Plasma cutting technology has advanced to the point that it has forced metal fabricators to rethink its usage. High-definition plasma cutting provides a squarer edge-cut than previous generations of the technology. On 0.25-in. mild steel, plasma torches can reach cutting speeds of more than 100 IPM. Plasma systems also can deliver bolt-ready holes that help to minimize secondary machining activities once the plate parts leave the table.
Even with those advancements, plasma cutting technology manufacturers continue to put money into research and development. Laser cutting systems are becoming more powerful and cost-effective, so more shops are using them to cut thicker materials more regularly. Waterjets remain a suitable way to cut very thick materials, and steps have been taken to improve productivity on the machines. That leaves plasma cutting technology companies trying to defend their turf as the cutting method of choice for heavy-duty fab shops and service centers.
These companies have used the time wisely. Thinking of a plasma cutting table as a tool to process only 0.25- to 2-in. mild steel does not reflect the current reality of the technology, especially as it relates to cutting thick nonferrous materials. Fabricators and service centers would be wise to ask themselves what plasma cutting systems of today can do—and maybe what they might be capable of tomorrow. Here are some questions that can help plate processors understand what plasma cutting technology has to offer.
Does a plate processor have to invest in a powerful plasma power source just to cut thick specialty material, such as nonferrous metal between 2 and 6 in.?
Fab shops and service centers are used to processing thick materials, and usually the tools of the trade are familiar. Two-hundred, 300-, and 400-amp plasma systems are used to cut ferrous and nonferrous material up to 2 in. Oxyfuel systems make the most sense for ferrous material thicker than 2 in. because the rapid oxidation process, in which the steel surface is heated up to approximately 1,800 degrees F and then hit with an oxygen stream to blow away the slag, produces a square cut, leaves a smooth cut surface, and creates little to no slag on the bottom edge. (On its own, oxyfuel would have a difficult time cutting nonferrous metal. For example, in stainless steel, the resulting oxide created during the cutting process has a higher melting point than stainless steel, which means no material is being removed. Technically, oxyfuel could be used to cut nonferrous, but it involves injecting an iron-rich powder into the cutting zone. The iron powder combusts, increasing the reaction temperature, creating a fluidization of the oxidized layer and making it possible to remove material in the cut zone. This powder cutting is used on a very limited basis.) Waterjets are popular because they can cut very thick metals, up to 1 ft., but they are relatively slow compared to other cutting methods.