Why does the CNC plasma cutting machine break the arc when cutting?

Why does the CNC plasma cutting machine break the arc when cutting?

CNC plasma cutting machine has the advantages of simple operation, high cutting precision, high work efficiency, and low labor intensity. It is very popular in cutting a variety of metals and small size workpieces. However, for users who are exposed to CNC plasma cutting machines for the first time, arc breaking has become a common and headache problem, to help everyone solve this problem. Huafei CNC summarized the reasons and solutions for the arc breaking of CNC plasma cutting machine, hoping to help users operate.

The air pressure is not stable enough

The working pressure of plasma cutting is too high or too low will affect the cutting effect. If the working pressure is far below the required pressure. This will cause the discharge speed of the plasma arc to decrease, and the input air flow rate is less than the specified value. Can not form high-energy, high-speed plasma arc. Causes poor incision quality, impenetrable incision, and incision tumor. If the input air pressure exceeds 0.45MPa, the working air pressure is too high. After the ion arc is formed, the excessive airflow will blow away the concentrated arc column, disperse the arc column energy, and weaken the cutting strength of the plasma arc.

Burning torch nozzle and electrode

Because of the improper installation of the nozzle, the CNC plasma cutting machine broke the arc. For example, if the thread is not tightened, the gears of the equipment are not adjusted properly, the cutting torch that requires water cooling is working, the cooling water is not passed as required, and the frequent arcing will cause premature damage to the nozzle.
Solution: Correctly adjust the gears of the equipment according to the technical requirements of cutting the workpiece. Check whether the torch nozzle is installed firmly. Need to connect the cooling water nozzle to make the cooling water circulate. When cutting, adjust the distance between the cutting torch and the workpiece according to the thickness of the workpiece.

Input AC voltage is too low

There are large-scale electrical facilities at the use site of the CNC plasma cutting machine, and the failure of the internal main circuit components of the cutting machine will cause the input AC voltage to be too low and cause the arc to break.
Solution: Check whether the power grid connected to the CNC plasma cutting machine has sufficient carrying capacity. Whether the power cord specifications meet the requirements. The installation location of the CNC plasma cutting machine should be far away from large-scale electrical equipment and places with frequent electrical interference. During use, clean the dust in the cutting machine and the dirt on the components regularly, and check whether the wires are aging.

Poor contact between the ground wire and the workpiece

Grounding is an essential preparation before cutting. If a dedicated grounding tool is not used, insulation on the surface of the workpiece, and long-term use of a ground wire with serious aging, etc., the ground wire will not contact the workpiece badly, and the arc will be broken.
Solution: You need to use professional grounding tools, and check whether there is any insulation affecting the ground wire and the surface of the workpiece, and avoid using aging ground wires.

The spark generator cannot automatically break the arc

When the CNC plasma cutting machine is working, the plasma arc must first be ignited. The high-frequency oscillator excites the gas between the electrode and the inner wall of the nozzle to generate a high-frequency discharge, which partially ionizes the gas to form a small arc. The small arc acts on the compressed air and ejects from the nozzle to ignite the plasma arc. This is the main task of the spark generator. Under normal circumstances, the working time of the spark generator is only 0.5~1s. The reason for the inability to automatically cut off the arc is generally that the control circuit board components are out of adjustment and the discharge electrode gap of the spark generator is inappropriate.
Solution: It is necessary to check the discharge electrode of the spark generator frequently to keep its surface level. Adjust the discharge electrode gap of the spark generator (0.8~1.2mm) in time, and replace the control board if necessary.

In addition to the above objective reasons, the reason for the arc breaking of the CNC plasma cutting machine is also related to the user. If the user is not familiar with the equipment, the operation level is low or the operation is improper, it will cause the arc to be broken. This requires the user to fully understand the CNC plasma cutting machine before starting the cutting operation.

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