Once you have selected the plasma cutting system that is right for your business, there are a few steps that will allow you to get the best possible cut quality from your plasma cutter.
Setting up Process
Before you actually start using the plasma cutter, check the compressed air supply and ensure that it does not contain any oil or water. If you notice any black marks on the workpiece or if the consumables wear quickly, this may indicate that there is air contamination. Check the air pressure and if the electrode and nozzle are positioned properly.
Before you start, ensure that you read the operation manual of the plasma cutter and understand it properly. While using the plasma cutter, ensure that you wear long sleeved clothes, gloves, welding shield or dark goggles to protect yourself from the molten metal generated during the cutting process and also protect your eyes from the plasma arc.
Avoid piercing the metal perpendicular to the workpiece, as this causes the molten metal to be blown back into the plasma torch. Instead, pierce at a 30o angle from the vertical and 60o from the horizontal and then rotate the torch to the vertical position, as this allows the molten metal to be blown away from the plasma torch.
Avoid Touching the Nozzle to the Workpiece
When you are making use of an electric current of 45 amps or more, avoid touching the nozzle to the workpiece, as this will cause double arcing through the nozzle and reduce the life of the nozzle drastically. Dragging the plasma torch against the metal template also causes double arcing and will result in premature wear of the nozzle.
Use a Drag Cup
It is a good idea to use a drag cup over the nozzle and allow the plasma torch to rest on the workpiece to ensure that you get a steady cut.
Move at the Correct Speed
When you cut at the right speed, the molten metal will blow out of the metal at a 15-20o angle. If the speed is too slow, then a slow speed dross will be created, which results in the molten metal being accumulated at the bottom edge of the cut. When you move too fast, the top surface develops a high-speed dross as the arc does not pass via the metal fully. Also, cutting too slow or too fast results in a low-quality cut.
Set the Current to Maximum
When you begin cutting, set the current to maximum output and then turn it down as required, as this gives you better results, except when you are precision cutting or you need to maintain a small kerf.
Minimise the Pilot Arc Time
Minimise the time of the pilot arc as this causes the consumables to wear out more quickly. Position the torch at the edge of the workpiece before you start the arc so that you can begin cutting immediately.
Maintain Constant Distance
Ideally, maintain a distance of around 3/16 – 1/8-inch between the nozzle and the workpiece and avoid moving the plasma torch up and down.
Cut in the Best Direction
Always cut in the direction that will give you the best cuts. For instance, if you plan to keep the circular piece when cutting in a circle, move the torch in the clockwise direction and if you want to keep the piece from which you have cut the circular piece, then cut in the anticlockwise direction. When you push the plasma torch away, you will get a better-quality, square edged cut on the right-hand side of the metal.
Plasma cutting has many advantages and can provide higher-quality cuts and faster cutting. Once you find the right plasma cutting system for your business and you learn the tips and tricks, you are all set to begin cutting.