Application Stories

Welding Standards Spur Serco Growth

By standardizing its equipment, training and procedures, Serco structured its welding operations for growth that has seen the company's production space triple and output multiply more than 20 times in the past ten years.

A welder uses one of several Lincoln CV-300 machines.

Welding the supports on the underside of a loading dock leveler at Serco, a welder uses one of several Lincoln CV-300 machines at the plant. Large 1,000 lb. coil of .045" 70S-6 electrode in background eliminates frequent wire changes on repetitive, production applications.

 

Serco, a United Dominion Company, designs and manufactures a line of loading dock systems that includes dock levelers, dock seals, truck restraints, safety gates, and inflatable shelters. The company, founded in Canada more than 30 years ago, opened the Dallas facility after four managers bought the firm from its parent company about ten years ago. After five years under their ownership, during which the company's output multiplied fivefold, Serco became part of United Dominion. Today, the company owns several affiliated firms that operate under the Serco umbrella and continues to grow dramatically.

Serco dock levelers are available in a wide range of capacities to handle loads comfortably and safely. The leveler deck features a safety tread deck plate of high tensile strength steel, supported by structural channel beam construction. Structural members are fully welded to the front and rear header assemblies.

Welding's Critical Role

Welding plays a role in fabricating many of the company's products, but it is particularly critical to the fabrication of truck dock levelers. As Serco's facility grew from 40,000 sq. ft. to approximately 115,000 sq. ft. and the plant's annual output approached $25 million, its needs for better control of welding operations and more consistent quality also increased. Lack of equipment standardization made it difficult to achieve production efficiencies and maintain quality standards as production expanded.

Lincoln DC-600 Lincoln power source and twin NA-5 automatic wire feeders.

Lincoln DC-600 Lincoln power source and twin NA-5 automatic wire feeders are incorporated into this dedicated semi-automatic machine that uses Lincoln Innershield® electrode to weld hinge tubes to lip plates. Two such machines are used to perform the tube-to-plate welds, freeing up a previously used single-arm robot to weld vehicle restraints and other complex product components.

 

Michael Vosdoganes, Vice President Operations and Engineering at Serco, says that when he came to the company four years ago, there were only 12 to 15 pieces of welding machinery in the plant, with no clear-cut standards established. "I tried to standardize things, add skills and upgrade the facilities and equipment." Vosdoganes credits Bill Carpenter, of local welding distributor Matheson Tri-Gas (formerly Industrial Gas & Oxygen), with providing much of the training needed to upgrade the skills of the company's welders. Through Matheson Tri-Gas, Serco standardized on Lincoln Electric equipment, adding 10 to 15 welding machines over the last few years, as well as some 30 welding guns. Also added were a Lincoln Electric central high vacuum/low volume fume extraction system to provide cleaner air and a Genesis single-arm robot cell to improve productivity on higher-volume components.

Growth Demands Standardization

As the company grew, the need for standardization and improved training became apparent. "We had some excellent welders," Vosdoganes explains, "but there was no formal training, and the processes and testing procedures were not clearly defined." He reports that, in the last four years, all welders have become highly trained and most are certified. Almost all of the training is done in-house, with the assistance of Lincoln and other manufacturers. Weld procedures and test procedures are better defined, and the company is ISO 9002-registered. Vosdoganes says, "The quality improvements have been astronomical. The processes are followed, we audit the processes, and we have good documentation."

Closeup shows tube-to-plate weld setup.

Closeup shows tube-to-plate weld setup. Twin FCAW torch heads weld both sides simultaneously, increasing productivity and minimizing distortion.

Welding Equipment Paces Production

Most of the welding at Serco is done by the GMAW (MIG) process, Vosdoganes reports, using primarily .045" Lincoln SuperArc® L-56™ (AWS ER70S-6) electrode with Lincoln CV-300 power sources. This flows more easily and provides a more consistent appearance in these applications than the 70S-3 and 70S-4 used previously, he says. Shielding gas is a 90-10 Argon/CO² mix, although he notes that the company is moving toward a 75-25 mix in many of its applications. Typically, most stock is 1/4" to 3/8" steel plate, plus some tubes and angles. Fillet welds in the 3/16" to 3/8" range make up most of the welds, although some butt welds are also used. According to Vosdoganes, most welding is done out-of-position.

