I. Maintenance and care of CNC plasma cutting machine
The working environment of the CNC cutting machine is relatively harsh, with a significant amount of metal dust.
Therefore, the machine must be carefully cleaned and maintained, with designated personnel responsible for lubricating, repairing and maintaining the equipment.
1. Security operations:
- A CNC cutting machine is a precision device, therefore its operation must comply with fixed functions (designated operator, machine and station).
- Only professionally trained operators should use the machine. It is not for non-professionals.
- Before operation, make sure there is no external interference. After everything is normal, place the cutting board on the cutting deck. The plate must not exceed the cutting range (Note: Be careful when lifting it).
2. Daily maintenance and care:
- Every working day, the machine and guide rails must be cleaned of dirt to keep them clean. Turn off air and power sources when leaving work and release any remaining air in the machine's pipes.
- If the machine is left unattended for a long period, turn off the power to avoid operation by non-professionals.
- Make sure the machine's horizontal and vertical rails and rack surfaces have lubricating oil to keep them well lubricated.
3. Weekly maintenance and care:
- Every week, the machine must be thoroughly cleaned. Clean horizontal and vertical rails, transmission gears and racks and add lubricating oil.
- Check that the horizontal and vertical rail cleaners are working properly. If not, please replace them in time.
- Check whether all cutting torches are loose, clean the debris at the mouth of the ignition gun to maintain normal ignition.
- If there is an automatic height adjustment device, check whether it is sensitive and whether the probe needs to be replaced.
4. Monthly and quarterly maintenance:
- Check the main air intake for debris and that each valve and pressure gauge are operating normally.
- Check all air tube joints for looseness and all tube tracks for damage. Tighten or replace if necessary.
- Check all transmission parts for looseness and check engagement of gears and racks. Adjust if necessary.
- Loosen the tensioning device and manually push the cart. If there is any abnormal condition, please adjust or replace it in time.
- Check whether the clamping blocks, steel belts and guide wheels are loose. Adjust if necessary.
- Check the sturdy electrical panel and operating platform and whether any fixing screws are loose. Use a vacuum cleaner or blower to clean the dust inside the case. Check whether the head is loose (for details, see the electrical instruction manual).
- Check the performance of all buttons and selection switches. Replace the damaged ones, and finally draw a comprehensive detection figure to check the accuracy of the machine.
II. Plasma cutting torch maintenance
1. Mount the torch correctly:
- Assemble the torch correctly and carefully, ensuring that all parts fit well and that gas and cooling air can circulate. Place all parts on a clean cloth to avoid dirt. Apply an appropriate amount of lubricant to the O-rings, just enough to make them shiny. Do not apply too much.
2. Replace consumables in time:
- Do not wait until consumables are completely worn out to replace them. Heavily worn electrodes, nozzles, and rotational rings will produce uncontrollable plasma arcs, which can seriously damage the torch. Therefore, check consumables as soon as you notice a drop in cut quality.
3. Clean the torch connection threads:
- When replacing consumables or during regular maintenance checks, ensure that the internal and external threads of the torch are clean. Clean or repair connecting threads as necessary.
4. Clean the electrode and nozzle contact surface:
- In many torches, the contact surface of the nozzle and electrode is electrified. If these surfaces are dirty, the torch will not function properly. Use a hydrogen peroxide-based cleaner for cleaning.
5. Daily gas and cooling air check:
- Check gas and cooling air flow and pressure daily. If insufficient flow or leaks are detected, stop the machine immediately to resolve the problem.
6. Avoid torch collision damage:
- To avoid damage caused by torch collision, program correctly to avoid system overload. Installing anti-collision devices can effectively prevent damage caused by collisions.
7. Most common causes of torch damage:
- Torch collision.
- Destructive plasma arc caused by worn consumables.
- Destructive plasma arc caused by dirt.
- Destructive plasma arc caused by loose parts.
8. Precautions:
- Do not apply grease to the torch.
- Do not overuse O-ring lubricant.
- Do not spray anti-splash chemicals while the protective cover is still on the torch.
- Do not use a hand torch as a hammer.
III. How to extend the life of consumables
1. Ensure correct plasma pressure and flow
Correct plasma pressure and flow are essential to consumable life. If the pressure is too high, the electrode life will be significantly reduced; If the pressure is too low, the nozzle life will be affected.
2. Use a reasonable cutting distance
Follow the instructions in the manual and use a reasonable cutting distance – the distance between the cutting nozzle and the surface of the workpiece. When drilling, try to use twice the normal cutting distance or the maximum height that can be transmitted by the plasma arc.
3. The perforation thickness must be within the allowable range of the machine system
The cutting machine cannot drill steel plates that exceed the working thickness. Typical drilling thickness is half the normal cutting thickness.
4. Do not overload the nozzle
Overloading the nozzle (i.e. exceeding the nozzle's working current) will damage the nozzle quickly. The current intensity must be adjusted to 95% of the nozzle working current. For example, the current intensity for a 100A nozzle 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, often the result of gas compression system problems, will shorten the life of consumables and cause abnormal damage. Test the gas quality by putting the torch in test mode and placing a mirror underneath it. If moisture or fog appears on the mirror, identify the cause and correct it.
6. Start cutting from the edge
Start by cutting along the edge whenever possible, rather than drilling. Using the edge as a starting point will extend the life of consumables. The correct method is to point the nozzle directly at the edge of the part and then start the plasma arc.
7. Avoid prolonged extension of the plasma arc
If the plasma arc can only reach the workpiece surface by extension, this extension will occur at the beginning and end of the cut, causing abnormal damage to the nozzle. By using the correct edge start technique and selecting the appropriate “arc off” signal timing, this problem can be avoided.
8. Reduce unnecessary arc starting time
The nozzle and electrode wear quickly during arc initiation. Before you begin, place the torch within walking distance of the cutting metal.
9. Apply anti-splash chemical coating to protective coating
Anti-splash chemical coatings help reduce scum build-up on the protective layer. However, apply the coating only after removing the protective cover from the torch.
10. Remove scum from the protective shell
Regularly remove slag from the torch protective housing; otherwise, the slag will cause destructive double plasma arcs.
11. Purge the gas after replacing consumables
After replacing consumables or after a long shutdown, purge the gas (for 2 to 3 minutes) to ensure that water and mist are expelled from the torch.
12. Keep the torch and consumables clean
Any dirt on the torch and consumables will significantly affect the functionality of the plasma system. Place consumables on a clean cloth when replacing them, regularly check the torch connection threads, and clean the electrode contact surface and nozzle with peroxide-based cleaners.
13. Remove oxides from air or oxygen nozzles
When using air or oxygen plasma, oxides will build up inside the nozzle, affecting gas flow and reducing consumable life. Wipe the inside of the nozzle with a clean cloth to remove oxides.
14. Use softened water on the torch
Hard water can deposit metal impurities on the nozzle ring, affecting gas flow, reducing torch quality and shortening consumable life.
15. Check airflow and cooling flow daily
One of the most common causes of torch damage is insufficient cooling flow. Regularly check airflow and pressure in the torch (if air-cooled) or coolant (if water-cooled). If the air flow is insufficient or there is a leak, stop the machine immediately and correct the problem.
