Heat it where you need it

Brad Henry, laser operator for Superior Joining Technologies Inc., uses a laser machine for microwelding. Many parts the company produces are so small that SJTI commonly uses a penny to demonstrate the scale.

Ask a TIG welder to name the most important piece of equipment he owns, and he might tell you it’s the torch. An ergonomically designed, comfortable torch can take the torture out of welding. Another might tell you it’s the power supply or the software that runs it, allowing him to modify the waveform, experiment with pulse welding, or any of a hundred other variations that solid-state welding machines provide. Another might say it’s the shade. A cautious welder using a shade that is too dark for the job could be welding far too hot for thin materials.

If you were to ask Thom Shelow, he’d tell you the most critical item is an analytical mind. A co-owner and vice president of Superior Joining Technologies Inc. (SJTI), Machesney Park, Ill., Shelow had several years of welding experience working for other employers when he left behind the relative security of a steady paycheck to blaze his own trail as a welder for hire. He was based in a manufacturing hub centered in Rockford, Ill., which was a blessing in that he was surrounded by countless potential customers. It was also a curse because he was up against a vast number of entrenched competitors. He had established a solid reputation as a reliable welder, but he knew that wouldn’t be enough to be a success. He needed an edge to separate his business from the competition.

Business-to-business communication was on the cusp of a significant shift at the time. Cell phones and fax machines were at a tipping point, on the verge of being affordable to small-business owners. It seems quaint in 2015, but the year was 1992. For a freelance worker like Shelow, the convenience of the cell phone would be a minor miracle, freeing up a lot of time that would otherwise be wasted. He wouldn’t miss any calls. He wouldn’t have to drive around to find a pay phone to call the office to get any new messages. More importantly, it would expand his geographic reach. Manufacturers were accustomed to doing business with the welder across the street or across town, and at that time Shelow was still 25 miles away, in Rochelle, Ill. He figured he’d be in Rockford to pick up or drop off parts nearly every day, so if he got a call from a customer while he was in town, he would be at the company’s doorstep within minutes. That level of service would be unique in 1992.

A fax machine would reinforce the capability of the cell phone. For written information, documentation, drawings and drawing questions, a fax machine would eliminate the two- to three-day wait for information to come by mail.

He had the welding background to do the work. Dazzling his customers by communicating with them more or less immediately would help him get the work.

Welder for Hire

Like many welders, Shelow didn’t start out with any particular welding specialty. He worked for a couple of manufacturers doing a variety of work, welding whatever needed to be welded to build whatever needed to be built. Welding isn’t the easiest vocation under the sun, and sometime after founding SJTI in 1993, he found himself doing quite a bit of tool and die work, an especially vexing niche. Much of the work dealt with the minute details of plastic injection molds, often with features measured in fractions of an inch.

“Occasionally the die needed modification due to a design change, or a feature built up as the result of a machining error,” he said.

Developing this skill was anything but easy. While gas tungsten arc welding (GTAW) can be considered one of life’s great pleasures—it’s a quiet process that often produces beautiful welds—small-scale tool and die work can be thoroughly challenging. It takes a light touch and a lot of patience. Some of the work, such as making assemblies, is done by fusion welding, but repairs always require a filler material, some as fine as 0.005 inch in diameter. It’s always taxing and frequently frustrating, but nevertheless Shelow excelled, honing his skills on the variety of work that came with short-term assignments, working a few hours here or a few days there.

“Many companies had welders on staff who did tooling repairs,” Shelow said. “They’d call me when someone was out sick or too busy with other duties,” he said, referring to his earliest days as a freelance welder. “I’d spend a few hours or a few days working in their shop.”

Shelow didn’t realize it at the time, but new welding challenges on an even smaller scale awaited. He had tried using magnifiers in his own shop to get a better view of the work area, and they had helped, but he wasn’t satisfied. When he learned about an emerging concept, microwelding—by definition, welding under a microscope—he realized that this was the next step for him. He wasn’t aware of any shops in the area that had microwelding capability, so this would really set him apart from the competition. He took the plunge, invested in the equipment, and developed the techniques. To this day the company takes many jobs other shops wouldn’t touch with a 10-foot pole, like welding a fitting to a 0.100-in.-dia. tube with 0.008-in. wall thickness.

