Cutting's Current State: Laser cutting on the bleeding edge

Editor's note: This is the second part of our four-part Cutting's Current State series to commemorate our 50th anniversary. Check out Part I, Part III, and Part IV.

When rookies begin in the laser cutting department at Cupples’ J&J Company Inc., they usually find themselves offloading cut parts out of a nest, right after it comes off the laser. It’s a common starting point for many who begin their working lives at a typical metal fabrication job shop, especially the small ones—maybe a dozen employees, less than $5 million in annual revenue—without the automated blanking systems more common in larger operations.

Thing is, Cupples’ J&J isn’t small. In fact, by custom fabrication standards it’s one of the largest operations in the country, with 340 employees and annual revenue surpassing $63 million. Between a plant in Jackson and another in Dyersburg, Tenn., it has 19 laser cutting machines, including a few of the most powerful this side of the Atlantic. It has more than 35 press brakes, comprehensive machining capabilities, a large welding operation (both manual and 25 robotic cells), the works. Yet you won’t see an automated tower feeding sheets or storing cut parts anywhere. The shop does have one laser with automated loading/unloading, but that’s for scratch-free handling, not increased throughput.

“People tell us that to grow, we’ve got to automate everything,” said Jeff Cupples, vice president of estimating and engineering. “Well, somehow, some way, we’ve managed without it. We kept thinking, ‘We’re eventually going to have to use automation.’ But our customer base pretty much said we didn’t need to. We have 99% on-time delivery. And we have no debt. We own every machine we have, and we pay cash for the new machines we buy. Somehow in this crazy world, we’ve found our niche.”

The operation continues to grow, proof that there is no single “right way” to run a laser cutting department and, for that matter, manage a broader custom fabrication operation (and in Cupples’ case, a large machine shop as well).

To celebrate The FABRICATOR magazine’s 50th year, we’re taking a look at laser cutting’s current state, dissecting the operation at several prominent fabricators across the country. The magazine and laser cutting grew up together. The publication’s coverage of sheet metal laser cutting goes all the way back to 1974. Through the years it has documented the laser cutting machine’s rise from obscure novelty and a potential replacement of “flex tool” punch press work to industry dominance. To be sure, Cupples’ J&J wouldn’t be the operation it is today without it.

The Optimized Nest

Cupples’ takes a “mini-factory” approach to its cutting and bending operations, governed by its customer mix. The company has a handful of very large customers that have high capacity requirements, usually enough repeating parts to fill an entire mini-factory. Cupples’ remains a job shop, so resource-sharing abounds. If one mini-factory has available capacity, planners shift work to suit. And one mini-factory remains dedicated to short runs and high product mixes.

Each mini-factory is staffed with a group of people very familiar with a group of products, either from a single customer or a handful of customers. “But we’re flexible,” Cupples said, adding that if capacity demands change, people move between mini-factories as needed.

The staff isn’t just familiar with a group of parts in a cursory sense, either. They know which material grade from which mill suits those parts best, and which lasers work best.

The mini-factory approach guides career paths, and training starts by shadowing veteran personnel—not sitting in front of a computer, looking at a nest layout, but standing by the laser shuttle table itself, offloading parts.

One might think that offloading parts would be a good way to lose new people in a hurry. But that doesn’t happen at Cupples’, mainly because operators learn the importance of a smooth offload process. If operators can remove, stack, and send parts downstream to the next operation quickly, they know that all the operational variables around them are working as they should. Each machine has a swing-arm loader with extended reach. And at every machine, people can access the shuttle table on both sides, able to remove and sort parts as quickly as possible.

Shaking and breaking is a rarity. “We don’t like to tab [parts into nests],” Cupples said, adding that programmers pay careful attention to part orientation and a machine’s slat configuration for consistent cut-part support, sometimes changing a slat configuration to suit the day’s mix of parts.

In any situation, manual or automated, the shake-and-break slows throughput, and for most people it’s a thankless job. If rookies at Cupples’ spent their days shaking and breaking, they probably wouldn’t stay at the company for long.

They also wouldn’t stay long if they worked amid chaos, scurrying from shuttle table to shuttle table, sweating profusely to remove parts before the laser finishes cutting the next sheet. But they don’t scurry. After the laser finishes its cycle, the dual-shuttle system removes the cut sheet and replaces it with a fresh one. Rookies unload the pieces in an orderly fashion, and they chat with veterans while doing so to learn how and why the operation works so smoothly.

