Every new technology, from automobiles to televisions, goes through an evolutionary period as the product develops from the concept to finished, user-focused design. If you think back to early computers or cell phones, they bore little resemblance to today’s advanced tablets and smart phones.

The torches found on today’s plasma cutting systems are no different. The first torches were squared-off, clunky hunks of plastic that looked more like a toy hammer than high-tech cutting equipment. These torches did the trick when plasma cutting was in its infancy, but as plasma cutting and gouging evolved, it became clear that the torches needed to change to endure harsher conditions and meet a wider variety of needs.

Many people think that a plasma torch is only important as a holder for the consumables. After all, it is the consumables in the torch that make a plasma system work: the electrode carries the charge necessary to create the plasma from the power supply; the swirl ring forces the flow of the resulting plasma into a vortex; and a nozzle constricts and directs the plasma until it is focused enough for cutting. Indeed, most of the early plasma-cutting technology development centered on improving consumable design for increased ease of use and efficiency. For example, in the late 1980s the introduction of blowback torch technology eliminated the need for high-frequency starts, and the advent of shielded nozzles enabled the operator to drag the torch directly on the metal being cut (now commonly called drag-cutting.)

Operators saw immediate benefits from these technological improvements. Contact-start systems eliminated interference with other shop equipment, while drag cutting resulted in smoother, easier cuts that allowed users to follow a straight edge or template. Other improvements focused on safety, like the addition of a safety trigger to eliminate accidental torch firing and a “parts-in-place” circuit to ensure consumables were properly installed before firing the torch. The addition of quick-disconnects, like Hypertherm's one-button FastConnect^™found on the company’s newer Powermax systems, gave operators the ability to swap torches quickly or to remove the torch when transporting the power supply. But, even after all these improvements, the shape and bulk of plasma torches remained the same, limiting their use to certain applications. Making radical changes to this design would require a whole new engineering approach.

That new approach came from a group of plasma engineers at Hypertherm. The company’s engineering team was determined to re-think torch design. And they knew the best way to understand the challenges their customers faced is to watch them at work. Over the following year, engineers and product managers logged hundreds of hours on the road, talking to numerous customers during visits to scrap yards, shipyards, and any other high-use cutting environment they could find. Their goal was to find out how well current plasma torches performed in tough conditions and to see directly what operators wanted to do with plasma but couldn’t do because of design limitations.

What they heard and observed is that plasma torches, especially hand torches, take a lot of abuse. It wasn’t uncommon to see torches accidently falling off scaffolding, getting banged against metal plates, or seared by the heat of cutting and gouging. During their visits, the engineers also learned that there were a lot of jobs that operators couldn’t do with a standard 90-degree plasma hand torch or full-length mechanized torch.

Although Hypertherm engineers had plenty of ideas, they focused on three areas: creating a torch that was more robust than anything on the market; improving handle ergonomics, and at the same time improving gouging and cutting access for tight locations; and developing a shorter torch for robotic and pipe cutting applications. Everything, from the materials to the consumable design to the guts of the torch, was up for review. Hypertherm engineers spent two years prototyping torches, and then conducting heat, impact, and cut tests. With testing complete, the engineers set out to find the right material for the torch body.

The engineers wanted to stick with plastic because it is light and easily molded, but they weren’t sure exactly which plastic they would use. With hundreds of different brands and compositions to choose from, the task of narrowing down the choices was not easy. One thing that helped was the decision to turn to quantifiable measures, like the American Society for Testing and Materials (ASTM) standards for heat deflection, impact resistance, and environmental friendliness. Based on that, the team was able to concentrate on several different plastics that had the best balance of properties. Then, those choices were evaluated for actual performance before a winning plastic was selected.

“The challenge with designing plasma torches is that we are cutting metal with a plastic object,” said Jesse Roberts, one of the engineers on the project. “Ideally, the torch handle should be made of brick and rubber at the same time. A brick to take the heat and rubber to take the day-to-day abuse.”

With a material selected and the durability objective met, the next challenge was to create a torch shaped better for gouging and cutting in tight places. Oxyfuel users have long had an array of torch angles and lengths available to them. With plasma, though, the shape has traditionally been limited by the need for an internal plunger to bring the electrode into contact with the nozzle and start the arc. The plunger, and wires attached to it, needed room to move within the torch shell, restricting the choice of shapes and angles available to the engineers, and therefore limiting plasma’s usefulness for certain applications.

The solution was to work from the inside out. The engineers knew they had to figure out how to remove the plunger before they could make a meaningful change to the torch’s shape. More months of work followed until the team agreed upon a solution: an entirely new consumable design that replaced the plunger in the torch with a blowback spring in the electrode. This breakthrough technology — Spring Start^™— is what enabled Hypertherm engineers to design a nearly straight torch that angles down just 15 degrees at the tip. Additionally, engineers managed to narrow the neck of the standard hand torch for greater visibility and to change the shape so that it could be held at either a 75-degree or 90-degree angle to the plate.

Having successfully met the first two challenges (creating the most robust torch available, redesigning torches for gouging and cutting in tight places), developers concentrated on the third objective: providing mechanized plasma users with the same level of innovation and flexibility available to users of handheld plasma torches.

During their visits to plasma torch users, the Hypertherm engineers noticed that the standard-length mechanized torch was often cumbersome for pipe cutting and robotic applications. Their solution was to replace the one-piece mechanized barrel with a modular design that could convert from a long torch to a short one, easily and quickly. Users could work either with the standard 15-inch torch or remove a section from the barrel to create a 6-inch mini torch, better suited for robotic applications, pipe saddles, track burners, and other applications where the extra barrel length was a problem.

So far, the new torches, commercially available since late 2010, are getting very positive reviews. Plasma users report the straighter profile of the 15-degree torch makes cuts in corners, overhead, and in tight spots much easier. And for plasma gouging, it is especially revolutionary; it provides the user with more visibility and better control of the arc while keeping the operator’s hand away from the high heat generated by the gouging process. As Hypertherm’s Jesse Roberts notes, “a fundamental change had to take place in order to advance plasma torches to the next level of reliability and versatility.”

The change is just one step in an evolutionary process. As operators find new uses for plasma cutting and gouging, plasma engineers will continue innovating along with them.

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Paula Flanders is a technical writer and marketing specialist with Hypertherm, a designer and manufacturer of plasma cutting systems.