Plasma cutting is an exact science and paying attention to detail right and paying close attention to the preparation and setting up of the cutting process can go a long way in preventing a lot of problems you may encounter later on during the production process. Here are a few tips and tricks that can help your plasma cutting operators avoid some of the most common problems that they may face during plasma cutting.
Replace the Consumables Regularly
Just like you need to change the oil in your automobile to keep the engine running smoothly, which is less expensive than changing the engine itself, replacing the consumables of the plasma cutting system is a more cost-effective solution to replacing the entire torch itself. Using worn consumables can cause uncontrolled arcing and may lead to the failure of the plasma torch.
So, how can you make out if the consumables are spent? Usually, the tell-tale signs of worn consumables are the deterioration of the cut quality. Also, when inspected, if you notice oxide residue inside or you notice gouging outside or inside the nozzle, then it must be replaced.
You can check the pitting of the electrode to determine if it is worn or not. The pitting must not be deeper than 1/8th inch for nitrogen or argon and 3/32-inch for air or oxygen. If the pitting is more than these, then the electrode must be changed. And, if there are any burns, cracks in the gas swirlers or grease or dirt in the holes, then you must change the swirlers.
Proper Torch Assembly
The plasma torch must be assembled carefully and all the parts should be aligned properly and snugly. This will ensure that the electrical contact is proper and that the gas and coolant flow properly through the plasma torch. Also, the threads and the seating area of the torch must be clean.
Using the Proper Parts
The plasma gas being used and the cutting amperage essentially dictates the choice of consumables for the particular job. You can follow the operator manual that defines the type of consumables suitable for different types of cutting. If you use incorrect consumables, this can lead to decreased cut quality and reduced consumables life.
The consumables must also be run at the right amperage, which should ideally be set at 95% of the nozzle rating. Too low amperage will result in a low-quality cut and too much power will reduce the nozzle life.
Ensuring Proper Coolant and Gas Flow
The flow of the gas and coolant must be checked. The cooling of the consumables will not be proper if the flow is inadequate and this can affect the consumables life. To maintain the cutting arc, the pressure of the gas must be constant. Also, the plasma gas used must be dry and clean. Contaminated gas can result in reduced consumable life and premature plasma torch failure.
Avoid Excessive Use of Antispatter and O-Ring Lubricant
Just use sufficient lubricant to add shine to the O-rings and the shields should be removed before applying the antispatter compound. Too much of antispatter compound or O-ring lubricant can contaminate the plasma torch and lead to premature failure. You should apply any grease, lubricants, etc. to the plasma torch, as it does not require any lubrication.
Use the Torch Correctly
Avoid any torch collision as crashes and tip-ups can damage the plasma torch irreparably. The THS (torch height sensors) protect the torch from workpiece crashes by correcting the height. Breakaway mounting devices also help to prevent any damage to the plasma torch in the case of a collision.
The consumables will fail if the plasma arc needs to stretch to reach the workpiece. So, it is always a good idea to use edge starts instead of pierce starts and the arc must be started with the orifice of the nozzle placed directly over the workpiece’s edge.
Always maintain the correct standoff, which is essentially determined by the material thickness. If the standoff is too high or very low, it can damage the workpiece or the plasma torch.
Clean the Plasma Torch Regularly
You must keep the plasma torch clean and watch out for any contamination. The seating areas of the electrode, nozzle and the torch threads must be cleaned regularly.
You can save several hours and reduce operational expenses by operating the plasma cutting system properly. This also results in longer consumable life and high cut quality and also involves lesser time in cleaning and finishing the parts before they go to the next stage of the manufacturing process.