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maintained a steady, repeatable rate of production. The towel-dis- penser line, where the cobot was to be tested, formerly saw parts injection molded in one building, packaged, and moved across the street to the assembly facility. Bartle admitted this was inefficient on var- ious levels, but also noted that it was less complicated than trying to put a large assembly line adjacent to a molding machine. Notably, it protected against an inherent risk with that kind of inline assembly scenario: "If you run short on assembly people one day, you might not be able to run the entire line," Bartle says. "Whereas, if I have the injection molding machine separate, I can at least run the parts. I'm not shutting things down because I'm a person short on assembly." One of the advantages claimed for cobots is that they don't need "hard" guarding to protect human workers in the vicinity. However, in this case, the cobot is largely isolated from likely human interaction. In the cobot-centered setup, WPI integrated the two injection machines that make the body and the cover of the dispenser. Situated next to each other, they mold parts that are conveyed to a central assembly station. The UR5 cobot removes parts from the machine and places them on a pad-printing fixture, where a customer logo is added. The robot then switches the housings to a second pad-print fixture, where a second customer logo is imprinted. The cobot then pivots and sets the parts on a conveyor for final assembly (see a video of the cell in action at short.ptonline.com/WPI). "By having the robot in between, it allowed us to really reduce the size of the assembly line," Bartle says, "because the cobot can do multiple tasks in less space than would be required with a human assembly line." WPI brought in a new pad printer for the cell and had some special integration fixtures built to help the robot. The machines are running When the employees at Wisconsin Plastics Inc. (WPI), first met their new coworker, a UR5 collaborative robot, or cobot, from Universal Robots, Ann Arbor, Mich. (universal-robots.com), they saw a threat to their jobs. Today, they see an opportunity to work more efficiently. "Initially everyone was concerned about the robots replacing them," explains Carl Bartle, plant manager. "Once they realized the robot was there to help their own efficiency, there was a lot of excitement." Based in Green Bay, WPI (wisconsinplastics.com) is a contract manufacturer with an emphasis on injection molding and assembly, including its own line of paper-towel dispensers. Game to see how a collaborative robot might fit into its business, the company targeted an existing product—one of its most compli- cated, in fact—as a test case for integration of a cobot. "We picked one of our more complicated assembly lines for the cobot," Bartle says, "one that actually had the most intense human interaction and the most variable rate to it. We figured that if we could do that, we could do anything, so we went all out on the first one." KEEPING PACE A key concept for WPI throughout the process was pace. Not neces- sarily getting employers to work faster, but creating a process that By Tony Deligio Senior Editor Custom fixtures allow the cobot to take on different tasks. Cobot Helps Molder Keep Pace Collaborative robot boosts process efficiency by 25%, while unburdening workers from the shop floor's more tedious tasks. 'The robot didn't speed anything up; it just works consistently at the same pace. There are fewer distractions for the robot.' 24 FEBRUARY 2018 Plastics Technology PTonline.com A U T O M AT I O N Close -Up On Technolog y