For instance, they learn that though the occasional part might need to go through the part leveler, they don’t need to go through flat-part deburring. “Our general rule is we want less than a 0.005-in. burr on the edge, which industry standards say is essentially no burr at all,” Cupples said. “So if we can’t achieve a burr less than 0.005 in. consistently with a fiber laser, we use our CO₂ lasers. Still, we do production cutting with 10 mm and thinner with nitrogen, and 99% of that is cut with the fiber laser.”

Another example: A veteran sorting parts might point out two narrow parts that will be left- and right-hand pieces that will be formed into narrow channels. They’re nested adjacent to each other but mirrored so that edge-geometry attributes are opposite each other. The rookie recalls that material yield is incredibly important, and yet arranging these parts in this fashion seems to leave a wider web section. He brings this up to the experienced veteran nearby, and the veteran explains about the release of residual stress after cutting, as well as the nature of forming tolerances on the press brake. The long, narrow blank is bowed ever so slightly, because the laser released stress that was trapped in the sheet.

The mini-factory team does all it can to avoid this, of course. They work closely with purchasing personnel and study how cutting affects stock from different mills and service centers. In fact, the company adjusts its cutting tech tables based on what it knows about certain material from certain sources. Two identical sheets of the same grade and ASTM designation might cut differently if they come from different places.

Programmers also nest and program the laser to minimize these effects, ensuring the laser takes a path to “push the heat” of the laser away from the part, perhaps orienting the piece in a way that mitigates the effects of residual stress and complications in subsequent forming.

But in rare cases, an ever-so-slight bow is just inevitable. In most cases, this part would be sent through the part leveler. But for these parts, the customer doesn’t require it. The tolerances of the formed channels are what really matters. And orienting those two parts in the nest so they mirror each other gives the press brake operator two parts slightly bowed in opposite directions. This allows the brake operator to push the tolerance error in the same direction, to the noncritical dimension, on both the left-hand and right-hand channels.

Cupples added that a veteran chatting with a rookie probably wouldn’t delve into all the detail immediately (otherwise, cut parts would never be unloaded and sorted in time). Regardless, the manual unload operation gives people an opportunity to really look at a nest of cut parts, talk about them, and learn. Rookies learn how the operation works as well as it does, and experienced people gain insight for further improvement.

The company performs both static and automated dynamic nesting, and which strategy it chooses depends on the customer and the parts being cut. “A nest isn’t all about density,” Cupples said. “We need consistent parts. And if we’ve got tight tolerances, we need to pay attention to the material grain direction. There are so many scenarios, and we’re set up to work with all of them every day.”

Nesting, Part Flow, and Staffing

Although it sounds counterintuitive, the fact that Cupples’ J&J has a good amount of repeating work, all organized in those mini-factories, makes its manual unload and part sorting more effective. If managers had to spread part-unload labor among 19 lasers that produced nests of small-lot parts from dozens or hundreds of customers, well, chaos would reign. Again, the company does short runs and dedicates a “miscellaneous” mini-factory to them, but production cutting is its bread and butter.

To keep manual part sorting operating like a well-oiled machine requires good production planning and visibility. Some of Cupples’ largest customers have online portals with demand forecasts. Forecasts change, of course, but at Cupples’ they’re critical to ensure good labor management and part flow.

Customer demand dictates the nest, and at Cupples’ demand is a bit more predictable than, say, a small job shop with hundreds of small-dollar customers. Over time a mini-factory’s programmers and estimators work together to create the optimal part nest, balancing the need for high material yield, good part consistency, and smooth part flow—including part sorting.

They match the right nest of parts with the right laser and available part-sorting labor. If the lasers run a batch of thick material, the mini-factory manager might schedule just two people to run three machines. The cutting cycle time is long enough so that two people can initiate programs and unload parts before the laser is finished cutting the next plate.

Similarly, if a part is full of small, hole-intensive parts, the cutting cycle time will be longer, so the operation might need fewer sorting personnel. One person might be enough to run the machine and sort parts. Conversely, if a powerful laser cuts a nest of just a handful of large parts, the laser finishes within minutes. This requires a team of sorters to be at the ready to offload large parts (with lift assists) before the laser is finished cutting. Alternatively, a programmer might choose to nest several large parts surrounded by smaller parts. This lengthens the cutting cycle and gives sorters a little more time to offload.

