Did you know that the key to getting top-notch cuts from your CNC plasma machine is a steady arc? If that arc starts acting up, you’ll run into some serious issues.
We’re talking uneven cuts, nasty edges, and a control system that’s not pulling its weight. To make matters worse, you’ll swap out nozzles and electrodes more than you’d like.
Don’t sweat it, though – we’ve got some solutions to get that arc back on track.
Improve Contact Between the Workpiece and Ground Wire
Proper grounding is a must for getting the most out of your CNC machine. If your workpiece isn’t grounded correctly, the connection between the ground wire and the workpiece will be weak. And that’s not good.
Make sure you’re using specialized grounding tools to check for insulation that could weaken the connection. Also, steer clear of old or worn-out ground wires, or you’ll be setting yourself up for trouble.
Balance the Air Pressure
Too much or too little air pressure can also cause problems for the plasma arc. If the air pressure is high, the excessive airflow will disperse the arc, reducing its concentration and intensity and ultimately weakening its cutting power. Not good.
But what causes high air pressure? It could be a failed relief valve, improper input air conditioning, or a regulator set too high.
To solve the problem, check your air compressor pressure and ensure everything between it and the filter relief valve is working correctly. If your air filter relief valve isn’t responding to adjustments, it’s time for a replacement.
Coming over to low air pressure, if your working pressure is significantly too low, your cutting quality will suffer. Typically, low-pressure results in a weakened plasma arc, unwanted material buildup, and incomplete cuts.
Common causes of low air pressure include low-pressure adjustment, an obstructed air channel, or oil pollution in the electromagnetic valve.
You can address this issue by inspecting your compressor’s output pressure, adjusting your air conditioning valve, and performing regular maintenance on your air filter relief valve to keep the air clean and oil-free.
And if you deem it necessary, replace the electromagnetic valve or air tube according to the provided instructions.
Avoid Going Overboard with the O-ring Lubricant
It’s easy to think that more is always better, but when it comes to applying O-ring lubricant or anti-spatter compounds on shields, it’s important to use just enough to get the job done. Overdoing it with these materials can lead to contamination of the torch and ultimately result in its premature failure.
Another common mistake to avoid is applying grease or other lubricants to torches. They simply don’t need it, and doing so can cause more harm than good. Lubricants can even conduct electricity and create issues with the torch.
Be mindful of excess compounds as well, as they can clog up swirl rings and attract metal dust, leading to potential arcing problems. So, remember to use only as much as necessary to keep your torch running smoothly.
Be Mindful of the Spark Generator
When it comes to using a CNC plasma cutting machine made by a leading CNC plasma table manufacturer, igniting the plasma arc is the first and most important step. This process is initiated by the high-frequency oscillator, which triggers a discharge between the electrode and the nozzle’s inner wall. The gas is partially ionized by the discharge, and a small arc is formed. The spark generator powers this function, but it only works for a short period of one-half to one second.
If the arc fails to break automatically, it may be due to an imbalance in the components of the control circuit board or an improperly set gap between the spark generator’s discharge electrode.
To resolve this issue, it is important to frequently check the discharge electrode of the spark generator to ensure its surface remains smooth. Additionally, timely adjustments to the discharge electrode gap (0.8 ~ 1.2mm) and replacement of the control panel, if necessary, can help address this problem.
Prevent Arc Stretching and Maintain Correct Standoff
Arc stretching is something you’ll want to avoid when using your plasma cutting machine. Why? Because if the arc has to stretch to reach the metal, the consumable parts will wear out faster than usual. That’s why it’s better to use edge starts whenever possible rather than pierce starts.
Another thing you should do is to start the plasma arc with the nozzle orifice centered over the edge of the workpiece. This will help prevent arc stretching and extend the life of your consumables.
For pierce starts, make sure to set the standoff to twice the height used for cutting or to the maximum height that will still allow for arc transfer. Timing is also important when it comes to avoiding arc stretching. You’ll want to ensure that the arc-off signal is appropriately timed to prevent any stretching at the end of the cut.
It’s also important to maintain the correct standoff when using your CNC plasma table machine. The standoff should be determined by the thickness of the material being cut. Keeping the correct standoff will help ensure that the arc flows correctly and prevent damage to the torch or the workpiece.
If you’re using a hand-held cutter, you may find that standoff devices can be helpful. For mechanized systems, you can set or maintain the standoff height manually or by using automatic height control.
The Usual Suspects
When a plasma cutter fails to arc, it’s important to investigate the root cause of the problem before attempting any fixes. Common culprits include insufficient air pressure, faulty power supply components, and an improperly assembled torch.
However, users must also consider factors such as cutting speed, torch angle, and their own skill level in operating the plasma cutter. By addressing all potential issues and taking the necessary steps to rectify them, users can ensure a stable and efficient plasma arc for their cutting needs.