ASICS produces shoes for many of the world's top athletes. The Custom Production Department of the Footwear Production Division, which is responsible for producing these shoes, has introduced Gravio to improve the assembly line in low-volume production. This work tends to have both a high degree of customization as well as manual production steps. Introducing Gravio was the first step towards realising the company's goal of a carbon-free society by breaking away from intuition and experience, improving quality and productivity, and eliminating waste in production, creating a model factory for sustainable footwear production.
Mr. Hagihara: The Custom Production Department of the Footwear Production Division at ASICS produces sports shoes for athletes. We produce a large number of shoes for domestic and international athletes, including top athletes who participate in international competitions.
Unlike sports shoes for the general public, the shoes we produce here are specially designed for each athlete. We only make a few pairs of those custom shoes for each athlete at a time as they are tailored specifically for them.
In our medium-term management plan, we have set out to "shift to digital management" and "achieve a sustainable society through our business activities", but as our production is mainly bespoke, there have been a number of challenges in pursuing efficiency through digitalisation and establishing sustainable processes that reduce waste as much as possible. It is also a fact that there have been many challenges in establishing sustainable procedures that reduce waste to the utmost minimum.
Sakai, who is in charge of the production site, suggested that we should use digital technology to improve the efficiency of the site. There are some processes that it would be difficult to introduce technology into due to the high level of human resources needed, and that quality is maintained by experience, but there is a lack of accumulated data throughout.
Sakai told us that there was a cost-effective, small-start system that could be implemented. That was Gravio.
Mr. Sakai: When I joined the company, I was assigned to the same site as I am now, where I was involved in the production of shoes, but for a while I was also assigned to a department related to production engineering at head office, where I learned various concepts about production improvement.
When I came back to the production site, I was always looking for ways to improve. We decided to start by looking for an IoT system to control the temperature of the equipment that heats and bonds the upper part of the shoe (where the foot enters) to the sole. However, we decided that retrofitting the sensors to the equipment would be costly and the sensors themselves would be too expensive for an experimental project, so we decided against it.
I was introduced to Gravio by a technical staff member who I had met at head office. I was convinced that I could persuade my boss to start with a plan that cost $5 USD a month, so I submitted an application and was able to start with a trial project.
Mr. Sakai: The first thing we did with Gravio was to control the temperature on the equipment that heats the soles and the upper parts of the shoes. We used to measure the temperature twice a day with an analogue thermometer to make sure it was at the right level to run the equipment, but after Gravio was introduced, we installed temperature sensors on the conveyor belts where the drying takes place, visualised the data using a cloud-based BI tool (Google Data Studio) and shared daily temperature change reports with the relevant staff members via email.
Mr. Hagihara: What surprised me when we started was the variation in temperature change. Of course, it was within the permissible range, but the temperature change was much larger than expected. This temperature control is important, as it determines the quality of the adhesion i.e. the strength of the upper part of the shoe and sole, which will not peel off when used in the real world.
In recent years, due to environmental concerns and changes in the composition of adhesives, temperature control has become more stringent than before.
However, by using Gravio, we are able to see the minute changes in temperature and can adjust the settings to better suit our needs and to be closer to acceptable levels. This is a first step in the right direction.
Mr. Sakai: Yes. The next step in using Gravio was to expand the temperature control of the drying equipment; we added a system where the Gravio light turns red to notify people if the temperature is out of the acceptable range. Before the lights were installed, it was necessary to check the temperature status by looking at the PC screen, but now the lights are green when the temperature is within the permissible range and red when it is outside the range, so it is easier to notice issues from a distance.
Mr. Hagihara: This is not just about communicating abnormal values quickly, it is also beneficial for managers like myself. We don't have to look at the PC screen or go near the equipment, we can just look around and see what's going on, so we feel that the management overhead has been reduced.
Mr. Sakai: The next thing we tried to visualise with Gravio was the time it takes to complete a process. This is done using Gravio's double button. By pressing the start button at the start of the process and the end button at the end of the process, each timestamp is sent to a spreadsheet service in the cloud, and the task duration (process working time) can be easily calculated and graphed. At first the staff tended to forget to press the buttons, so we added a Gravio notification light to remind people to press them, which worked very well.
Mr. Hagihara: On a mass production line, task time can be measured by a production engineer with a stopwatch, or by installing automatic measuring switches and sensors on the line, but on a small production line like ours, we can't invest in this kind of equipment. Gravio makes it easy for us to achieve this.
Mr. Sakai: By this point, the number of sensors needed had increased and the Basic plan ($5 USD per month) was no longer sufficient to cover our needs, so we had to upgrade to a larger grade. We had seen what Gravio could do, and its benefits, so we were able to get approval.
Mr. Sakai: The next step in using Gravio was to create a system that uses motion sensors to notify upon completion of the drying process by another heating device.
When the sole has finished drying, a motion (heat) sensor detects this and turns on the Gravio light, allowing the user to see when the process is complete by looking at the equipment.
