the cable.

Check Gas lines on a plasma cutting machine

Check gas lines

Check for Wear on Leads and hoses

Visually inspect all hoses and leads for wear and restrictions.

2. Do a gas leak test

In case your machine is fitted with an autogas system the software can run an automatic gas leak test. Do this once a week to be sure there are no (minor) leaks.

Certain manual gas systems are also able to do a gas leak test. For how to do this please consult your machine manual.

gas leak test with an autogas plasma cutting system

test for bad inlet valves, check for gas leaks
between the selection and metering console, and test the proportional valves

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3. Check the coolant flow

Check the flow rate shown on the gas console (manual gas) or on the CNC’s diagnostic screen (auto gas).

If the flow rate has decreased and is below the recommended levels in the manual contact your maintenance department to service the coolant system.

Insufficient coolant flow can cause the torch to overheat.

Coolant flow test on a mechanized plasma cutting table

If flow rate has decreased and is below 2.9 lpm (0.75gpm) contact your maintenance department to service the coolant system.

Routine Monthly Checks

Thirdly, an adequate plasma cutting machine maintenance should include the following monthly checks:

10. Clean out the power supply

Before you open up the power supply, double-check whether all electrical power has been disconnected and the line disconnect switch is the off position. 

Remove the cover and either vacuum or blow out any dust or particles using compressed air. This needs to be done as metal dust can cause damage to the internal components.

Also, check the filters and fans and replace them if needed.

11. Check system grounding

Verify that all components of the system (power supply, ignition console, etc) are individually grounded.

Proper grounding on a CNC Plasma Cutter

Proper grounding on a CNC Plasma Cutter

12. Check for cooling system leaks

Inspect the coolant’s circulating system for coolant leaks at all connection points.

Coolant system leaks

Coolant system leaks

13. Clean machine components

Remove grease, dirt, and metal dust from the rails, gears, racks and other components.

You can do this by using an abrasive pad and some degreasing agent.

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14. Align rails, gears & bearings

Check whether the rails are still aligned and have even distances across the entire length.

Misalignment can cause drag of the drive motors. Adjust gear alignment to remove play between gears and racks.

Check whether the bearings have minimal play between them and the rail or crossrail surfaces.

15. Check drive motor & control

In case you have noticed the drive motors seem to be out of synch, or if the torch is not returning correctly to its home position, the motors and/or control might need to be tuned.

This can be a tedious and complex process, please make sure to consult your machine manual or to contact an authorized technician.

These days, all this diagnostic information can be made available on a very detailed level via intelligent real-time information software like IRIS. This kind of software could minimise your machine downtime and avoid unnecessary costs.

Request Cutting samples from your OEM Plasma cutter manufacturer

Machine Health information with IRIS

The Need for expertise

The previous topic covering the different daily, weekly and monthly tasks shows that maintaining a plasma cutting machine can be a very complex thing. That is why it is absolutely crucial you properly train your operators or maintenance crew to be up for the task.

Standardizing routine controls and checks in a checklist can help to ensure all maintenance steps are executed in a complete and timely fashion.

CNC Plasma cutter maintenance checklist

CNC Plasma cutter maintenance checklist

Seeing the complexity of the machine maintenance, many companies also rely on an external service provider or the machine producer to service their machine. This can range from 1 to 4 times a year, depending on your application and #cutting hours.

Outsourcing the maintenance offers, of course, many advantages. It is fast, easy, and you don’t need to train your own people as thoroughly.

On top, if the machine producer works with its own technicians chances will be high replacement parts will at hand if issues are discovered during a routine maintenance check.

What if your plasma cutting machine has broken down?

Despite your best efforts to properly maintain your plasma cutter something still went wrong and your machine has broken down?

Then check out our separate post on repairing your plasma cutting machine

Conclusion

So there you have it. We hope you found these tips useful and you are now fully set to perfectly maintain your plasma cutting machine and ensure the continuity of your production.

In case you’re looking for expert help or have any questions regarding preventive maintenance of your plasma cutting machine, the Esprit team is happy to help.

Esprit Automation is a leading manufacturer of CNC plasma cutting machines and is able to service most machines, regardless of the producer.

CONTACT US For all your Plasma cutting maintenance needs

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