The cobots—that's right, cobots—are coming

Collaborative robots, or cobots, as insiders call them, created something of a buzz at PLASTEC East in New York City and Plast-Ex in Toronto this month.

On the Plast-Ex show floor, ABB (Zürich) showed off its YuMi robot, which it premiered earlier this year at the massive Hannover fair in Germany. The company is calling it the "world's first truly collaborative dual-arm robot" that can work safely alongside humans. Meanwhile, in both New York and Toronto, Universal Robots (UR; Odense, Denmark) highlighted its single-arm model, while Rethink Robotics (Boston), which might want to challenge ABB's claim, showcased its dual-arm Baxter robot going through the motions. Presentations on the Center Stage provided insights into the technology and explained how it would alter the workplace in the years ahead at companies large and small.

One question that cropped up during the presentations, not surprisingly, was, what exactly is collaborative robotics and how is it different from conventional robotics? John R. Henry, owner of the Changeover.com consultancy, recently outlined a set of characteristics in sister brand Packaging Digest. Here is what he wrote in "What are collaborative robots and why should you care?".

"Collaborative robots and applications generally combine some or all of the following characteristics:

  • They are designed to be safe around people, either by force limiting to avoid injury if they touch, by sensors that prevent touching, or by a combination of both.
  • They are often relatively lightweight and can be moved from task to task, as needed.
  • They do not require skill to program. Most cobots are simple enough that anyone who can use a smartphone or tablet can teach or program them.
  • Just as a power saw is intended to help, not replace, the carpenter, the cobot is generally intended to assist, not replace, the production worker.
  • Collaborative robots are generally simpler than more traditional robots, which makes them cheaper to buy, operate and maintain."

That last point is key, as cobots typically cost between $25,000 and $40,000 instead of the $1 million or more that conventional industrial robots fetch, and this is putting automation within the reach of small operations. It's no wonder that collaborative robotics is expected to experience explosive growth in the next few years, with the market surpassing the billion dollar threshold by 2020, according to ABI Research. Cobots are also nimble, able to perform a range of tasks, unlike industrial robots, which are designed to do the same thing over and over again. These were among the reasons that Oticon (Smørum, Denmark), one of the three largest hearing aid manufacturers in the world, enlisted a UR robot to remove tiny plastic parts from a molding machine.

 

Oticon Universal Robot
The UR5 robot gently removes parts smaller than 1 mm
from a molding machine at Oticon.

Automation is not a new concept at Oticon—the company has been using robotics technology for a decade, says UR. But ongoing size reduction of hearing aid components to make the devices more comfortable precluded the use of existing two- and three-axis robots. And humans could not reliably perform these operations, which involve parts as small as 1 mm. "We were looking for a solution that could suction the small parts out of a mold," said Arne Oddershede, group leader of the maintenance unit at Oticon's test and production center in Thisted, Denmark. "This was impossible manually. We needed a flexible technology that would also be economically viable for smaller production runs."

The need was met by systems integrator Armiga, also based in Thisted, which used a UR5 six-axis, articulated robot arm weighing 40 lb with a payload of 11 lb.

"We realized that two- or three-axis robots were not suitable for the job. Lateral and vertical movements were nowhere near sufficient. If, for instance, a small part is stuck in a mold, it must be possible to tip it out," said Lars Gasberg, Sales Manager at Armiga.

Other features that appealed to Oticon included the robot's intuitive user guidance and its precision and flexibility. Rapid advances in medical engineering have resulted in constantly changing production processes and a broader range of hearing aid models that require a flexible robot handling smaller batch sizes, said Oticon.

The robot was installed in one day at Oticon's molding shop. Mounted on the injection molding machine, the robot can position itself over the mold and suction the plastic parts using a specially designed vacuum system. The suction tool can accommodate up to four tiny components simultaneously. The UR5 is programmed to engage the suction mechanism only when the mold is open. Once the parts have been removed, the robot retracts, allowing the injection molding machine to begin a new operation. All the components from the same mold are subsequently collected in separate tubes for traceability purposes. The vacuum system also ensures that the sensitive elements are not damaged.

More complex molded components are handled with pneumatic gripping tools. Because of its six axes, the UR5 is very manoeuverable and can rotate or tilt the parts in order to lift them quickly out of the mold.

The robot works in four- to seven-second cycles, depending on the size of the production run and the component.

The easy teachability of these robots, which can be as simple as grabbing the robotic arm and showing it the motion sequence using waypoints, also appealed to Oticon. "Since we produce different batch sizes and components when developing new products, it must be possible to easily reprogram the robot," said Oddershede.

Because it is collaborative, the UR robot can work directly next to employees without any safety fencing. Built-in force-sensing technology stops the robot if it comes into contact with an employee.

The $24,500 investment paid for itself within a few months, according to Oticon, and an energy-efficient design ensures that operating costs remain reasonable.

Oticon has now deployed a second robot for the same field of application at its production site in Poland.

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