BCR: A Robotic Vision
U.S. brick manufacturers have been hearing about the benefits of robots since the early 1990s. Everyone knows they can reduce labor requirements, improve product quality and increase production efficiencies. Everyone also knows that unless you’re building a new plant and have a lot of time and money available to purchase the equipment and train your employees, robotic systems simply aren’t feasible.
Or are they?
In 2002, Commercial Brick Corp., Wewoka, Okla., decided to challenge conventional thinking by commissioning an automated robotic packaging system from J.C. Smale & Co., based in Notting Hill, Victoria, Australia. Unlike other robotic systems in the brick industry, which are typically implemented in the setting stage, the robots in Commercial Brick’s plant would go only at the end of the line, in the dehacking and packaging process. Additionally, the system would not be part of an integrated package designed for installation in a new plant; instead, it would have to work with the existing equipment in the plant. It would also have to handle a large number of brick—nearly 400,000 king-size units per day—in a less-than-perfect production line.
In the past, these obstacles would have been too much for a robotic system to overcome. But the robots installed in Commercial Brick’s plant feature a unique characteristic that sets them apart from conventional robots—vision.
Taking the PlungeCommercial Brick Corp. was established in 1975 on the site of what was formerly Wewoka Brick and Tile. The new Commercial Brick plant housed a Lingl kiln and produced 25 million king-size face brick per year for the Oklahoma market. Over the years, the company expanded its markets to encompass Texas, Arkansas and a number of other south central U.S. states, and as demand for the company’s products grew, so did the need for additional production capacity. In 1982, the company added a second Lingl kiln and made some improvements to other areas of its plant, but by the early ’90s, the company was once again pushing full capacity. The company’s management decided to begin an extensive investment program to ensure that Commercial Brick could continue to achieve its high quality and production goals.
“Within the last seven years, we’ve spent about $15 million to upgrade our facility,” says Bob Hartsock, the company’s president. “We put in a new monorail system, built three new Lingl kilns and revamped the kiln that was built back in 1975. We also put in a new grinding room, a new manufacturing line and a new setting head. Every change we implemented forced us to improve another area of our production process.”
By the time all of these modifications were finished in 2002, the plant was operating 24 hours per day, seven days per week, and was producing nearly 400,000 brick per day. Every area of the plant was running smoothly and efficiently—except the dehacking and packaging operation, which was still being handled manually from the monorail system.
“As in most plants, dehacking and packaging were the most labor-intensive parts of our process,” says Hartsock. “We were running three 12-men crews per day, seven days per week, and it was becoming increasingly difficult to find 36 people who were willing to do such hard physical labor around the clock. We were also spending a lot of money on labor and employee benefits in that area of the plant. All of these factors drove us to look at robots.”
When Michael Liu and Dan Leeds, local engineering representatives for J.C. Smale, told Hartsock about the company’s new vision-assisted robotic packaging system, Hartsock was immediately intrigued. He and other members of Commercial Brick’s management team visited several plants to see robotic systems in operation. Although none of the systems incorporated the new vision technology, Hartsock was impressed with the quality, durability and safety features of J.C. Smale’s equipment. But it was the price of the system and the company’s expertise that solidified Hartsock’s decision.
“J.C. Smale was very competitive on the price, and we felt like they had the expertise and people on their staff that could make this system work for us,” Hartsock says. “When we looked at the cost of the robots, and then looked at the cost of the labor involved in our existing packaging process, as well as how difficult it was to get people to do that job, it was easy to see how the benefits of the robotic system would make our investment worthwhile.”
Designing for Maximum EfficiencyIn April 2003, J.C. Smale installed a vision-assisted automated robotic packaging system in Commercial Brick’s plant—the first of its kind in the brick industry. The fired product is presented to three unloading tracks and is indexed forward to the dehacking station, which consists of six Fanuc R2000iA six-axis robots. Two robots mounted above each track unload product directly from the kiln cars, where the brick are set in pairs, 12 brick wide by five stretcher-lengths long, 18 courses high. Rather than having the robots sweep the brick along the bedface, J.C. Smale designed a special gripper to pick up the brick between the narrow flue spacing along the bedface direction. This method of gripping reduces the possibility of chipping the brick or disturbing the underlying courses, and it also maximizes unloading efficiency.
Two artificial intelligence vision sensors located on each robot’s end-of-arm tooling enable the robots to “see” the brick and adjust their pickup positions if necessary, rather than relying only on pre-
programmed positions. Tiny cameras located in the vision sensors take two photographs before the robots pick up the brick. The first image is used to determine the theoretical position of the brick. If the brick have moved slightly during the firing process, the robot will be asked to reposition its pick up position. A second image is taken to confirm that the adjustment is correct, and the robots will then proceed to the unloading command. With the vision technology, the robots achieve a 98% accuracy level in picking up the brick. While time is involved in taking the photographs (approximately two seconds for both images), the overall cycle time is significantly reduced compared to manually unloading the kiln cars due to the robots’ consistency in gripping the product.
