The power used by the manufacturing industry accounts for approximately 45% of the total power usage in Japan. To reduce this manufacturing industry’s power usage, each factory has worked hard to promote energy conservation. The Great East Japan Earthquake spurred the demand for greater energy-saving efforts throughout Japan.

Conventionally, each production site promoted various energy conservation measures such as replacing machines with more energy-efficient types, turning off lights and equipment when not in use, and so on. More environmentally conscious companies have adopted a system for monitoring power that is used by each piece of machinery, locating wasted power to reduce overall power usage. A radical transformation of our way of thinking is needed to cut power usage even more substantially.

Energy-saving measures that each factory conventionally promoted had a "blind spot," according to Takashi Otsuka, general manager of the Advanced Sensing & Control (ASC) Business Division of OMRON’s Industrial Automation Company. "It was excessive power consumed for the sake of maintaining product quality," he says. By implementing all possible measures, Japan’s manufacturing industry is well known for their top-level efforts for reducing energy usage in the world. Even so, Mr. Otsuka and his team thought that there might be more areas where energy is wasted, and gave further insights into various points. As a result, they found that there were many cases in which machines for maintaining product quality are operated more than necessary.

For example, in a workplace where precision components are produced, even a tiny bit of dust and airborne particles can adversely affect product quality. In many cases, fan filter units (FFUs) are constantly kept in operation in order to maintain a clean environment. But in fact, it wasn’t clear whether full operation of FFUs is really necessary to ensure the high quality of a product. Formerly, manufacturers were unable to stop operation of FFUs because they were afraid that even momentary stoppage may cause a quality problem. (Figure 1)

Mr. Otsuka and his team realized that OMRON’s sensing and control technologies can be relied on to address this issue. They came up with the idea of operating an FFU only when it is necessary and as long as it is necessary by controlling the FFU. It works by precisely checking the air’s cleanliness levels and analyzing the conditions in which particles increase in volume.

［Figure 1］ Key Point for Energy Control

To verify the feasibility of this idea, the ASC Business Division’s Development Department staff installed OMRON’s particle sensors on various locations on a precision component production line, in order to thoroughly investigate factors that cause particles to increase. As a result of this investigation, it became clear that the amount of particles increased only when a certain piece of equipment was in operation. It was in fact not necessary to keep FFU in operation all the time when that equipment piece is not in operation.

Based on this finding, the Development Department staff broke down the relationship between changes in the amount of particles and the equipment’s operational status into various patterns. The staff then developed a system for optimally controlling the FFU’s operation. The system uses a sensor to detect even a minor change in the amount of particles, and turns up FFU’s operation if an increase of particles is anticipated, and vice versa. Deployment of this system helped enhance production staff’s consciousness for keeping worksite environment clean, resulting in an implementation of improvement measures for the equipment itself (a source of particle increase) and thorough cleaning efforts. Consequently, the worksite that adopted the system was able cut power usage by FFUs by 40 percent while at the same time enhancing product quality. (Figure 2) Surprisingly, this workplace was inside the factory, which has consistently taken the lead in implementation of energy-saving measures. OMRON was able to make this achievement because the company itself is a producer of high-precision components. Mr. Otsuka stresses the importance of this point. "For the future, our customers will not employ any system unless we can verify that it will not adversely affect the quality of their products. Our real strength is in our capability to conduct verification tests at our own factory under exacting quality control. I believe this capability leads to the trust we earn from our customers."

At manufacturing sites, many pieces of equipment are in operation for controlling heater temperature, flow of cooling water and compressor air pressure along with cleanliness of air. "Among these equipment pieces, I’m sure that there are many that are in fact operated more than necessary. By keeping the operation of these equipment pieces at the bare minimum, production sites can save even more energy. I believe this is what will be in demand not only in Japan but also at the rest of the world as well," concluded Mr. Otsuka. OMRON has again launched a new challenge of accelerating energy conservation efforts of the global manufacturing industry.

［Figure 2］ Power Usage by FFU

［Figure 2］ Amount of Particles within the Clean Booth