However, working on small-scale projects is not the company’s specialty; it was a valuable learning experience that helped SJTI develop its niche, which is low-volume precision welding. While welders most often are concerned with matters such as weld integrity and visual appearance, working with plastic injection molds requires close attention to the metallurgy of the tool steels. The work provided a thorough education in how metals expand and contract as they heat and cool. Shelow used this as the foundation for SJTI’s precision work and, combined with the knowledge and experience of the company’s dozen or so welders, he relies to this day on the knowledge he gained as a freelance welder.

“We can’t intervene in the physics, but we try to anticipate the effect of the process on the material,” Shelow said. “If we know how much a material is going to shrink, we make it expand and then let it shrink to the correct size. The amount of expansion and contraction is different for every application, but we have a lot of experience, so we usually don’t have much trouble with new projects,” he said.

This is where SJTI’s staff thrives. It uses its collective metallurgy expertise to help OEMs in the early stages of product development, handling the R&D, prototyping, and low-volume production. Applications include medical, dental, aerospace, electrical, electronic, and machine tools. Certifications include the American Welding Society (AWS) D-17.1 standard, which is for aerospace, and the National Aerospace and Defense Contractors Accreditation Program (Nadcap).

The company still uses microwelding equipment, but at the other end of the scale it has a TRUMPF TruLaser 7040 equipped with a 5-kW CO2 laser resonator. It has 6-axis capability and a working envelope that measures 13 by 6.5 by 2.4 ft.

Although many of the projects are large in size, most are small in quantity. As Shelow described it, “We specialize in small quantities of very tedious work.” SJTI is not a high-volume manufacturer, and most likely it never will be one.

“When the product’s volume justifies an equipment investment that would take it to the next level, the customer usually takes over the project and takes it in-house,” he said. While the continuous churn doesn’t provide SJTI’s staff much in the way of predictability or security, it does add to their experience, which is the next best thing.

Laser Microwelding in the House

SJTI’s experience with laser micro-welding is another case of using a careful analysis to move the company forward. Although microwelding is just a small part of the business these days, Shelow wasn’t averse to investing in a laser for this purpose when it emerged as a contender to GTAW.

“I did some research, and I became convinced that a laser would result in a better-quality part,” Shelow said. For the finest work, GTAW imparted too much heat. Another persistent risk, one that accompanied every weld start, was that the arc wouldn’t strike exactly where the welder intended.

“GTAW is notorious for side arcs, which can damage some of the fine features in a die,” he said.

Also, like other manual welding

processes, micro-GTAW is subject to slight variations in consistency, quality, and throughput from one welder to

the next. Shelow figured that laser microwelding, although still a manual process, would decrease some of this variability.

He also had noticed that the mold repair work, in which every job is unique, had been tapering off a bit. He was looking to replace that work with more production work, and with a microwelding laser, he would be well-positioned to do so.

SJTI invested in a Performance model from Rofin, a 50-W Nd:YAG unit that generates laser pulses from 0.3 to 50 milliseconds and frequencies up to 50 Hz. The system is equipped with a Leica microscope that provides 10x magnification. The focal point for the microscope is the same as the focal point for the laser, so the operator knows precisely where the laser beam will hit the workpiece. An optical filter eliminates a narrow band of light centered around the laser’s wavelength, 1,064 nm. Unlike a common welder’s helmet, which blocks most of the light, the filter for Nd:YAG allows the operator to see the work area clearly.

The unit is available in 120-V and 230-V versions, which draw 16 amps and 13 amps, respectively, for a power consumption of 2.2 kW when in use and 200 W when in standby mode.

It worked so well that SJTI invested in a second microwelding laser unit, one with a larger work area and the capacity to hold parts up to 200 lbs.

Right Place, Right Time

It would be an oversimplification to say that Shelow was in the right place at the right time. Indeed, he supplied a unique service to a market that demanded it, and a unique level of service, but it takes much more than that to be an entrepreneur. It takes a lot of confidence to start a business, boundless determination to keep it going through tough times, and a certain amount of savvy to adapt to changing market conditions and customers’ needs. The last one is probably the most important, and it was one of the lessons he learned before he started his own business.

“At that time, it wasn’t common for weld shops to use quality control or quality assurance procedures,” Shelow said. Before he started his own business, Shelow occasionally would hear a customer grumbling about the lack of documentation, and he didn’t forget that. As soon as he could afford it, he contracted a retired quality control manager to write a quality control manual. As the demands for compliance with ISO and AS standards spread from OEMs through their supply chains, SJTI was already ahead of many of its competitors.

Louis Pasteur once said that chance favors the prepared mind, and Shelow’s career is testimony to something similar. His willingness to consider new technologies is testimony that opportunity favors an analytical mind.