Cobots Keep Stamping Presses Fed at WI Manufacturer

November 25, 2020

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There’s a shining, shooting star in the world of industrial automation. Collaborative robots, commonly called cobots and designed to work safely, economically and productively alongside humans in a variety of applications, are exhibiting impressive market growth as manufacturers employ them in new ways on a daily basis.

Economical to obtain and simple to program and deploy, cobots, as detailed in a recent report from ReportLinker, Global Collaborative Robots (Cobots) Market, 2020-2030, offer significant productivity potential and a rapid return on investment. Given the profit potential, it’s no wonder that the Robotic Industries Association (RIA) anticipates cobot-sale revenues to reach 34 percent of the overall industrial-robot market by 2025.

As RIA officials note, in many cases little to no programming is required to install cobots, thus reducing integration costs, and their increasing flexibility opens up a range of manufacturing tasks and applications.

Count Erik Larson as a cobot believer. As vice president of operations for Processed Metals Innovators (PMI), Larson oversees all manner of sheet metal forming and fabrication at the company’s 130,000-sq.-ft. manufacturing plant in Bloomer, WI, home to 140 employees. The PMI shop floor boasts 15 mechanical stamping presses in capacities from 22.5 to 1000 tons as well as a 2000-ton hydraulic press. The fabrication side of the business counts a CNC punching machine, six press brakes, three laser cutting machines, and robotic and manual welding stations. PMI also provides service-center functions via inhouse cut-to-length and slitting lines.

In 2018, Larson and the PMI management team took note of cobots at an industry event, and set about determining where the technology might fit. Doing so entailed a discussion with Hirebotics, an automation integrator that provides cloud-connected robots on a rental basis, eliminating capital outlays and simplifying applications while freeing associates for value-added and/or less hazardous tasks.

Simplified Solution to Press Tending

“We have some large welding robots, but we’ve never tried to set them up for tending presses and moving parts,” Larson explains. “Given that, along with a serious labor shortage, we decided to give cobots a try.”

A Hirebotics team visited PMI and targeted a three-press operation used to form relatively flat parts, without frequent die changes or other factors that might necessitate excessive programming, as an ideal initial cobot application. The firm installed two Universal Robots (UR) UR10 cobots in January 2019 to serve two mechanical presses―250- and 300-ton capacities―operating side-by-side in the work area.

PMI’s own install requirements were minimal, consisting mainly of running a compressed-air line, installing baseplates to precisely locate the cobots, and purchasing part-feed conveyors. No problem with electrical, as the cobots run off of 110-V current, and though the cobots are safe enough to operate in proximity with humans, PMI has installed floor-based sensors to protect personnel not from the cobots, but from parts as they transfer to and from the presses. The parts themselves, 0.054-in.-thick aluminum stock and measuring 22 by 40 in., are destined for residential stand-by electrical generators.

Within three days of installation onset, the cobots were tending the presses full-time.

Through a business model designed to ease cobot integration in manufacturing environments, PMI rents the UR cobots on an hourly basis, allowing PMI to focus on core competencies in stamping and fabricating as opposed to material and part handling, and redirect valuable associates to other tasks.

Cobots-baseplate-press-tending “Initially, we shipped parts to Hirebotics, which developed pick-and-place cobot tooling (included in the hourly cobot rental), and then the two cobots and tooling were shipped back to us,” Larson explains, noting that, through information gained from earlier meetings, PMI was able to fabricate and install the cobot base plates in the correct locations ahead of time. “We already had the base plates anchored in when the cobots arrived, which shortened the ramp-up time.”

Presses, Cobots, Conveyors Intertwined

As mentioned, the cobots tend two presses in this operation, with the initial forming press tended by hand.

“An operator tends the first coil-fed press, which stamps the initial blanks,” Larson says. “The operator stacks those blanks on a pallet for transfer to the next press, where the operator then forms the part and places the formed part onto a conveyor for pickup by the first cobot. We would use a cobot for this work, but it’s too difficult to separate the oil-coated aluminum blanks. With steel, we could use magnets for separation.”

After initial part blanking and transfer of those parts to the conveyor, the two fixed-location cobots pick the parts off and place them in the dies of their respective presses, then unload the formed parts onto conveyors for continued travel down the line. On the conveyors, parts funnel down to sensors that stop the conveyors when parts reach their required location. Conveyor sideguides ensure proper part orientation for cobot pickup. Complete cycle time from pick to placement in the die to unloading of a part back on the conveyor is 24 sec.

“That’s slower than a human, but then again, the cobots are always on station (across PMI’s two-shift Monday-through-Thursday operations and single-shift Friday-through-Sunday work),” Larson says.

Hirebotics integrated the conveyors into cobot programming, with PMI integrating the cobot controls into the press controls, according to Larson. Essentially, a cobot runs each press, with sensors on the conveyors communicating part presence to the cobots, which then know to pick up the part. A conveyor will not move until a part is picked up, and a cobot will idle until the conveyor presents a part for pickup.

With a new part placed in the die, the press will know to cycle.

To ease troubleshooting and correction, Hirebotics provides a mobile-device app where designated PMI personnel can text an issue. For example, suppose a cobot must present a part 1 mm to the left within a die.

“Hirebotics will correct that in a matter of minutes,” Larson says. “Reprogramming occurs remotely, and we don’t need to do anything on our end. The cobot moves that next part to the left 1 mm and it drops correctly into the die.”

As mentioned, two part types run through this line, but despite similar dimensions they each require unique tooling. The permanent pre-positioned cobot baseplates ease the die-change process, as the cobots quickly can be removed for press-bed access and pinned and bolted back to their correct positions after tooling install.

Seeking Out More Cobot Applications

After witnessing cobot effectiveness in this press-tending application, Larson and the PMI team learned of BotX, a robotic arc-welding system developed by Hirebotics, Red-D-Arc and Airgas, and utilizing a UR UR10e cobot. PMI now incorporates a BotX in its fabrication department, and company officials envision more cobots soon dotting the shop floor.

Says Larson: “We have some ideas on where we might place more.” MF