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3-D plasma cutting in a 2-D world

A fabricator devises a way to speed up production of structural steel using its plasma cutting table

Figure 1
Can you cut a 3-D shape on this type of table that was designed for processing 2-D material? R.J. Cyr Co. Inc. figured out a way.

Metal fabricating expertise doesn’t have to be confined to part design. Sometimes that expertise comes in handy when it’s time to simply produce parts.

R.J. Cyr Co. Inc., Maidstone, Ont., is regularly challenged with that scenario. The company is heavily engaged in the production of fabrications for industrial settings. This work might range from stairs used to walk over an assembly line to conveyors of all shapes and sizes.

Over the Christmas holiday last year, R.J. Cyr was tasked with a job that was simple in nature, but ended up being complex in scope. It had to produce 108 sections of guarding for a Canadian automotive assembly plant. Each section of the guarding had a pretty significant structural component: 6-inch channel perimeters and 4-in. channel in the stringers.

“The real challenge was all of the copes,” said Randy Cyr, company president and general manager. “We did the math, and we had 108 of these things times six beams times four corners. We had hundreds of these things to do, and we couldn’t be doing this manually.

“And our ironworker really doesn’t like to punch out corners on a channel,” Cyr added.

That’s when the brainstorming meeting was called. The machine operators, the estimators, the plant manager, and Cyr all got together to figure out a better way to tackle this fabrication project. There had to be some sort of automated approach.

Someone suggested using the plasma cutting table, but the idea was quickly shot down. You couldn’t cut a 3-D structural piece on a table designed for cutting flat parts.

Or could you?

A call to the maker of the plasma cutting table, Messer Cutting Systems, soon followed. R.J. Cyr was about to enter the world of 3-D cutting on a 2-D cutting table (see Figure 1).

Making the Right Changes

Dennis Serran, an R.J. Cyr project manager, made the call to the machine tool representative and found out that this type of request was a first. They weren’t put off, however, because they were just as interested as the R.J. Cyr team was in how this might be done, according to Serran.

Figure 2
Not only did the plasma cutting head deliver efficient cutting of the structural steel beam, it also cut it cleanly, eliminating the need for any postprocess cleanup.

“The applications engineer wouldn’t let me go until it worked,” Serran said.

The easy decision was treating the 3-D structural steel beam as a 2-D cutting job. A fixture was created so that the beams could be placed directly in the correct position for cutting. (The fixture had a stop on it, so when the operator placed the channel into the fixture, it stopped where it needed to. It created the zero mark for the torch head alignment.) After the first corner cut was completed in the flat position, the beam could be rotated manually 180 degrees to accommodate the next cut.

The real challenge was producing the 0.625-in. radius that the engineers called for on the prints.

“The engineers like to see that radius on those cope cutouts because if you put a square corner in there, which a lot of people do, that leads to a possible fracture point,” Serran said.

That’s where Serran needed machine programming assistance.

“You have to kind of fool the machine into cutting varying thicknesses of materials,” Serran said. “For example, first you start out cutting 3⁄16ths, and then as you make the turn, you have to fool it into thinking that it’s going through 2 in. because now it’s going through the leg.”

Instead of preparing programming for each different length of channel, Messer engineers only had to create cutting programs for each of the thicknesses in the channel flat part sections. The Messer EdgeMax with HPR400XD plasma cutting system was ready to enter a new dimension in cutting.

Serran estimated that the company completed about 1,000 copes over several days. Because the copes were done on a CNC machine, R.J. Cyr didn’t have to worry about postcut cleanup (see Figure 2).

The use of the plasma cutting table also allowed the company to assign a less experienced fabricator to the job. If it had been a manual task, a seasoned fabricating professional would have been needed to match the quality cuts of the plasma table, taking him away from more complex—and higher-margin—work.

Maximizing the Machine

With this new approach to cutting structural steel segments, R.J. Cyr can approach traditional cutting jobs from a new perspective.

“Once you do this type of thing, you wonder if you could do something else similarly,” Serran said.

For instance, he said they were quoting a job that called for a round hole in the channel to accommodate a piece of pipe that goes through the beam. If it can do one hole, then why couldn’t the plasma cutting machine accommodate two or three holes? The precision and quickness of the equipment open the door to more complex work that can be done in much tighter time frames.

About the Author
The Fabricator

Dan Davis

Editor-in-Chief

2135 Point Blvd.

Elgin, IL 60123

815-227-8281

Dan Davis is editor-in-chief of The Fabricator, the industry's most widely circulated metal fabricating magazine, and its sister publications, The Tube & Pipe Journal and The Welder. He has been with the publications since April 2002.