After removing the brick from the kiln cars, the robots place them on three different put-down positions along a multi-chain conveyor to ensure optimum blending. The system is able to separately grade the bottom two courses, which are more susceptible to thermal cracks, to provide maximum machine efficiency. These courses are manually inspected and are then automatically fed back to the main line for processing.
The product is destacked for one-high inspection prior to the brick passing through the grading area on the conveyors. An employee stationed at each conveyor visually inspects the face of each brick and manually removes those with quality problems. At the end of the conveyors, three transfer heads build the final packs to a height of 12 courses. An automatic paper application system cuts the paper to the correct lengths and applies it to the appropriate course layers. The courses are loaded onto a belt-type lowerator, and two
Signode MHT-80 strapping heads automatically apply plastic strapping to the brick strap, along with edge-protection refrax on all four corners of the cube. The final packs are separated in the strapping tunnel as four straps long and are accumulated on an outfeed conveyor. From there, a forklift is used to transport the packs into the brickyard.
The system is controlled by an Allen Bradley PLC using Control Logix software and is designed to handle an instantaneous rate capacity of 42,000 king-size brick per hour. Two operators monitor the process on a Panelview 1000 touch-screen monitor. Fault banners automatically alert the operators to potential problems and enable them to easily make adjustments to reduce downtime.
The robotic dehacking system also has a number of built-in safety features, which are controlled by a digital Pilz programmable safety system (PSS). The PSS monitors all of the wiring and safety systems for faults, providing redundancy and detailed diagnostics in the event of a system failure.
Learning to Work with RobotsTo ensure that the robots would operate as smoothly as possible, Commercial Brick had to make a number of adjustments in its manufacturing process. “With manual dehacking, we knew that if the hack wasn’t perfect coming out of the kiln, the employees would get it on the monorail. The kiln operators might take a brick off one car to fix the car right behind it—it didn’t matter if we were missing a brick here or there,” says Hartsock. “But with the robotic system, there’s no longer a human being on the other end who’s going to catch our mistakes. Instead, it’s a robot that’s going to go to a precise point, so the brick quality and the hack integrity have to be virtually perfect. It forced us to make a better brick. That starts all the way back in the grinding room—all of the employees know that we need to have a good-looking product in order for the plant to handle the brick efficiently.”
The problem for Commercial Brick and other existing plants is that no matter how many adjustments are made, complete perfection simply isn’t achievable. The new vision-assisted technology enables these plants to reap the benefits of robotic systems even without a perfect process.
“No matter how hard we try, all of our cars aren’t perfect 100% of the time. We’re not a brand new plant, and we don’t have all brand new kiln cars. We continually rebuild our cars and make other adjustments to improve our quality, but when we’re running almost 400,000 brick per day through our kilns, that’s a lot of wear and tear on our cars, and not everything is going to be perfect all the time. The vision technology has allowed us to use robotic technology in our packaging process, despite not always having perfect cars,” Hartsock says.
According to Hartsock, having the right people in place has been key to successfully integrating the new system in the plant. “Aurva Brown, our general manager, James Davis, our plant manager, Ed Davis, head of quality control, and Leonard Dooley, our kiln manager, have all done an excellent job over the past seven years as we’ve upgraded the plant. We felt like we had a very knowledgeable staff, and that gave us a lot of comfort in making this investment,” Hartsock says.
The company also hired Dale Wolf, a computer programmer and electrical engineer, to oversee the robots and other computer-controlled areas of the plant, and it’s been sending some of its employees to a weeklong training session at Fanuc. Additionally, J.C. Smale provided several local support people to oversee the project throughout the installation and commissioning phase.
“It wasn’t like we put the machine in and said ‘I hope it works.’ With the people we already had on staff, and with the addition of Dale Wolf, as well as with the training and support J.C. Smale and Fanuc have given us, we really feel like we have all the tools we need to make this work,” Hartsock says.
The Future of PackagingWith its new robotic packaging system, Commercial Brick has been able to reduce the number of employees in its packaging operation from 36 to eight. The system has also enabled the plant to reduce its packaging time from 24 hours to 12 hours, which allows the company to deliver its products to its distributors much more efficiently. The ability to inspect each brick individually and blend the brick more efficiently is enabling the company to produce better quality packages. And because everyone in the plant knows that the brick have to be an acceptable quality when they get to the end of the line, the company is making a better product overall.
“The savings in labor, along with the notable improvements in production efficiency and product quality, have made this system well worth the investment,” says Hartsock, noting that he expects Commercial Brick to see a payback on its system in just three years.
“Companies in the brick industry have been afraid of installing robots. But the labor force is one of the biggest issues facing today’s brick plants—it’s getting increasingly difficult to keep people who can continually stack brick year after year—and I think that’s really going to force plants to go into robotics. I hope that seeing how our system works will open some doors for other plants in our industry to reap the benefits of this technology,” Hartsock says.
For more information:For more information about the vision-assisted robotic system, contact J.C. Smale & Co. at (613) 9544-7188 (Australia), (214) 458-4642 (Dallas, Texas) or (479) 754-1890 (Arkansas), or visit www.jcsmale.com.
For more information about Commercial Brick Corp., contact the company at (405) 257-6613 or fax (800) 257-6440.