At EZCut CNC, some of our cutting system components come standard and are the same across the board, regardless of the system you select, such as ATHC (automatic torch height control), gantry, etc. But other components, such as the plasma cutter, can be selected based on your metal fabrication shop’s specific needs. Different plasma cutters provide different features that may be more appealing, setting them apart. For instance, should you have specific material thickness cutting needs, that will help steer you in a certain direction when making a selection. A study conducted by Hypertherm and explained in The Fabricator provided an interesting look at how plasma cutter selection impacts the quality of the actual cut.
The study looked at plasma arc cutting (PAC) systems and used three different systems to prepare cut samples for metallographic analysis. The Fabricator elaborates on the findings, “This study conducted at Hypertherm characterizes thermal and chemical changes in plasma-cut stainless steel and aluminum alloys and recommends process alternatives that may improve aesthetics and cut quality to improve forming and fabricating of the materials. The systems used were water-injection PAC, conventional dual-gas PAC, and high-precision PAC. It was learned that the heat-affected zone (HAZ) is small in plasma-cut pieces, HAZ varies with speed and power, faster cutting produces less HAZ, and more heat per square inch can produce less HAZ… The plasma cutting process may be used to cut any conductive material, including carbon steels, stainless steels, aluminum, copper, brass, cast metals, and exotic alloys. Each of these materials behaves differently when subjected to the intense heating and cooling of the plasma cutting process… Cut samples ranged in thickness from 1 to 25 mm… Most of the samples were cut from sheets of 304 SS. Because 300 series stainless has an austenitic phase structure, a limited number of martensitic 410 SS samples also were analyzed for comparison… PAC processes that use a reducing plasma or shield gas, such as argon/ hydrogen or methane, produce cut edges with substantially less surface oxide that require little or no preparation before welding… The weldability of aluminum alloy cut edges made with PAC is best when surface oxides are not present. If oxidizing process gases are used in the plasma or shield, the edges may need to be ground before welding. Weldability of edges cut with reducing plasma or shield likely will be better. Because aluminum reacts so readily with oxygen, grinding still may be required to prepare the cut edge.”