To date, the advances in plasma technology have not been abrupt, industry shaking events. Instead, there has been a steady progression in the capabilities, quality and value of the plasma cutting process.

The first industrial plasma systems introduced by Union Carbide almost 50 years ago were large and expensive to purchase and operate, but could cut virtually any metal up to 10 in. thick at relatively high speeds.

The original conventional plasma systems could cut metal at high speeds but often required follow-on manufacturing processes to prepare the cut edge before welding or fabrication.  Cut quality considerations that have spurred innovation are the bevel of the cut face, top edge rounding, dross formation and the infusion of nitrates in the cut face which can cause weld porosity problems. The quest for cut quality continues to be a primary focus for plasma system manufacturers today.

The cost of plasma cutting has also  benefited from technological advances.  Throughout the 1950s and 1960s, only the largest companies could justify the expense of purchasing and operating a plasma cutting system. With the introduction of low amperage air cutting and the improvements made to the life of the plasma torch consumables plasma cutting has become affordable to the smallest fabrication shop and hobbyist.

Advances in manufacturing technology have allowed plasma system manufacturers to produce better torches, electrodes and nozzles.

The designs are subjected to computer modeling and simulation to help prove the designs before ever putting tool to metal.

The parts are produced on high tolerance CNC machines and subjected to rigorous in-process controls and testing to ensure they meet today's stringent design specifications. As a result of these high levels of design and manufacturing process control,  today's plasma torches produce more consistent, predictable cuts and the plasma consumables last significantly longer than those produced just a few years ago. 

The increased durability and endurance of the electrodes and nozzles have allowed plasma process engineers to push the operating limits by using higher torch chamber pressures, higher arc densities and higher plasma gas velocities to produce longer, straighter plasma cuts and faster cutting speeds.

The longer consumable life and faster cutting speeds continue to reduce the cost of a plasma cut part.

Advances in computer and electronic technology and in process control automation are being implemented within the plasma system as well. The use of high power transistors and microcontrollers has made plasma power supplies faster and more efficient; their output current is smoother and more tightly controlled. 

Electronic proportional valves, pressure and flow transducers and microcontroller boards are being utilized in plasma flow control units to select, mix, regulate and control the gases delivered to the torch at each phase of the cutting process.

The use of these intelligent controls allow the automated setup and configuration of a very large number of process variables.

Tying all of these intelligent modules together and allowing them to communicate with external systems are high speed, industrial communication systems.

A single process control unit communicates with and coordinates the functions of the power supply and flow control unit. The process control unit can also communicate externally to a CNC or to an automated shop-data collection system.  Many of these advances were pioneered initially to allow for high quality precision plasma cutting, but today are finding common usage in a wide range of plasma cutting systems and applications.

Just as the multi-purpose office computer has replaced most purpose-built equipment in our offices, plasma systems will feature multi-purpose torches, flow controls and power supplies that will be easily customized or configured for a particular cutting application.

Almost as easily as you configure your office PC from a word processing application, to an accounting spreadsheet, to an internet browser; you will be able to configure your plasma system to perform multiple fabrication roles. 

The automated plasma systems in development today will allow the plasma system to quickly reconfigure to meet the immediate particular needs of the manufacturer. 

A single system will be able to perform standard, low-cost plasma cuts, high-quality precision cuts, high-speed cutting and very thick plate severing operations with only the change of the torch consumables. 

These multifunctional systems will be able to cover the broad range of plasma cutting and marking applications that today often require separate purpose-built systems. 

This article was written by Ruben Chico, senior product manager, mechanized plasma, ESAB Welding & Cutting Products, ESAB North America, Florence, SC.

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