A Paint Path Programming Payoff

Robot simulation and offline programming software is producing savings for North American Bus Industries.

At North American Bus Industries (NABI), in Anniston, Ala., workers used to manually spray-paint one 35- to 60-foot-long bus per shift, with the paint operation running two shifts per day. But in 2006, after NABI acquired several other bus manufacturers and made plans to consolidate production in Anniston, the company was suddenly looking at a big jump in volume. “That’s why we expanded here,” says Jeff Roby, paint manager at the NABI plant. “We needed to go from an average of 200 to 300 buses a year at each of the plants to several hundred buses annually in Anniston.”

Three-year payback

The company late last year completed a 50,000 square foot addition to its Anniston manufacturing plant, including a robotic paint line at a cost of several million dollars. NABI considered installing a new manual paint system, says Roby. But to meet anticipated volume requirements, a manual system would have required two lines, each running two shifts per day, with a total of 112 workers. The robotic line, by contrast, can meet expected volume needs running a single shift per day, with a need for 32 employees. NABI expects to achieve a payback on the robotic paint line investment within three years, says Roby, based largely on the labor savings.

The contract for the paint line went to ABB Robotics, Auburn Hills, Mich., which installed a total of eight of its IRB 5400 robots, two in each of four zones. Robots initially apply primer to the buses, which then move through a manual sanding booth and masking area before traveling through two robotic base coat zones and a final robotic clear coat area.

Several factors contributed to NABI’s selection of ABB Robotics, says Roby, including the availability of an ABB simulation and offline robot programming software package called RobotStudio. As part of the NABI deal, ABB used the RobotStudio software to simulate the line and develop robot paint programs for four different bus models. “We had 2D models of the buses which we sent to ABB, and their engineers transferred that to 3D,” notes Roby.

After creating the 3D bus models and placing them within a 3D model of spray booths on the NABI line, ABB engineers simulated the painting processes and developed paint path programs for download directly to the robots on the actual line. The approach eliminated the need for NABI personnel to train the robots using a point-to-point approach with a teach pendant, saving significant time, Roby says. The company has so far run three of the four ABB programs developed on RobotStudio, and start-up time for painting was about 10 to 12 hours for each, he says, instead of about 40 hours that would have been needed for each bus using a point-to-point approach.

As robot paint programs are needed for additional bus models, NABI will consider acquiring RobotStudio for its own use, says Roby. But depending on the economics, the company may commission ABB to do the additional simulation and programming.

Vendor benefits

The inclusion of RobotStudio simulation and programming is not uncommon as part of ABB Robotics contracts, says Alan Ketelhut, project manager for the vendor. Customers “often end up contracting us to do some of their virtual build on the computer so they can save time and money,” he says.

The capability provided by RobotStudio has also proven valuable to ABB Robotics’ sales effort, says Ketelhut. The software is increasingly being used by the company’s proposal group to verify a process prior to a sale. “At least in the paint world, we’ve really started using it pretty exclusively for process verification, so we don’t get stuck in a situation where we’ve proposed the wrong robot, or the wrong quantity of robots,” Ketelhut explains. 
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