Star Metro - 20XP Collaborative Paint Cobot

Engineering an Easy-to-Use, Explosion-Proof Cobot for Painting

The 20XP incorporates a UR20 cobot that's modified to be explosion-proof and an innovative programming system to create a safe, easy-to-use method for automating painting processes.

Using robots to automate painting processes isn't a new concept, but only recently has the industry been able to take advantage of collaborative robot (cobot) technology. Not only are cobots smaller and easier to install than traditional industrial robots, they're also easier to program and re-deploy.

But cobots have faced a barrier to integration in painting and coating applications. These processes release volatile organic compounds (VOCs) into the air, which could cause explosions if they get into a robot or other piece of equipment and are ignited by a spark from the electrical systems. Any equipment that works in these environments needs to be explosion-proof, and most cobots are not.

Michael Kreps, president of AI Automation, wanted to bring the benefits of cobots to the painting and finishing industries by adapting cobots from Universal Robots to meet the needs of these industries. "They've really come up with a user-friendly interface for programming, use and installation," he says.

Universal Robots' cobots aren't explosion-proof, but when the company released its UR20 model, Kreps and his team took notice of its re-designed joints. "We looked at it and said, "This lends itself to creating the environment that would allow us to get approval for being explosion proof," he explains.

Reverse Engineering an Explosion-Proof Cobot

Joints on previous UR models had openings that were covered with plastic caps, enabling maintenance workers access to service the servomotors. Kreps says these thin plastic caps weren't compatible with the stable, pressurized environment needed for an explosion-proof cobot. The UR 20 eliminates this issue. "They actually made it out of cast aluminum, and it became a solid unit, which allowed that air flow to go through there," Kreps explains. "The inherent design of it has a sweeping curve on the inside so that there's no pockets or anything to hold any type of volatiles if any actually got in there."

Kreps and his team purchased a UR20 and took it apart to confirm the cobot was workable. Then it met with representatives from loss prevention specialist Factory Mutual and the nonprofit National Fire Protection Association to determine what specifications it would need to meet to create a certified explosion-proof cobot "And we started to reverse engineer from there," Kreps says.

Two engineers spent more than a year testing different ways to make the cobot explosion proof. "We must have rebuilt the robot several dozen times, trialing different ways of sealing it off," Kreps recalls. The team also faced the challenge of finding materials that could hold the needed pressure without degrading or possibly sparking. "We had a whole team working on it, including a bunch of polymer chemists and scientists that made sure that we made the right call on the materials," he says.

In the end, the team devised a patented method to modify a UR20 so it's pressurized to meet the specifications to be certified as explosion-proof. This includes requirements for how much air needs to be within the system, how many air exchanges need to occur and continuous monitoring of the air pressure. If the system detects a loss of air pressure, it sends a signal to a purging unit to purge the system, as well as a signal to the controller to shut off power.

Not only is the resulting system, called the 20XP, certified in America, it's also ATEX-compliant for European users. According to Kreps, before every modified cobot leaves its facility, it goes through a barrage of tests to validate that it's working correctly, including in cases of pressure failure. The organizations that issue these certifications track the serial number of every modified cobot to ensure it's only operating in the region in which it is certified.

Programming for Painting

In addition to the explosion-proof cobot, the 20XP comes with two stands: one to mount the robot inside the paint booth, and one for the controller and other elements outside the booth. Users can mount the robot stand to the ground or paint booth or leave it on the leveling pad the 20XP provides. Kreps says that, although most paint robots don't need to be moved once installed, the company has mounted the 20XP on a track so it could be moved out of the way to enable users to hand-coat parts if needed.

Cobots are known for their easy programming processes, but the 20XP uses motion-based Mimic technology from Danish company Nordbo Robotics to make programming the cobot for finishing processes even simpler. 20XP includes a 3D printed replica of a paint gun. The user pulls the trigger on the replica and goes through the motions of painting the part. "While you're going through those motions, the system is recording every single attribute that your hand does. When you're done painting that particular part and you stop, you walk out of the paint booth, go to the computer screen and hit save. You would call it whatever you wanted to name it, and you just programmed the robot," Kreps explains. In addition to being easier to program than using a teach pendant or hand guidance, the Mimic system enables users to program sophisticated motions, such as hand rotation, that are used when coating complex parts. "Once you have that program, you just hit play and let the robot spray the very next part. If you don't like it, you just go in and do it again," he adds. This programming system makes the transition from painter to robot programmer seamless. "If you've got an employee that you would say is your best painter, that painter becomes your programmer," Kreps says.

Users can edit programs using a click-and-drag system on the computer if necessary. And for simple parts, users can program the system using traditional programming techniques, such as hand guidance or a teach pendant.

The 20XP works with standard spray guns and fluid delivery systems (though the company has a partnership with Graco). Kreps says that for single-component materials, users input attributes such as fluid flows and air atomization pressure, and the system has software that runs in the background to control them. For multi-component materials, the robot and fluid delivery system can communicate with each other to properly apply the coating as the robot goes through its programmed path.

Applications

The UR20's 1750-mm reach enables a wide range of painting applications, from large parts such as automotive bumpers to larger batches of smaller parts, such as automotive mirrors. "In the painting industry, you really want to maximize the amount of pieces that you can put in a square foot as it runs through your system because it costs you a lot of money to run that system," Kreps notes.

While slower speed of movement is traditionally considered a disadvantage of cobots when compared to industrial robots, Kreps notes that speed isn't the most important factor when automating a painting process. "You don't necessarily need it to be a fast robot," Kreps says. "You need it to be an accurate robot." He adds that the UR20's speed is sufficient to handle painting large volumes of parts. "We've had people that have conveying systems that travel at different speeds, and the robots can keep up with them," he says. At the same time, the ease of programming makes it suited to lower volumes as well. "It can be very good for one-offs and two offs-as well, because of how easy it is to program with the Mimic system," he adds.

Beyond Painting

Painting isn't the only application for explosion-proof cobots - they can be used for powder coating and other potentially hazardous applications. The company is working with a boat manufacturer on an application that involves applying gel coat and fiberglass to the bottoms of boats. Kreps also says that bakeries would be a good application for explosion-proof cobots, as flour is a flammable substance that can become airborne and potentially ignite. Kreps says another 20XP user is a company in Texas that handles hazardous, flammable waste. Previously, workers in full hazmat suits would move 45-pound bags of waste onto a conveyor that moves the waste into a kiln to be burned. The Texas heat, kiln and suits create a difficult working environment, and the 20XP offers a safe way to automate these processes.

In the case of the hazardous materials application, the UR20's payload capacity and reach are necessary. But not all applications require these capabilities. For now, the 20XP conversion process is only compatible with UR20 models. But Universal Robots has announced plans to redesign all of its cobot models using the same structure as the UR20. "The conversion process that we have patented will work on all of those," Kreps says. This will enable 20XP to release a whole family of explosion-proof cobots in different sizes for an even wider range of applications.

Kreps says its partnership Universal Robots and other companies including Nordbo, Graco and more make the 20XP possible. "We can offer the customer a truly full, turnkey solution," he says.

Contact: Michael Kreps, [email protected], 260-437-1009
Web Site: AI20XP.com

SOURCE: A.I. Automation LLC

View the original press release on ACCESS Newswire

A.Harris--SMC