UR Cobots Improve Operating Rate at Toyota Motor Hokkaido
01 the short story
Toyota Motor Hokkaido, Inc., which manufactures transmissions, axles, and other parts for Toyota vehicles in Tomakomai, Hokkaido in Japan has "strengthening the manufacturing structure" as a major goal. The company began building a robot system using UR cobots to improve its facilities for the diff-pinion (round gear wheels) loading process, which had been a challenge. As a result, they were able to build their own robot system that reduced costs and space, and improved the operation rate from 92% to 98%, compared to the previous system.
02 the challenge
In the process of feeding a diff-pinion into a processing machine, the operator lifts up a skewer with multiple diff-pinions skewered on it and sets it on the transfer machine on its side, and the workpiece is fed into the machine under its own weight. The equipment had to be modified each time the shape of the workpiece changed, and the skewered workpiece weighed 2 to 3 kg, placing a heavy burden on the operator who had to work carefully to avoid damaging the workpiece.
Video — TOYOTA MOTOR HOKKAIDO, INC, Japan
03 the solution
Junichi Isobe, Head of HEVG Group, Unit Manufacturing Engineer Office, Engineering Department of Toyota Motor Hokkaido, says, "We wanted to improve our own processes based on our goal to strengthen our manufacturing structure, and were introduced to UR cobots by our distributor, Toyoda Yuki. After seeing the growing popularity of collaborative robots at the International Robot Exhibition in December 2019 and the ROBODEX Exhibition in January 2020, we decided to take on the challenge."
The challenge in introducing a cobot for the first time was to keep the cycle time within the prescribed time and to find a way to recognize the workpiece. A vision camera would exceed the cycle time and it would be difficult to detect the workpiece because it is shiny black. Therefore, Toyoda Yuki devised a method that utilizes the UR cobot's built-in force torque sensor (F/T sensor) to detect the workpiece when the gripper hits the workpiece. This method was adopted after a demonstration test. Syusaku Jin, Unit Manufacturing Engineering Department, HEVG, Engineering Division says: "We decided to develop a system without a camera, that simplifies system configuration. The grippers are OnRobot's RG2 and RG6, which are UR+ products, so they were easily programmed on the UR cobot's teach pendant, as well as the cobot’s built-in F/T sensor.”
In the past, operators manually picked a skewer of the workpieces to feed them into a processing machine. The skewered workpiece weighed 2 to 3 kg, placing a heavy burden on the operator who had to work carefully to avoid damaging the workpieces.
UR cobot's built-in force torque sensor (F/T sensor) detects the workpiece when the gripper hits the workpiece.
In the past, there was one material feeder per line, but the UR cobot supplies material to two lines with a single cobot.
UR10e works with operators at the end of a conveyor line.
The UR10e transfers a workpiece and then presses a button to run a conveyor.
Suguru Sakai, leader of Production SectionNo.12, Unit Production Division. No.1, who is in charge of the on-site work, also commented, "If we want to place a workpiece in the opposite direction or change the number of skewers, we can do so simply by reprogramming the robot. The robot also checks the thickness of the workpiece, which I think is very convenient.”
In the past, there was one material feeder per line, but the UR cobot supplies material to two lines with a single robot. Whereas a new material feeder was needed every time a new model was added, the robot programming can now be changed to accommodate the new model, saving on investment. As a safety measure, a safety scanner is installed so that the robot slows down when a person comes close to it, and stops if it is hit by a person. With fewer anomalies, the utilization rate has improved from 92% to 98%. “It is a joy to be able to operate the production line in a very stable manner," says Syusaku Jin.
Jin continues. “The hardest part was the wiring work. I had no experience in such wiring work, so I think this experience will be very useful when we install the next robot. It also helped me improve my skills in electrical drawings for other equipment, regardless of robots.”
UR cobots are also used on the assembly line. Here, the robot is positioned at the end of the conveyor where people are lined up, and is responsible for transferring the workpiece to the next conveyor. The advantage of this system is that even if a problem should occur with the cobot, it is possible to return to human work and not have to stop operation.
Toyota Motor Hokkaido hopes to introduce UR cobots in various processes in the future. “Of course, decreasing system cost is one of the keys in strengthening the manufacturing structure. However, on top of that, working on various projects is the way we can improve our own skills. I believe that this is one way to strengthen our manufacturing setup,” says Isobe.
- Robot introduction has resulted in a 98% process utilization rate.
- Built a cobot system without a vision camera by utilizing the built-in F/T sensor.
- Easy to learn programming
- Deployment done in-house without external experts
- Loading workpieces into processing machines
- Transferring workpieces to a conveyor
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Cost-effective, safe and flexible collaborative robots - or cobots- are making automation easier than ever, even for the small and mid-sized companies.