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Automation in Abundance, Arc Welding Included

November 1, 2022
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Robotic arc welding productivity jumps 30 percent when a new state-of-the-art cell steps in for one nearing the end of its useful life. Upgrades in robot performance and welding technology improve weld quality, reduce rework and make spatter removal a distant memory.

One broad brush stroke across the landscape of third-generation family-owned and operated Haake Manufacturing Co. and you can’t help but notice how important automation has become for the sheet metal stamper and fabricator.  Dotting its 100,000 sq. ft. of manufacturing space, spread over five buildings in DeSoto, MO, are several laser cutting and CNC punching machines serviced by automated sheet-handling systems; a robot-tended press brake; and the subject of this article—a twin-workstation robotic arc welding cell.  

A OTC Daihen robotBorn in 1948 primarily as a tool and die company and metal stamper, Haake’s evolution into fabrication started around 1990 when current company president (and third-generation owner) Reggie Stockwell and then company president, Fred Haake, opened the doors to growth, says company vice president Jay Rieker (Stockwell’s nephew). They did so by purchasing the firm’s first laser cutting machine, a Trumpf model. Today the firm operates eight Trumpf machines (laser cutting, CNC punching, a punch-laser combo and press brakes), while also continuing to invest in stamping equipment by adding two new Aida servo presses in the last couple of years.

B OTC welding robotBut when it comes to automation, “the company likes to keep things exciting and state of the art,” Rieker says.  “When we decide to invest in new machines, we look for opportunities to automate them. We’d prefer to not have manual operators tend to these highly productive machines. I’ll hear Reggie Stockwell say, ‘What’s the point of having this amazing equipment if you don’t use it amazingly!’ So, we look to automate everywhere we can, typically finding that the automation pays for itself repeatedly, while also improving worker safety.”

Upgrading Robotic-Welding Operations

A process ripe for automation, as many metal formers know, is arc welding, and it comes as no surprise that Haake was an early adopter. Like its other automaton equipment, Haake’s investment in robotic welding, going back some 15 yr., has helped enable the firm to grow, expand operations and take in new customers without adding a lot of manual labor. The headcount has remained near 65 even as it has continued to expand, more recently by adding 30,000 sq. ft. of manufacturing space to bring powder coating inhouse.

Haake’s material mix is broad and evenly shared among aluminum alloys, stainless steels and carbon steels, including galvanized; the material-thickness sweet spot falls in the 22- to 7-gauge range, Rieker says.

“We perform a lot of work for companies where aluminum often gets the call,” he explains. “Overall, we shipped 4.5 million parts last year for some 120 different active customers. We also supply the bar industry, aftermarket automotive, HVAC and even prisons, among others.”

Among its most recent capital-equipment investments, to maintain pace with its growing customer base: a new robotic-welding cell, added in 2019 to take over for its aging workhorse. “We still use that old robotic welding workcell occasionally,” Reiker says, “but only out of necessity as demand requires it.”

The new welding cell on the block: an OTC Daihen Eco-Arc 200, with OTC Daihen’s exclusive Synchro-feed welding package designed to provide ultra-low spatter, and ideal for the wide mix of material thicknesses at Haake, especially thin-gauge parts with outside corner welds. Anchoring the cell is a model FD-B6 six-axis arc welding robot—6-kg payload capacity, 1445-mm reach and built-in wrist motors to avoid interference with jigs and workpieces. It also boasts built-in cables to avoid weld-conduit interference and improve torch reach. And, OTC Daihen touts a seamless, high-speed digital connection to the welding power supply and a built-in mechanical shock sensor as part of the package.

Aluminum Welding Shines

“Researching our robotic-welding options in 2019, we really appreciated the ability of the OTC Daihen cell to shine when welding aluminum,” Rieker says, also noting that the cell’s flexible tilt-turntable positioner allows it to complete complex weldments without requiring the robot to perform acrobatic maneuvers.

