Production of the popular Japanese ice cream brand Yukimi Daifuku recently underwent a major process upgrade, with the introduction of Mitsubishi Electric’s e-F@ctory concept delivering enhanced quality and consistency, and improving overall efficiency.

Since its launch in 1981, Lotte Corporation’s Yukimi Daifuku has been a popular Japanese household favourite that is loved by people of all ages. Many have tried the unforgettable flavour and texture of the vanilla ice cream balls wrapped in soft, chewy mochi rice cake, regarded as “Delicious whenever eaten, regardless of the season”.

However, to achieve that deceptively simple goal of consistent texture, quality and taste is actually more difficult than most people would have thought. To solve this challenge Lotte has introduced Mitsubishi Electric’s e-F@ctory to the production of Yukimi Daifuku. e-F@ctory is Mitsubishi Electric’s integrated concept to build reliable, flexible manufacturing systems that enable users to achieve high-speed, information-driven production.

“Before introducing e-F@ctory, there was an issue of inconsistency of the rice cake quality,” said Hiroshi Sugimoto, Manager of the Facilities Department at Lotte Corporation’s Urawa plant. “When wrapping the ice cream, the hardness of rice cake used to vary depending on the temperature and water content. Some operations were dependent on people, and losses arose out of the need to finely adjust the machine parameters.

“The e-F@ctory system allows us to conduct improvement activities such as enhancing the operating rate, stabilising quality, and optimising staffing for production activities. The extendibility of the system, depending on what we want to do, was also appealing.”

At each of the Yukimi Daifuku production lines the state of the product and the operating status of the machines is collected by programmable logic controllers (PLCs) installed in each process. Vast amounts of data, such as vibration data from the rice cake hopper, or data from the conveying inverters, is collected. All of the data can be understood in real time, not only through the overall SCADA (supervisory control and data acquisition) monitoring system, which is installed in the control room, but also through on-site computer displays.

“By introducing this system, data became centralised, making it possible to view and investigate conditions whenever we want,” remarked Hiroshi Akimoto, Section Manager of Facilities Department, at Lotte’s Urawa Plant. “Because the data volume is extremely high, having all the data centralised in one place has a positive effect. One big benefit is that we can now gather and analyse data and conduct data diagnostics using a real-time data analyser. This system not only helps us stabilise the state of the rice cakes used for the Yukimi Daifuku, but also promotes improvement activities within the plant.

“Another benefit is the adjustment of the blending ratio of rice cake and ice cream,” Akimoto adds. “This was usually done by experienced operators, who monitored the state of the rice cakes as they come out of the wrapping machine by kneading them with their fingers. We thought it would be great if we could automate this process. By automating such processes, which were conventionally performed based on human senses, and by capturing signs of any poor quality of the wrapped rice cakes beforehand, we can eliminate problems. That was our ultimate goal.”

Takayuki Manako, Executive Director & Plant Manager at Urawa, remarks on some of the manufacturing challenges that his team faces: “As you know, ice cream is a cold material. This cold ice cream is combined with rice cake, which is warm when it is made. This technical aspect of combining a cold item with a warm one in a good balance is what makes Yukimi Daifuku a complex product. But I think this challenge is something that inspires us to find new ways to overcome it.”

“The temperature in the manufacturing room varies all year round. We strive to maintain consistent conditions, but at the same time, we try to reliably create even better conditions. We introduced the e-F@ctory manufacturing concept with the expectation of realising this in the future.”

Manako explains how, in the course of daily production, machines do not operate in the same condition every day. To remedy this in the past, experienced staff members would have checked and adjusted the settings of the machines. However, with e-F@ctory it is possible to visualise the condition of machines, and indeed the machines themselves can issue instructions to make adjustments. In addition, while maintenance and failures remain unavoidable with machines, the team at Lotte anticipate they will be able to manage these issues more effectively using e-F@ctory’s symptom management features.

“The use of the Internet of Things (IoT) has only just been introduced to the production of Yukimi Daifuku,” Manako adds. “However, the Urawa plant has many other lines making chocolates and ice creams, so Yukimi Daifuku is not our only challenge. We aim to horizontally deploy this system and construct a smart plant in which ‘symptom management’ and ‘operating rate improvement’ are implemented on numerous lines. Stable plant operation and manpower savings will eventually make a major contribution in terms of costs and so on. If we consider Lotte as a whole, our goal is to further evolve this technology and extend it to other plants.”