Extending the life of your consumables is key if you want to optimise and increase the efficiency of your processes and reduce your operational costs. The electrodes, nozzles and shield cups of the plasma torch wear out with use, which is why they are called as consumables and knowing why and how they wear out can help you prevent the premature wear of these CNC consumables. Usually, an experienced plasma operator can identify consumable wear by the colour and sound of the arc and changes in the torch height. However, checking the cut edge quality regularly and the parts of the torch when the cut edge deteriorates is the best way to judge the torch’s condition.
Follow the Best Cutting Methods
Make sure that the gas flow is proper as if the air pressure is very high, the life of the electrode will be reduced. The nozzle life will get reduced if the air pressure is very low. Ensure that you maintain the proper distance between the plasma torch and the workpiece and when piercing, increase the distance to the maximum possible distance as the power source allows you to.
Pierce within the permissible limits and maintain the proper standoff, i.e. the distance between the torch and the workpiece which is important to both the consumables life and the quality of the cut. Maintaining the pierce height is very important, as even the slightest variations in the torch height can affect the surface of the cut. Piercing too low causes the molten metal to be spattered onto the shield and nozzle and causes the parts to be damaged and also problems with the cut quality.
Avoid touching the metal with the torch while piercing or dragging it along the surface when cutting, as this can cause the arc to be snuffed and can destroy the nozzle, electrode, gas swirler and also the plasma torch. It is recommended that you pierce at 1.5-2 times the cut height, as this helps to protect the parts and the torch from getting damaged.
Using the proper nozzle and the correct amperage while cutting can help to prolong parts life and also achieve the best cut quality. The plasma gas must be kept dry and clean and the correct airflow and pressure must be maintained as per the recommended levels.
The cutting should be done at the correct speed as too slow or fast cutting will result in cut quality issues. Slow cutting speed will cause the kerf to be widened, accumulation of spatter at the top and dross along the bottom of the cut pieces. Too fast cutting speed will cause the arc to lag and cause a narrow kerf, bevelled edge and a hard dross bead at the bottom edge of the workpiece. Maintaining the correct cutting speed will minimise the production of dross and you will also get clean edges that do not require secondary work.
Always start the cutting at the edge and the arc with the orifice of the nozzle placed directly over the workpiece. Avoid stretching the arc as this can cause the plasma to cut into the nozzle’s side wall. Avoid creating unnecessary pilot arcs, ensure that the slag is removed from the shield regularly and purge the plasma torch after changing the consumables in order to blow out any moisture.
Ensure that the plasma torch and the consumables are clean and any metal dust, dirt, and lubricant must be removed. Clean the oxides from the nozzle and the electrode periodically as the build-up of oxides reduces the consumable life and also disrupts the flow of gas.
Check the hose cables and air filters for leaks and every week drain and clean the air filters properly. The pressure and flow of the coolant and gas should be checked daily, as insufficient flow will prevent the consumables from being cooled and reduce the part life. Also, clogged filters can cause the improper flow of water and result in torch failure.
The proper upkeep and regular maintenance of the plasma torch and the various consumables will ensure that your plasma cutter will give you long-lasting reliable service for several years without any issues and reduce downtime thereby ensuring that the productivity of your business is enhanced.