Kyle Kinser and Ed Werner have larger plasma cutting units. Sometimes that’s a good thing. Kinser’s automated plasma cutting system with a 10-ft.-by-30-ft. underwater cutting table and Werner’s 100-amp unit for heavy shop work tackle small projects to big parts and everything in between.
When portability counts, however, compact power is the name of the game. At their respective businesses, Kinser and Werner both rely on the same equipment: the next-generation Cutmaster 60i from Thermal Dynamics.
“Manual plasma is essential in our world because of portability and cut quality,” says Kinser, vice president of operations at Structural Strategies Inc., in Aurora, Ill., about 50 miles west of Chicago.
Structural Strategies specializes in structural steel fabrication, ornamental iron, stairs, handrails and miscellaneous metal fabrication. The company has a reputation for delivering in tight time frames – sometimes as soon as next day or the same afternoon, all facilitated by the steel inventory kept on hand.
“There’s no better tool than plasma for quick, clean cuts on stainless steel,” says Werner, owner and founder of Werner Fabrications, West Bend, Wis., about 30 miles north of Milwaukee. Werner does extensive work in the pipe, food, restaurant and dairy industries as well as HVAC, mechanical contracting and miscellaneous metal fabrication.
“The plasma cutter helps me solve unforeseen problems, such as modifying the stainless doors on a large oven used by an environmental services company,” Werner says. He explains that the doors came in at the wrong size. Instead of re-ordering and delays, “I just fixed it. I used the Cutmaster, and the customer was very happy I had the right tools.”
A plasma arc cuts through any conductive metal quickly and easily. Compared to oxyfuel torches, which are limited to carbon steel, and saws that take much more time and effort, plasma is the clear choice.
Primary power options
To operate his plasma cutter in the field, Werner prefers to connect it to the 12-kW generator power output of his engine-driven welding generator.
“I’ve got the plugs and extension cord set up for the generator,” he says. “Even if the plant has 230-V primary power, I usually don’t bother with it. I just run my extension cord to the generator and the Cutmaster works fantastic. It’s a great combination.”
Werner’s unit accepts single-phase power from 208 VAC to 480 VAC ±10 percent, another factor that appeals to him.
“I like multiple-voltage units for situations where generator power isn’t feasible and, of course, for shop work,” he says. “If I have to take the cover off to rewire the unit or search for different plug configurations, I just consider that time wasted.”
At Structural Strategies, Kinser uses the three-phase version of the Cutmaster because the 35,000-sq.-ft. commercial building is wired throughout for three-phase power to run press brakes, sheers and other heavy equipment. Drawing just 23 amps on 230 V primary and 11 amps on 480 V primary, Kinser is never worried about whether he’ll steal too much power from another piece of equipment.
While Kinser mostly uses his unit in the shop, portability is still essential for moving it around an automated table to cut up plate skeletons and throughout the shop for physical modifications to the building.
“We have other manual plasma cutters in the shop, but this one is about half the size and weight,” he says. “For a little unit, it really packs a punch. It will cut 5/8-in. steel like butter and even sever steel up to 1 1/2 in.”
Packing a punch
Next-generation inverter technology continues to increase the power-to-weight ratio of inverter-based plasma cutters as well as welders. Increasing the internal operating frequency of an inverter enables reducing the size and weight of the transformer and other components.
As a result, the newest inverters offer more power, a stronger output and/or greater duty cycle in a smaller, lighter package. Kinser’s and Werner’s units provide a 60-amp output at 50 percent duty cycle and weigh 37 lbs.
“These new units really hit a sweet spot for many fabricators,” Kinser says. “It’s great to be able to carry them up a ladder and not worry about sacrificing cutting capacity.”
Werner recently put his Cutmaster to a good test, dismantling a 6-ft.-dia.-by-12-ft.-tall stainless steel tank that needed to be cut into 2-ft. pieces so that it would fit into an environmental oven for toxic metal extraction.
“It took us 2 to 3 hours to cut up that 1/4-in. stainless,” he says. “We never hit the duty cycle, and I was surprised because that was a lot of cutting. We also encountered thicker material when cutting through old welds. It was just cutting like butter, especially with a fresh set of consumables. It was just amazing.”
Werner reports that new plasma cutter also includes a digital display that provides several LED indicators, including a consumables end-of-life indicator.
“Consumable life is really good on these units, but it helps to know when to change the electrode and tip,” he says. “The kerf width is the smallest of any plasma unit I’ve ever used, and fresh consumables keep the cut narrow.”
To enhance precision and productivity, Werner uses templates and straight edges and circle guides to help steady the torch. To modify an air filtration system, which required cutting 30 access ports through 11-gauge stainless steel, Werner created two templates. His son Cameron (who also works in the business) affixed one template while Werner cut using the other. He would then hand the torch to Cameron and move his template to the next port location while Cameron was cutting.
“With two templates and passing the torch, we completed that job in about half the time I anticipated,” he says.
Werner also appreciates the plasma cutter’s gas flow optimization function, which uses the display to provide guidance on correct gas flow rates. Previously, he just “cranked up air pressure” and started cutting, not realizing that optimized cutting performance and consumable life depended on proper gas flow rates – about 90 to 125 psi maximum.
Kinser agrees the technologies make a difference. “Today’s plasma cutters convey more information, so they’re more operator friendly,” he concludes. “Coupled with lighter weight, a compact design and a stronger cutting output, there’s a good reason to examine new technology.”