“We have one job, for example, welding an aluminum tube to a bracket for an assembly used in the sign industry, which requires a convoluted circular weld path,” he explains. “We can use the tilt-turntable to maneuver and spin the part under the stationary welding torch to maintain the proper torch orientation to the weld joint.”

The OTC Eco-Arc production robotic arc welding systems are two-station, two-table configurations that allow an operator to unload a finished weldment and reload parts into a fixture on one worktable, all while the robot welds on the second table. OTC offers the systems in several configurations—as a cobot production cell, a compact cell, a cell with fencing that anchors to the floor, a cell with the fencing mounted to a common base and large cells featuring long-reach robots and larger weld tables.

Haake’s system employs the OTC Daihen Synchro-feed gas-metal-arc-welding setup—500-A inverter-based pulsed power supply (OTC Daihen model WB-P500L) and weld-wire delivery system—that, OTC Daihen officials say, virtually eliminate weld spatter. Via a welding process called PulseDip, the setup incorporates a servo-driven wire feeder within the torch body that advances the welding wire forward to create the arc, and then precisely retracts the wire while synchronizing with a weld-current waveform that extinguishes the arc. The result: consistent droplet transfer into the weld joint with minimal if any spatter. 

C Robotic arc weld OTC DaihenThe WB-500L power supply employs OTC Daihen’s Wave Pulse process that delivers high-speed waveform control, for spatter control as well as to minimize undercut during high-speed welding. OTC Daihen also touts the power supply for eliminating the need for expensive helium-based shielding-gas mixtures, enabling instead the use of 100-percent argon on aluminum, and argon-CO2 mixtures when welding stainless steel.

Simpler to Program and Run

“Compared to our older robotic welding cell, we’ve found the Eco-Arc much simpler to program and operate,” Rieker says, noting that his programmer can develop new robotic welding routines in 1 to 2 hr. using a teach pendant at the cell.  

“And, while previously the operator tending our older cell required a lot of expertise in welding to avoid quality issues,” he adds, “when that operator left the company, we were able to replace him with a cell operator who knew how to program robots but lacked that higher level of welding expertise. That’s because the OTC Daihen welding system is so intuitive and forgiving; the operator does not need to have a lot of welding skill or knowledge. This new cell really does make it much easier for fabricators to adopt robotic welding.”

Faster and more intuitive to program helps make for an easily adaptable and productive piece of automation, but when weld quality and repeatability also improve, then you’re on to something, and that’s precisely the case at Haake. “We experience little to no spatter,” Rieker confirms, “and part-to-part results are very consistent. We never have to worry about wasting time manually touching up welds or wire-brushing to remove spatter. 

“Overall, we’ve experienced a 20-percent improvement in throughput compared to the older cell,” he adds, “and gained probably at least another 10 percent in overall productivity when you include the improvement in weld quality.”

As An Example

…Rieker describes an assembly it runs regularly through the robotic arc welding cell: thin-gauge stainless-steel weldments for a wastewater-treatment application. Here, the robotic arc welder joins a 10-gauge base plate to a 22-gauge wrapper.

“Throughput on that job has increased by nearly 20 percent,” Rieker says.

One final key to success when it comes to robotic welding in a relatively low-volume, high-mix environment such as Haake’s: quick changeovers, and here Rieker identifies a couple of enablers.

“First, the robot carries a multifunction welding torch that makes the changeover from welding stainless or carbon steel to aluminum quick and simple,” he says. “We don’t have to change out the entire torch, only the gun liner, which takes less than 30 min. Second, we design and build our weld fixtures to use common base plates where possible, with tooling inserts so that each fixture can handle multiple part families. We try to not over-engineer the fixtures, so they’re easily modified. Of the 50 or so fixtures we’ve built only 15 or 20 are regularly used.” MF

Industry-Related Terms: Alloys, Carbon Steel, Case, CNC, Corner, Die, Fixture, LASER, Model, Plate, Point, Powder Coating, Spatter, Stroke, Transfer, Undercut
View Glossary of Metalforming Terms

 

See also: OTC-Daihen, Inc., TRUMPF Inc., Aida-America Corp.

Technologies: Welding and Joining

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