Local 5G into the Future: Smart Factory

The Summit Steel Osaka Factory is one of the largest sheet steel processing plants in Japan. The factory, located in a gulf region in Konohanaku, Osaka, receives giant coils of sheet steel from steelmakers and cuts and processes them into forms desired by its customers. Processed sheet steel is supplied to electrical home appliance and office automation industries, housing industries, building material manufacturers, and automakers, and is employed in goods commonly used in our daily life. The factory has its own landing facility that can accommodate a 3,000-ton class ship, as well as a large warehouse; that is, the factory is a site for one-stop service, from landing through unloading, storing, processing, and forwarding.

Having never visited a sheet steel processing plant before, I was overwhelmed at the sight of more than hundred gigantic coils being stored there. It is amazing that those gigantic coils require very delicate work. Even a slight impact on the sheet steel can result in a flaw or dent. Such flawed sheets are scrapped and shredded into pieces; therefore, flaw detection is very important in the processing factory.

At a slitting line, where coils are unwound, slit, and cut into narrower strips, field trials were carried out to demonstrate automated visual inspection of surface flaws and remote quality monitoring.

Traditional steps are as follows: The worker visually inspects the in-process coil. If there is a flaw, the worker checks its depth, size, color, and other conditions. The worker takes photos of the flaw and shares them with the head office sales department. Considering the customer’s requirements, the head office sales department decides from the photo whether the product can be shipped or not. If the decision cannot be made on the basis of the photo alone, the sales department staff comes to the factory to observe the flaw.

Local 5G completely changed the traditional process. The 8K line-scan camera used in the automated visual inspection has a high-speed continuous scanning capability and a high inspection accuracy. The camera sends high-definition images of the coil to an AI server via wireless local 5G, and AI determines whether a flaw is present. The location of the flaw in the coil is detected on the basis of transmitted data. High-definition video sent from a 4K camera operated by the on-site worker enables the sales department to monitor quality at the head office. Very small flaws can be identified from a remote location.

Visual checks of very small flaws on coils, which can be a minimum of about 0.3 millimeters wide, had formerly been entrusted to skilled workers. They sometimes devoted themselves single-mindedly to observing coils in a squatting position. Akiharu Kirimura, executive officer, assistant general manager of the Production Division and manager of the Production Control Department at Summit Steel, received positive reactions from on-site workers that their physical and mental burden could be lightened. The staff from the head office required one hour or more to go to the factory and back if an on-site check was needed. Current COVID-19 infection makes it difficult to access the factory. There is an increasing need for remote quality monitoring. On-site problems are expected to be solved by improving safety and productivity, such as reducing the total person-hours needed to complete work, lightening physical and mental burden, and reducing dangerous work required in the vicinity of the running line.

The project requires transmission of high-definition images and video, such as 8K images and 4K video. This requirement can be met by 5G, which is able to transmit a large quantity of data. Cables laid on the floor could be problematic in terms of safety and extensibility, and should be avoided. Local 5G that secures a stable network in a limited region is best suited to tasks that need to ensure a high degree of accuracy, such as automated visual inspections and remote quality monitoring.

In the framework to conduct the field trials, the Sumitomo Corporation Group played a predominant role. Sumitomo Corporation Global Metals was in charge of the problem-solving demonstration and selected the Summit Steel Osaka Factory as the site of the demonstration. Sumitomo Corporation Global Metals is a trading company specializing in steel and has steel processing factories in many locations around the world. Making the most of its rich experience both in the trading business and in managing factories, the company is making positive efforts to promote its own digital transformation.

Takayoshi Suzuki, Digital Innovation Team, Sumitomo Corporation Global Metals, explained the reason that the company participated in the field trials. "We have acquired factory operation data for visualization over a long period of time, so we have been interested in local 5G, which allows the use of high-volume data. Led by the 5G Business Dept. of Sumitomo Corporation, in July 2019, we had an interview. As a part of the project on sophistication by digital technologies at the Summit Steel Osaka Factory which we were implementing at that time, we participated in the demonstration project."

Sumitomo Corporation has been involved in CATV businesses since 1984. Based on close association with cable operators and local regions and findings acquired from telephone, internet, and other communication services, Sumitomo Corporation was able to start its 5G project early. The company has also put efforts into sharing 5G base stations.

The 5G network uses a high frequency band and has small coverage of radio transmissions. Thus, the network requires five to ten times the number of base stations needed for 4G and also requires increased capital spending. Since it is difficult to acquire sites for new base stations in densely populated midtown areas, demand for shared base stations will increase.