Since the process was developed in the 50s by Union Carbide, plasma cutting has indeed come a very long way. Today, it is among the most popular metal cutting processes used by several industries. In the early years, plasma cutters were quite rudimentary and were used to cut aluminium and stainless-steel plates of 0.5” to 6” thickness and plasma cutting was the best method to cut non-ferrous plates.
Through the 60s, the plasma cutting process went through several improvements and engineers worked on the improvement of cut quality and increased electrode and nozzle life of the plasma torch. This led to plasma cutting being used for cutting at very high speeds and cutting complex patterns in non-ferrous materials.
The water injection process was introduced in 1968, where pure water was injected around the plasma jet in order to constrict the plasma arc. This helped to increase the energy density and improved the cooling of the nozzle and resulted in high-quality cuts, faster cutting speeds and also the capability to cut carbon steel 4-6 times faster as compared to oxyfuel cutting.
At this time, XY motion control systems came into existence with microprocessor control technology being used to control the cutting systems resulting in improved accuracy, faster cutting speeds and higher productivity and automation levels.
In the 70s, plasma cutting replaced oxyfuel cutting for several cutting applications. Although plasma cutting was able to cut steel of thicknesses more than 1 inch, oxyfuel cutting was still a cheaper alternative for cutting heavy steel plate.
Recent Technology Developments
The recent developments in plasma cutting technology have been very rapid. HD plasma cutting machines with CNC systems have revolutionised the plasma cutting industry. Now, the CNC machines have touchscreen capability thus minimising the use of buttons for operation. This has made the job of the operator very easy by automating the height control, consumable adjustments, etc.
The CAM software of the CNC machines has made improvements in hole cutting by deciding on the best cutting path, cutting parameters, cut-to-cut cycles, etc. The improved bevelling software has helped to simplify the operation and integration of the bevel head with the CNC cutting machines and this helps to save time spent on trial-and-error testing.
The new nozzle and gas mixing technology have helped to improve the edge quality which is now shinier, squarer and weldable. There has also been a significant improvement in cut quality, duty cycles and consumable life of air plasma systems, which are essentially portable and are meant for in-shop, handheld cutting jobs.
Now, there are small plasma cutters that are available from a 30-amp plasma cutter which can cut materials of 0.5-inch thickness to 125-amp plasma cutters which can cut up to 2.25-inch thick materials. Both the cutting systems can be used with a handheld torch or they can be mechanised for automated applications.
Plasma cutting technology has undergone several changes over the years and the advances in the cutting technology have made these cutting systems highly reliable offering improved performance, cut quality and consumable life and they are extremely easy to operate compared to the plasma cutting systems that were first created. Today, plasma cutting is a process that delivers productivity, accuracy and cost effectiveness.