UR3 cobot automates quality testing at Koyo Electronics

Koyo Electronics Industries has been involved in the development, manufacturing, and sales of electronic equipment since its establishment in 1955. It is also a member of the JTEKT group that boasts the world’s top share in the automotive steering bearings.

Challenge

In the production of products that require strict quality, such as the main product of in-vehicle electronic devices, PLCs acting as the control tower for machine control, and rotary encoders, the challenge for Koyo has become how to increase productivity according to increase in demand.

The first thing Koyo worked on was a review of the panel computer inspection process. In the pre-process, operators perform product assembly and visual inspection, and in the post-process the operators apply styluses to the touch panels to confirm the devices react as intended.

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“Traditionally, three people were performing the series of work,” said Katsuhiko Nakatani, Deputy General Manager of the Production Department. “As there were some bottle neck processes, we reallocated some of them which resulted in the balance between the pre-process and the post-process being lost. So, we examined the implementation of a UR cobot to improve the productivity of the post-process.”

Solution

Koyo installed a UR3 cobot from Universal Robots (UR) to improve productivity. The UR3 was introduced in the touch panel quality inspection process. When the UR3 touches the touch panel with a stylus, “OK” is displayed if there is no quality error, and the green signal of a signal tower lights up. When an abnormality is detected, “NG” is displayed on the display, the red signal tower lights up, and the buzzer sounds continuously. As a result, the person in charge immediately notices the abnormality and can respond.

Koyo first learned about cobots in 2017. “A proposal was made by Inaba Denki Sangyo Co., Ltd., an official distributor of Universal Robots,” Nakatani. “As the robot is lightweight and space-saving, we didn’t need to make a major layout change and considered implementation.”

The fact that the UR3 could be installed without a safety fence was a decisive factor.

“We conducted risk assessments in accordance with our company’s safety standards and worked on ensuring the safety of workers. At the beginning of implementation, we made certain adjustments such as speed reduction as the staff was afraid of moving the robot at high speeds,” said Atsushi Fujita, Chief in the Production Technology Department “As the cobot works with higher accuracy and stability than humans, the quality of the work improved as a result.”

It took three months from the delivery of the robot, to the system design, setup, testing, solving various problems, and operation on the line. The hardest part was connecting the UR robot to external devices such as a PLC and a PC.

“It took about two weeks of trial and error, but we finally could build our own system that does not depend on any external resources, such as SIers,” Fujita said. In addition, the part that allows the cobot to hold the jig was improved. At first, it did not work properly because the jig was heavy, but they finally managed to make the jig easier to hold through repeated fine-tuned adjustments.”

Case Study at a Glance

Results with UR3

According to Koyo, the UR3 has reduced the daily work time from an average of 10 hours to 8 hours. It also helped increase productivity 31%.

“Humans tend to make mistakes when working with a touch-panel system, and we are happy to have cobots to do this work accurately and complete the task properly,” Yuki Oshiba, who runs the inspection process. “Since our job was only to press the ON/OFF button, we can now do other duties while the robot is working, making the system very productive. When there is an abnormal shut-down, an alert is issued, and the person in charge of production technology will come by, so we can rest assured that no interruptions in production will happen.”

Koyo said the return on investment would be one year. It is now considering using cobots for other processes.

“For example, in the substrate processing process, we are examining whether it can be used for sending the substrate that has completed a process to the next process. By implementing the UR cobot, the number of post-inspection process personnel was reduced from two to one,” said Nakatani. “Not only has our company been able to improve productivity by allocating resources to another production process, but the experience from implementing this robot has built confidence and high hopes for future development.”