Plasma cutting service shop buys time by doubling cut speed

“Time is the most expensive commodity in the world, so if you have the chance to buy time, do it,” says Zoran Gjerovski, who upgraded to an integrated automated plasma system from Thermal Dynamics to more than double productivity.

Is time a huge expense or an extremely valuable commodity? It’s both, according to Zoran Gjerovski, owner of Design AG, a plasma cutting service and fabrication shop in Mississauga, Ont.

“Time is the most expensive commodity in the world, so if you have the chance to buy time, do it,” said Gjerovski.

To buy more time for himself, Gjerovski doubled his cutting speed by upgrading to a high-definition plasma cutting table.

Running Fast

Gjerovski immigrated to Canada from what is now North Macedonia, one of the successor states to the former Yugoslavia. Before starting Design AG, he worked as an inside sales representative for a Toronto-area steel service company and realized that there was an unmet need in the market.

“Customers kept saying, ‘Laser cutting is more expensive than plasma cutting, and we need it cheap, cheap, cheap — do you know anyone with a plasma cutter?’ By the time five customers asked the same question, I got the point: It’s time to open a plasma cutting shop,” said Gjerovski.

The name Design AG comes from his teenage daughter’s initials and his belief that she could design her future to be whatever she wanted by making smart choices.

In 2015 Gjerovski opened the doors to his 3,000-sq.-ft. shop, located in an industrial building on the western edge of Toronto’s Pearson International Airport. He started by acquiring a used cutting table with a 130-amp plasma machine and built a customer base through good service and his witty personality. Most of his business comes from cutting steel plate for structural steel applications, as well as the occasional ornamental items such as figures of people, animals, and railing panels. While business was good, he knew it could be better.

“I have a good customer base, and I wanted to increase productivity without hiring new employees,” said Gjerovski. “Time spent cutting is worth much more than time spent doing other things. Having an older, slower machine is no good to me. A fast machine and better system would offer so many benefits.”

Design AG cuts 1/8- to 1-in.-thick material, with the occasional need for up to 1½-in. steel, as well as thin plate. For these applications, an older 130-amp power source is undersized. Recognizing this, Gjerovski reached out to Nolan Venne, an account manager with Thermal Dynamics Automation.

A selection of the steel components Design AG cuts with its 300-amp plasma system. Note the quality of the holes.

For the material thicknesses in the range Design AG wants to cut, Venne recommended the 300-amp Ultra-Cut® XT, which can pierce plate up 1½ in. and cut ½-in. steel at 140 IPM (see cutting speed chart).

“The cutting speeds are exactly what they are listed as in the spec sheet,” confirmed Gjerovski. “They’re more than double the speeds of my previous machine, so I cut my cutting time in half.”

The table, a ProSteel HD Hi-Def series 6- by 12-ft. model from Fab-Cut Systems Inc. (Kingston, Ont.), has an integrated system from Thermal Dynamics. Key components, beyond the plasma power source, include the iCNC® Performance controller, automatic gas control, torch lifter, and the machine’s motors and drives.

Since acquiring the new system in September 2018, Gjerovski said the profit generated already has him looking at acquiring a second table by the end of 2020.

“If I make X amount of money now, I know another machine will help me increase productivity by at least two or two and a half times that,” he said. “My biggest issue will be hiring the right people to run them.”

Quality Cuts

Gjerovski believes his customers count on two things: service and quality.

Cut quality has a technical definition, which includes squareness of the cut face and appearance and condition of the cut surface (see sidebar story). Except when codes require mechanical edge preparation to eliminate any potential nitride inclusion, a high-precision plasma part is ready for the next fabrication step. Gjerovski characterizes quality a bit more easily.

“Assessing quality is very simple,” he said. “If you have fewer customer complaint calls, you have good quality. When customers ask, ‘Why did you cut it this way?’ it means you’re not doing a good job. If you don’t have quality, you are out of the game very quickly.”