The next application of Gravio is to control the temperature and humidity in the material warehouse. This is where we store meshes, natural leather and soles for the upper parts of the shoes. We used to have an analogue thermometer here, which we checked twice a day, but it was only an 'as-is' temperature/humidity gauge and we couldn't keep track of temperature changes throughout the day.
So we installed Gravio temperature and humidity sensors, and sent the data to a cloud-based BI tool (Google Data Studio) to visualise the temperature changes.
Thanks to the cloud service, we are now able to check the temperature and humidity changes outside the workshop, which means that we can check the warehouse environment even when working from home during the Covid-19 pandemic and react quickly to any abnormalities.
We also installed Gravio temperature and humidity sensors in the facilities where the soles are pre-processed. The soles are scraped with wire brushes and there is a wire mesh under the workbench to absorb the shavings. It is therefore necessary to control the temperature and humidity using air conditioning equipment at all times. We used to have an analogue temperature and humidity meter, which we checked daily, but this has been replaced by a Gravio temperature and humidity sensor, which measures the humidity at all times, and if the humidity exceeds the standard value, the Gravio light turns blue to notify the team about humidity issues.
Mr. Sakai: In March 2021, we implemented a system for measuring the thickness of soles and other components of shoes using distance sensors with laser light.
There has been a lot of talk about sole thickness recently. Wrong sole thickness can even lead to disqualification in competitions. It is now more important than ever to measure the sole thickness accurately. We measure the sole thickness of our shoes in order to ensure the appropriate functionality and that athletes can use our shoes with confidence.
In the past, we used callipers to measure the soles, but it took 5 minutes per foot to measure with callipers, and in order to measure the elastic soles accurately, we had to apply the measuring devices with great care so that no force was applied to the soles. However, as the amount of force applied varies from one person to another, we had to double-check the results. In addition, the post-measurement process was complicated, with measured values being written by hand and input into a PC.
When the distance sensor was released by Asteria in January 2021, we immediately set up a measurement system. The new measurement process now only takes 20-30 seconds. In addition, the measurement is automated due to the sensor using laser light, which eliminates the variability between different people taking measurements. The measurement is initiated by reading the barcode on a unique tag attached to the shoe, and the measured sole thickness of both feet and the individual identification number of the shoe are added to the management sheet, which can be linked to the athlete's medical record data to trace the work process. In other words, this system has achieved traceability while increasing measurement efficiency and accuracy.
Mr. Sakai: Yes, we have tried many ways. One case that didn't work for example, was when we tried to put a Gravio vibration sensor on a sewing machine to get data on the operating rate, task time and so on, but we couldn't get any useful data, so we didn't continue pursuing this.
I think one of the advantages of Gravio is that you can easily do this trial and error. It's not easy to say "no" to a standard IoT device when you consider the cost and installation effort.
Mr. Sakai: Asteria has helped us in many ways since the introduction. They don't just provide a service, they catch up with what we want to achieve and help us to achieve it. In addition, the system is very easy to use and can be flexibly integrated with the latest technologies such as cloud-based BI tools and spreadsheet services.
Mr. Sakai: At the moment, we have not yet been able to make use of the data we have accumulated, but since the start of operations of the year, we have gathered a lot of data on the manufacturing conditions of each shoe.
In the future, we hope to use this data to analyse and prevent defects in the manufacturing process and to narrow down defective batches.
Mr. Hagihara: By accumulating the manufacturing conditions of each individual product, we feel that we have been able to prevent defects from occurring in the manufacturing process. I think that by analysing the accumulated data in the future, it will become possible to trace defects and determine trends.
As the data that Gravio collects helps us to improve quality, we can reduce material waste and energy by reducing the number of defects in the manufacturing process. It's difficult to make a big impact at this site because of the low volume of production, but if the work done here could be replicated in a mass production plant, it will be possible to reduce a lot of waste.
This is in line with our current medium-term management plan, which calls for a "shift to digital-based management" and the "realisation of a sustainable society through our business activities".
We are convinced that Gravio will contribute in a large way to the athlete-friendly, carbon-free society we are aiming to achieve.
"Gravio, with its small start, is the perfect IoT solution for this particular production line, which produces a wide variety of products in small quantities. We are looking forward to demonstrating a variety of IoT applications to eliminate waste, which will be rolled out to mass-production factories in the future, and which we hope will become a driving force behind ASICS' goal of realising a sustainable society."
"The beauty of Gravio is that you can do new things without hesitation. Because of its low cost and high degree of freedom, we can try different approaches through trial and error. We are confident that we are creating an environment where we can find ways to improve quality and productivity and reduce waste, and where we can use the data we collect to make new improvements."
ASICS Corporation, Footwear Production Division, Custom Production Department
1-1, Minatojima-nakamachi 7-chome, Chuo-ku, Kobe 650-8555, Japan
The company's name derives from the Latin phrase "Anima Sana In Corpore Sano" (A sound mind in a sound body), a philosophy that has remained with the company to this day. Today, ASICS is a leading designer, developer and manufacturer of running shoes, athletic shoes, sportswear and accessories. The Custom Production Department of the Footwear Production Division manufactures shoes for a wide range of domestic and international athletes.