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Simplifying programming of a paint and powder robot

Is this the robotic technology that metal fabricators with painting and powder operations have been waiting for?

a paint and powder robot

A painter manually guides the Lesta robot through the paint application process at DeGeest Steel Works, Tea, S.D. In doing so, the painter is programming the robot to repeat the very movements the painter used to complete the job. Once recorded, the program is stored and can be accessed again when the job is repeated. DeGeest Steel Works

DeGeest Steel Works Co. has been in business for 42 years, and it has painted for 42 years. It knows what its customers expect in terms of finishes, and it’s confident in its ability to deliver a quality product.

About two years ago, the company was looking to automate its finishing process. This was going to be part of a major facility expansion that would bring its total manufacturing space to 135,000 square feet.

Like with painting, DeGeest Steel Works was no stranger to the world of automation and robotics. It has seven robotic welding cells, one of which was built from the ground up by the company’s technicians. It also has a robust IT staff that has developed software to create a manufacturing environment where real-time manufacturing information is fed back and forth from the control center to the shop floor, allowing people to make the best decisions possible. For example, mobile scanners and tablets on forklifts and touchscreen tablets at every work station provide live production schedule updates, job notes, takt times, and latest revisions on drawings.

“We love our team that we have here, and we have a lot of fun together,” said Derek DeGeest, president of DeGeest Steel Works and the third generation of the family to be involved in the company. “As we were growing and introducing more automation to the fabrication side, we were overwhelming our paint department.”

With a desire to add robots to the paint operations, DeGeest said the company went to the parties it was most familiar with—the robotic companies involved with automated welding. Certainly companies that had helped to robotize U.S. manufacturing over the last 25 years could help a job shop looking to find new efficiencies in its paint operations, right? Not so much.

DeGeest said that a representative from one of the world’s largest robotic companies painted a picture that just wasn’t going to work for the job shop. The company said it needed to take DeGeest’s best painter and train him how to use its software to program the robots offline. If that painter learned the systems successfully, he would then be able to create a painting program over a couple of days and then shut down the paint line to spend another week or two to dial in the paint program. Another less appealing alternative was to pay the integrator to create a program for each part.

“I said, ‘We’ve got hundreds of different parts, so we can’t take two weeks to get a part ready or pay for each part,’” DeGeest recalled. “That wasn’t going to work for us.”

A bit dejected after the early search, DeGeest and his team turned to the Internet. That’s where they discovered an Italian robotics company called Lesta, which looked to be able to provide self-learning robots that mirrored human movements without the need for offline programming or a teaching pendant. The robot records the painter’s movement and spray technique while painting a part in a weightless learning mode, then the robot uses those movements for later replication.

“We know robots,” DeGeest said. “We thought this was too good to be true.”

Seeing Paint Robots at Work

The DeGeest Steel Works team traveled to Europe to see Lesta robots in action. They visited 12 different liquid and powder installations, ranging from a custom paint shop that did nothing but small lots of parts to large manufacturers producing and painting large components for things like industrial cranes. In the end, seeing was believing.

Two Lesta paint and powder robots

These two Lesta robots are used to automatically blow off and suck out water from parts leaving the pretreatment system. Lesta

DeGeest found out that these robots were different from other robots. Lesta designed them from the ground up for self-learning in hazardous locations for any size of manufacturer. They aren’t precision robots, like the ones used for welding, but they are suitable for use in applications for the coatings industry.

To program these robots, a painter initiates a programming sequence while every single motor in the robot is disengaged. The painter then manipulates the robot with the help of pneumatics. In this “free-float” learning mode, as DeGeest described it, encoders in all of the robot’s joints record all of the motions that the painter leads it through as the “training” paint job takes place. As the movements and gun trigger pulls are recorded, the robotic software creates the code.

At this point, the painter can initiate the program and see the end results minutes after programming the robot. The program is ready for action, now or in the future.

“I called back home, and my dad asked me how the trip was going. I told him, ‘Pretty good. We just bought two painting robots,’” DeGeest said.

That would eventually turn into six robots to boost its painting capabilities and launch a new business partnership with Lesta to bring these robots to North America.