To produce a quality cut, the automated plasma process requires millisecond timing and micron tolerances over about a dozen variables, notably torch height, amperage, gas pressure, and cutting speed. It’s a lot like a symphony: Every instrument has to play perfectly together or the result sounds cacophonic. Using an integrated system with all critical elements from a single supplier ensures that all components work harmoniously.

Controller Time Savings

Many small shops face a dilemma when evaluating using a PC for a controller (along with third-party software) or a controller designed specifically for automated plasma cutting. While the first choice may save a few dollars on upfront costs, controllers provide a number of functions that enable Gjerovski to save time in myriad ways.

For example, the iCNC Performance automatically sets and dynamically controls all variables and components through a built-in process parameter database, minimizing programming time.

Using a touchscreen interface, Gjerovski enters the material type, thickness, and plasma/shield gas choices (O2/air). After nesting the plate (another automated function), he can choose a “hole optimization” function (also via the touchscreen) and the CNC will automatically adjust variables to cut bolt-ready holes. Alternatively, he can program the system to cut at the fastest speeds possible for applications with looser tolerances.

“Some of my structural customers need holes to be cut very neatly and precisely,” said Gjerovski. “With the [controller], you can control the speed separately. With the holes that aren’t as important, you can cut faster, and you can cut slower for the ones that you need a perfect cut. My customers only want to pay for what they need.”

While the controller enables loading of parts files wirelessly via USB or over an Ethernet, Gjerovski receives orders in various – and sometimes archaic — ways.

“In the structural steel business, I often get a PDF of a drawing, but I get texts and phone orders too,” he said. “The last order I got was a guy who called and said, ‘I need 25 square plates made from 3/8-in. steel; they’re 12 in. by 12 in. with four holes for ½-in. bolts that have to be 1½ in. off the edge.’ That was enough for me. Using the parts shape library in the controller, I can design exactly what he asked for. I don’t have to draw every single plate on my computer,” said Gjerovski.

After the part is designed, a plate nesting function automatically organizes the nest to minimize scrap and optimize speed.

The controller also offers a function called a bridge tool that automatically assigns cut segments between parts. It bridges the gaps for continuous cutting, which reduces the number of pierces. Arc starts - and especially piercing - create the majority of consumables wear. In a lot of cases, it’s also faster to keep cutting than to stop and restart. The bridge tool can improve productivity by up to 40 per cent depending on the nest.

Circling Back

Upgrading to an integrated system enables owner Zoran Gjerovski (at controller) to achieve higher productivity and quality on a wider range of material thicknesses.

For a company without engineering resources, using a controller like this is like having a plasma cutting expert and engineer inside the box.

Plasma controllers contain design optimization functions, programming skills, and cutting techniques that would normally take 20 years of experience to acquir. The controller can compress learning from years to a few weeks.

“After I figured out that the most expensive thing is time, I try to make the best use of it,” Gjerovski said. “I use almost everything that’s available in the controller, and there are so many possibilities. Coupled with double the cutting speed, that sold me on a new system even more.”

Dirk Ott, is vice-president, global mechanized plasma systems, Thermal Dynamics, 2800 Airport Rd, Denton, Texas, 76207, 940-381-1329, www.thermal-dynamics.com.

Cut Quality

Use the following characteristics to evaluate cut quality. Ask your plasma system provider for cut samples that also include cut time and estimated cut cost per part.

• Accuracy. High-precision plasma can achieve a cut accuracy of ± 0.01 to 0.05 in.
• Kerf width. Maintained through long-life consumables, kerf (or cut) width is a function tip orifice size, current setting and torch height. It should be narrow (+0.05 in.) and consistent.
• Surface. A smooth surface free of dross and nitride contamination.
• Cut surface bevel angle. The proper torch height control produces the smallest bevel angle, defined as 0 to 3 degrees for high-precision plasma.
• Top edge rounding. Proper torch height control minimizes top edge rounding, which is caused by the heat of the plasma arc at the top surface of the cut.
• Top spatter. Minimal spatter is produced with the proper cutting speed and torch height.
• Bottom dross. Dross is minimized with the proper cutting speed; any dross will remove easily.
• Mechanical properties. Welded comp