An air plasma cutting machine is a tool designed to cut medium and thin metal plates. It offers several advantages such as flexible and convenient operation, smooth workpiece incision, narrow cutting seam, small thermal deformation, easy slag removal and high cutting efficiency.
However, the cutting torch nozzle is subject to damage, which can negatively impact cutting efficiency and quality and, consequently, increase cutting cost.
To reduce the cutting cost and extend the service life of the electromechanical plasma cutting electrode nozzle, it is essential to consider the following points:
1. Ensure correct air pressure and plasma flow
Precise plasma pressure and flow are crucial to ensuring the longevity of consumable parts.
If the air pressure is too high, it can significantly reduce the life of the electrode.
On the other hand, if the air pressure is too low, it may affect the life of the nozzle.
2. Adopt a reasonable cutting height
Make sure to maintain a proper cutting height as per the operation manual, which refers to the distance between the cutting nozzle and the workpiece surface.
When drilling, it is recommended to use a cutting height slightly higher than the specified drilling height mentioned in the parameter table.
3. The perforation thickness must be within the allowable range of the machine system
The cutter cannot drill steel plates that exceed the maximum working thickness. Typically, the drilling thickness for cutting thinner materials (below 100A) is half the normal cutting thickness.
For example, if the 100A system is designed to cut one inch (approximately 25 mm) of carbon steel, the perforation thickness of the system should be 0.5 inch (approximately 12.5 mm).
4. Do not overload the nozzle
Exceeding the nozzle's working current, also known as overloading, can cause rapid damage to the nozzle. It is recommended that the current intensity be set at 95% of the nozzle working current. For example, if the working current of a nozzle is 100A, then the current intensity should be set to 95A.
5. Keep the plasma gas dry and clean
The plasma system requires clean, dry plasma gas to function properly.
Dirty gas is generally caused by problems in the gas compression system, which can shorten the life of consumable parts and cause abnormal damage.
To test the gas quality, place the cutting torch in the test state and hold a mirror underneath it to consume the torch gas.
If water vapor and fog appear on the mirror, you need to identify and correct the underlying cause.
6. The cut must start from the edge
Whenever possible, cut along the edge rather than through the hole. This approach will help extend the life of consumables.
For best results, align the nozzle directly with the edge of the workpiece before starting the plasma arc. This is the correct method to use.
7. Avoid plasma arc stretching and expansion
If the plasma arc contacts the workpiece surface only through stretching and expansion, it will cause abnormal damage to the nozzle at the beginning and end of plasma arc cutting.
This problem can be avoided by using the correct edge starting point technique and selecting the appropriate “arc break” signal timing.
8. Reduce unnecessary arc time (or arc guidance)
The consumption rate of nozzles and electrodes is high during the arc process.
Before you begin, make sure the cutting torch is positioned a reasonable distance from the metal being cut.
9. Apply splash-proof chemical coating to protective housing
The splash-proof chemical coating is effective in minimizing scum build-up on the protective housing.
However, it is necessary to remove the protective casing from the cutting torch before applying the spatter coating.
10. Remove scum from the protective shell
Always remove slag from the cutting torch's protective housing, otherwise it may cause a heavy and destructive plasma arc.
11. Remove gas after replacing consumable parts
After replacing consumable parts or during an extended shutdown, it is essential to remove the gas for 2 to 3 minutes to ensure that any water and mist are discharged from the cutting torch.
12. Try to keep the cutting torch and consumables clean
Any dirt on the cutting torch or consumables can significantly affect the functionality of the plasma system.
When replacing consumable parts, place them on a clean cloth. Regularly inspect the connecting rib of the cutting torch and use hydrogen peroxide detergent to clean the electrode contact surface and nozzle.
13. Remove oxides from air or oxygen nozzles
When air or oxygen plasma is used, oxide can build up inside the nozzle, which can disrupt airflow and reduce the life of consumable parts.
To avoid this, use a clean cloth to wipe the inside of the nozzle and remove any oxides.
14. Inject softened water into the cutting torch
Hard water can cause metal impurities to precipitate on the nozzle ring, causing interruption of airflow, reduced cutting torch quality, and reduced consumable life.
15. Check airflow and coolant flow every day
One of the most common causes of cutting torch damage is a lack of cooling flow. Therefore, it is essential to regularly check air flow and air pressure, including air or coolant cooling such as water cooling, to ensure proper operation of the cutting torch.
If you notice that the air flow is insufficient or leaks, it is essential to turn off the equipment immediately to eliminate the fault.