Focus on the Paint Line

The paint line, of course, was the primary concern. DeGeest Steel Works has a pretty large part window, roughly 9 feet long by 10 feet tall by five feet wide. To accommodate this size and stay on top of production requirements, company officials elected to go with a four-booth system each with a Lesta robot. Booths No. 1 and 2 accommodate primer application, with two robots finishing the two different sides of a part; in Booths No. 3 and 4, two more robots perform the same function, but for the top coat.

The first painting program created in conjunction with the new line, which went live in July, was for a hydraulic tank. The painter used the robot while in learning mode to paint these tanks. This recorded the painter’s skills. When the painter went live with the program, he saw the robots do exactly what he had it do just minutes before.

“Our painter told me, ‘It’s hard to believe that’s me in there. I did that,’” DeGeest said.

So that’s four robots—what about the other two? DeGeest Steel Works is using its other robots right after parts exit the pretreatment system, which cleans the parts for paint application.

All manufacturers involved in powder coating and painting struggle with getting rid of as much moisture as possible—it’s often hidden in pockets and other hard-to-reach points—before the parts enter the dry-off oven prior to the paint booths. The presence of moisture on a part, even after exiting the dry-off oven, is a huge contributor to paint defects. To remove pockets of water, manufacturers might have someone stand near the dry-off oven to blow off every part destined for the oven, re-engineer parts so that they contain more drain holes, or simply turning up the oven temperature to bake off any moisture that might be hidden in the deep recesses of a part.

A painter manually guides the Lesta robot

A painter manually guides the Lesta robot through the paint application process at DeGeest Steel Works, Tea, S.D. DeGeest Steel Works

DeGeest Steel Works is using its two other Lesta robots to blow off or suck out trapped water on parts before they enter the dry-off oven. Just as they program the robots for painting, finishing line attendants are doing the same for these two robots. During programming, the robots are guided through the appropriate sequence to ensure the moisture is dealt with. The program can be made without a gap in production and called up when that part is ready for the paint line.

This is where the new business comes in. DeGeest Steel Works is now acting as the U.S. arm for Lesta. In fact, LestaUSA made its debut at FABTECH in Chicago, Nov. 11-14. Fabricators will be able to learn about the paint and powder robots and how DeGeest is using the technology to address the trapped water problems that most finishing line operators have to wrestle with.

Spreading the News About Painting Robots

The new business is coming along. After a long process to have the Lesta robots approved for use in U.S. factories, DeGeest said that the robots have achieved certification to prove that they are compliant with North American safety standards. DeGeest Steel Wroks has opened a test lab and showroom where fabricating shops and manufacturers can come in and test particular mix systems, spray gun technology, and paint formulations with the Lesta robots. DeGeest said that guest visits are increasing, as technology suppliers, paint companies, and large OEMs want to see what this new finishing automation is all about.

“We don’t want to be an integrator that’s going to replace other integrators. We don’t want to sell paint booths and cool down tunnels,” DeGeest said. “We want to work together to provide proven turnkey robotic solutions.”

The next step in the business occurs toward the end of this year, when LestaUSA starts manufacturing robots in Tea, S.D. This won’t be an assembly operation; the robots will be built from the ground up on the DeGeest Steel Works campus.

Meanwhile, the company is enjoying the efficiency of its new paint line. Three people—one person loading and unloading the line, another overseeing the automated blast machine that preps parts for paint, and another in the working in the prep area—run the entire line. The painters that used to spray the coatings on parts all day, sometimes even crawling under the parts to ensure full coverage, are now spending time programming parts, focusing on quality improvement, and basically using their expertise where it’s most needed. They also can enjoy vacations because the robots have been programmed with their knowledge on how best to approach paint application.

About the Author
The Fabricator

Dan Davis

Editor-in-Chief

2135 Point Blvd.

Elgin, IL 60123

815-227-8281

Dan Davis is editor-in-chief of The Fabricator, the industry's most widely circulated metal fabricating magazine, and its sister publications, The Tube & Pipe Journal and The Welder. He has been with the publications since April 2002.