“We have flexible sorting crews that grow and shrink in number, depending on the length of the run on the sheet or plate,” Cupples said.

Cupples added that everyone in the mini-factory is cross-trained. This not only makes part-sorting capacity flexible, it also helps with employee engagement. Workdays are interesting, dynamic, and anything but repetitive. Someone might sort parts for an hour, run a brake, assist with nesting, initiate a laser program, then go back to sorting, ensuring those parts stay on the move downstream to the next operation.

How to Stay Unique

Cupples chuckled. “There are two 10-kW fiber lasers at other shops less than a mile away from me. We are surrounded!” He added that nearby steel service centers are installing high-powered fiber lasers too. “These are billion-dollar companies that are stepping up,” he said. “We need to gain an edge somehow.”

Cupples’ has gained that edge with a two-pronged approach. First, it’s a one-stop shop, offering not just cutting (including plasma and waterjet), bending, rolling, welding, painting, and assembly, but also extensive machining. It’s not a small machining department, either; it’s a full-fledged machining enterprise.

Second, it’s a bleeding-edge technology adopter, especially when it comes to lasers. The place has a clean room dedicated to cleaning and maintaining laser optics. This includes the optics of its eight CO₂ lasers—which still keep busy cutting thick stock—and the company does clean and maintain some of its older fiber laser heads.

Except for swapping the bottom cover slides, the newest fiber laser heads are sealed and can’t be accessed except by the laser OEM. But that doesn’t stop the fabricator from perfecting the process. For instance, on its 12-kW Eagle fiber laser (sold in the U.S. through Fairmont Machinery), Cupples’ team studied the cut. They knew the beam had the power and focus to make a good cut extremely quickly, but could it be even better? They looked at the nozzle and had a thought.

“We said, ‘Hey, we’ve got machining capability, and we have copper stock. The machine manufacturer is onboard with this, so let’s cut our own nozzle and see what happens,’” Cupples recalled. That nozzle, designed to promote laminar flow and reduce turbulence of the nitrogen assist gas throughout the kerf, sped the cutting speed by about 20%. “The last time I checked, we’ve been cutting 3/8-in. carbon steel at about 305 inches per minute.”

At FABTECH^® 2019, that nozzle—informally called the Cupples Nozzle—was on display at the Eagle Laser booth. As Cupples recalled, “The 15-kW machine at the show was cutting 3/8-in. steel at 390 inches a minute with a Cupples Nozzle.”

For years Cupples’ has collaborated with various machine-makers, including Bystronic and Eagle, to perfect machine design and brainstorm laser processing ideas. The shop operates 13 Bystronic lasers (three of which are 10-kW fiber lasers), four Eagle systems (including 12-kW and 15-kw models), and two Amada CO₂ machines.

That said, being a bleeding-edge adopter has its risks. “We’ve taken our lumps, let me tell you,” Cupples said. “We’ve destroyed millions of dollars of cutting heads. When we run machines, we run them to the limit. I’m an engineer. If we can’t break it, then it’ll work.”

Considering the incredible advances in cutting speed in recent years, the risk usually pays off. If a new machine experiences major hiccups, it rarely affects overall capacity. In fact, cutting capacity almost always increases, despite the unplanned downtimes.

Cupples recalled installing a 6-kW fiber laser, the first installation of its kind in North America. “We seemed to be alpha and beta testers on that one,” he said. “During the first six months, the machine didn’t run half the time. But still, we were on the leading edge of technology, and we were still getting the output. Yes, the machine was down half the time, but the machine ran twice as fast [as our older laser], and the accelerations were so much better. So, ultimately, we still had more output for less money.”

That said, Cupples is fully aware that not every company—including publicly traded service centers—would be willing to take such risks and be on the bleeding technological edge. Taking those leaps sets Cupples’ apart from the competition and, not least, increases the technical knowledge of many working there.

It also allows the company to collaborate with a variety of industry vendors, from Bystronic to Eagle to High-YAG, to help them develop the best products possible. Such collaboration—from end customer to fabricator to equipment-maker—is why The FABRICATOR’s publisher, the Fabricators & Manufacturers Association—launched a half-century ago. Cupples’ J&J, which has added more than 100 employees over the past 18 months, is proof of how well that collaboration really works.