How to maintain a plasma cutting machine?

Plasma cutting is a staple machine in metal fabrication. Since its introduction in the 1950s, it has been an effective method of cutting all types of metals. Utilizing a combination of electricity and gas, an electric arc is formed as it shoots out of a nozzle at high speed. This generates enough heat to cut any type of metal. However, plasma cutting, like any other machine, is prone to damaging parts. This is mainly due to the natural wear and tear of the parts over time. The best thing you can do to prevent this from happening is to keep your machine in the best possible condition and follow a strict preventative maintenance checklist. This is to ensure that your machine runs at its best and extends the life of your machine. The next part of this article will show you how to maintain your plasma cutter.

1. Importance of plasma cutting machine maintenance

2. How to maintain the plasma cutter?

3. How to extend the service life of plasma cutting machine accessories and parts?

1. Importance of plasma cutting machine maintenance

You need to remember that CNC plasma cutters are very complex machines. Unlike simpler mechanical devices, they don't just "grease the gears" to keep them running. Plasma cutting machines rely on the constant and complex interaction of different components and systems, including motion control components, torch height control, airflow control, several complex software elements (CAM, CNC, motion control), and of course, the plasma cutting system itself. To ensure that all of these individual components and software elements are in perfect working order and interact with each other in a smooth and coordinated manner, proper routine maintenance of the entire CNC plasma cutting machine should be a critical part of any production process.

2. How to maintain the plasma cutter?

(1) Ensure correct pressure and flow rate.

Correct plasma pressure and flow rate are very important for the life of the consumables. If the air pressure is too high, the life of the electrode will be greatly reduced; if the air pressure is too low, the life of the nozzle will be affected. Please refer to the instruction manual of the CNC plasma cutting machine carefully when setting.

(2) Adopt reasonable cutting height.

Cutting height is the distance between the cutting nozzle and the surface of the workpiece. This distance should be kept as constant as possible, usually about 3-8mm. If the distance is too close, the service life will be reduced or even burned out after installation.

(3) The thickness of the perforation and cut should be within the limits allowed by the plasma cutting machine.

The plasma cutter cannot perforate steel plates that exceed the working thickness. The usual perforation thickness is 1/2 of the normal cutting thickness. Try to cut within the normal cutting thickness rated by the plasma cutter, and try not to cut on the limit cutting thickness. The normal cutting thickness of the CNC plasma cutter is usually 60% of the maximum cutting thickness labeled by the manufacturer, and try to cut within this thickness range for the best protection of the cutting opening.

(4) Do not overload the nozzle.

Overloading the nozzle (i.e. exceeding the nozzle's operating current) will quickly damage the nozzle. The current strength should be 95% of the nozzle's operating current. For example, the current strength for a 100A nozzle should be set to 95A.

(5) Keep plasma gas dry and clean.

Plasma cutting systems require dry, clean plasma gas to operate properly. Checking the quality of the gas powering the plasma cutter is critical to maintaining both cut quality and service life. The gas quality is tested by placing the torch in a test position and placing a mirror underneath it to consume the gas in the torch. If vapor or mist appears on the mirror, the cause needs to be identified.

3. How to extend the service life of plasma cutting machine accessories and parts?

(1) Cutting should start at the edge: Whenever possible, start cutting at the edge rather than cutting through holes. Using the edge as a starting point will extend the life of the consumables. The correct method is to aim the nozzle directly at the edge of the workpiece and then start the plasma arc.

(2) Avoid stretching and extension of the plasma arc: If the plasma arc can only reach the surface of the workpiece by stretching and extension, the plasma arc will create this stretching and extension at the beginning and end of the cut, which can cause abnormal damage to the nozzle. This problem can be avoided if the correct edge-starting technique is used and the proper "arc-break" signal time is selected.

(3) Reduce unnecessary "arc start (or lead-in) time: the nozzle and electrode are consumed very quickly during arc start, and the torch should be placed within walking distance of the cut metal before starting the arc.

(4) Apply a splash-proof chemical coating to the protective casing: The splash-proof chemical coating helps to minimize slag buildup on the protective casing. However, the protective casing must be removed from the torch before applying the anti-spatter coating.

(5) Remove slag from the protective casing: Slag on the protective casing of the torch should be removed frequently, otherwise this slag can cause destructive heavy plasma arcs.

(6) Remove gas after replacing wearing parts: After replacing wearing parts or after a long shutdown, a gas purge should be carried out (2-3 minutes is appropriate) to ensure that the water mist in the torch is discharged.

(7) Keep the torch and wearing parts as clean as possible: any dirt on the torch and wearing parts will greatly affect the function of the plasma system. When replacing wearing parts, place them on a clean flannel, check the torch's connecting rib frequently, and clean the electrode contact surfaces and nozzles with a hydrogen peroxide-based cleaner.

(8)Removing oxidization from air or oxygen nozzles: When air or oxygen plasma is selected, oxides can be deposited in the nozzles, which can interfere with the airflow and reduce the service life of wearing parts. Wipe the inside of the nozzle with a clean flannel to remove oxides.

Are you looking for a plasma cutter? You can extend the life of your plasma cutter if you follow this maintenance guide. If your machine does need to be replaced, then you need our help. Shandong U-May Cnc Technology Co., Ltd. specializes in providing efficient plasma cutting machines with machine parts from trusted and well-known industry leading brands. If you have any need for a CNC machine, contact us! Our highly trained staff can help you in any way you need when you are looking for a new plasma cutting machine or other CNC milling machine.