Lincoln CV-300 power source and LN-7 wire feeder

One improvement was the replacement of 60-pound spools of wire electrode with 1,000-pound de-reelers in some high-volume applications. This reduced the downtime formerly required for frequent spools changes.

 

An area still being developed is a Genesis Versa System robotic cell that includes a Fanuc single-arm robot equipped with two positioners and a Lincoln Power Wave 450 power source. Originally used for welding lip hinge tubes to flat stock, the robot now is being re-configured to handle production of another product where its flexibility will provide greater benefits. On its original job, the quarter-million dollar robotic cell had already paid for itself. "The payback was between eight and twelve months," Vosdoganes states. "It was a tremendous investment and has paid off well for us." Meanwhile, the company recently purchased two semi-automated FCAW machines dedicated to the tube welding operation. These were deemed a better fit for the highly repetitive tube welding operation, freeing the robotic cell for other uses. Each machine is equipped with a Lincoln Electric Idealarc® DC-600 power source and twin NA-5 automatic wire feeders that provide excellent control of each phase of the weld.

Single-arm Genesis Versa-System robotic cell

Lincoln CV-300 power source and LN-7 wire feeder are used here for fitup and welding on a dock leveler. Note fume removal system, as well as piped in shielding gas lines in background.

 

The move into robotics also highlighted the need for tightened tolerances and improved weld procedures. Serco purchases most components from outside vendors, and welders had been adjusting for out-of-tolerance parts. Because the robot could not make these adjustments, the parts had to be more accurate. This caused both Serco and its vendors to tighten their inspection standards, which also helped Serco achieve ISO 9002 recognition.

Single-arm Genesis Versa-System robotic cell

Single-arm Genesis Versa-System robotic cell is being converted from hinge tube welding to production of vehicle restraints. Welding power for the Fanuc robot is provide by a Lincoln Electric Power Wave 450 power source.

 

To further improve efficiency, Matheson Tri-Gas installed a manifold system to provide welding gases at each work station. Previously, cylinder gases were used throughout the plant. The savings in demurrage charges and labor needed to change cylinders have been significant. Also, since the only cylinders now used in the plant are for a limited number of specialty gases, there are fewer workplace safety concerns. "In our old facility, which was roughly 35,000 square feet, we had over 200 cylinders in the building at any given time," Vosdoganes recalls. "Today, I don't think we have 10 cylinders in the whole building."

Central high vacuum/low volume fume extraction system

Central high vacuum/low volume fume extraction system helps keep workplace free of fume. Suction heads at each work station remove fume, which is routed to this filter system through a manifold.


Teamwork Eases Growth Process

Much of the credit for the improvements made at Serco is due to the close teamwork between the company, the equipment manufacturer and the distributor, according to Patrick Fagerquist, Lincoln Electric's Dallas-based sales manager. "We all share what we're doing with each other," he notes, " and all three companies approach problem-solving with an open book." Bill Carpenter concurs, pointing out "Mike gives me the opportunity to go out in the plant and do what's needed." Vosdoganes adds, "He has complete free reign of the building anytime. We could put in an office out there for Bill because he's just like part of Serco. A lot of what we do in improvements is a consequence of what Bill and Patrick and Lincoln have done for us, and that's why they have free reign here"

When Vosdoganes first joined the company, he revised the plant layout to improve material flow. Using the same approach, he laid out the new plant so production would move through without back-tracking. He says, "you can go forward, you can go sideways, but never backwards." The same rule seems to apply to the company overall.

Collectively, the equipment upgrades, training and standardization continue to pay off in increased production. "Currently we're building anywhere from 225 to 350 levelers a week," Vosdoganes reports, "so Serco is doing very well."

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