Nissan Passionate Challengers


Manufacturing cars to make everyone smile


The Tochigi factory, responsible for mass production of the Nissan Ariya, has incorporated a new concept that has never been seen before―the Nissan Intelligent Factory (NIF). The introduction of innovative production technologies based on this concept has made it possible to mass produce the Nissan Ariya. The representative technology of NIF is the Powertrain Integrated Mounting System called "SUMO; Simultaneous Underfloor Mounting Operation." We interviewed Takeshi Shimada (Vehicle Assembly Engineering Department, Vehicle Production Engineering and Development Division), who was in charge of developing and introducing equipment including SUMO, and General Foreman Atsushi Akiyoshi (Assembly Section, Manufacturing Department No.1, Tochigi Plant), who organized the assembly process of the production site.

Takeshi Shimada, Vehicle Assembly Engineering Department, Vehicle Production Engineering and Development Division

General Foreman Jun Akiyoshi, Assembly Section, Manufacturing Department No.1, Tochigi Plant

Automation significantly reduces the burden on workers

Akiyoshi: In the process of assembling the powertrain and suspension to the body, the body is suspended from above and the parts are held up from underneath and secured with bolts. This inevitably means that the work is done while looking up. Also, the bolts are very long and require strong force to tighten them, so the special tools are heavy. Since the work must be done while holding up these heavy tools, the process was tough for people who are not so strong, such as older workers or women. In addition, the plant is lit from above, which creates shadows and makes it difficult to pinpoint the places for the bolts.

Shimada: SUMO system instantaneously measures the position of the body through image recognition by a high-speed vision system. Our pallet system and automatic assembly robots that were developed in-house have made it possible to assemble the motor, battery, and rear suspension in one go. The mounting of three units, which used to be divided into six processes, has been consolidated into one very versatile process. Even the burdensome work of tightening the unit while looking up has been fully automated.
The process starts from when workers first assemble the powertrain components on three pallets (jigs to set the components in the correct position) at the front, center, and rear of the vehicle. The robot then moves the pallet based on the measurement results and automatically assembles it in the correct position on the body. By changing the units that are placed on the pallet, it is now possible to produce gasoline-fueled vehicles, e-POWER-equipped vehicles, and EVs all on the one line. It is a revolutionary system that supports 27 different combinations of modules for each platform. This eliminates the need to work in strenuous positions and allows the operator to concentrate on the assembly work, thereby contributing to the stabilization of quality.
When introducing the system, one of the challenges we faced was the requirements for vehicles and parts. In order to enable robots to perform automatic assembly while accommodating a wide range of vehicle types, it is necessary to consider from the design stage. We have defined the requirements including those of Renault, we can reap the benefits of universal mounting in the alliance, and now it is possible to implement it in other factories as well.

Simultaneous underfloor mounting by SUMO

Bringing the robot closer to mastering expertise

Akiyoshi: When I first heard that SUMO was going to be introduced, I was eager to adopt it because I thought it would greatly reduce the burden on workers, but I was also wondering can robots really master the expertise of skilled workers. What’s great about humans is that we can make fine adjustments according to the situation. The position of the vehicle body moving along on the production line is not constant, and deviations of millimeters can occur, so each unit is judged individually as it is worked on. I thought it would be difficult for a robot to reproduce that kind of fine adjustment.

Shimada: The vision system that keeps track of the body’s position in millimeters is the vital part of SUMO, but as we made more and more prototypes, we realized that there could be a subtle margin of error depending on the color paint used.
We asked our colleagues in the painting process to help us create test pieces with part of the body painted and adjusted the vision system by attaching the test piece to the body of a different color.
Another difficult part was the roof trim, which is the lining of the ceiling of the vehicle. This is used for noise absorption, sound insulation and thermal insulation, and is attached with clips instead of bolts. Automated technology has been established for tightening bolts, but there was not yet sufficient technology for clips.

Akiyoshi: If the clip is pushed in too hard, the headlining itself will wrinkle, and if it is pushed in without the holes being aligned, the clip will get damaged. Above all, it is difficult to control the right amount of force, and it requires careful and precise workmanship.

Shimada: Basically, we attach a pressure sensor to diagnose if the clip is locked, but since each clip has a different shape, the change in pressure when a clip lock is not uniform. The pressure will also vary depending on the position of the clip. After much experimentation with each clip to find out where to press to get an accurate grasp of the pressure change, the automation process was finally stabilized.

Roof trim

Manufacturing cars from Tochigi to worldwide and make everyone smile

Shimada: It was the first time for me to be involved in installing such a large new facility, but my past experience helped me a lot. The experience of installing equipment in a mass production plant is what helps me out when I am faced with a problem. What problems will become apparent in mass production? How can they be resolved? The know-how I gained from my past experience was useful from the development stage. As for the vision system, there was a case where it was utilized when Nissan Motor Kyushu adopted a facility to automatically combine the engine and transmission, and all the difficulties that I experienced then have helped me out now.

Akiyoshi: We are all very proud of the fact that we will be able to assemble the Nissan Ariya, Nissan’s flagship model, with the most advanced production equipment ever built. All the workers have a positive attitude, and we can feel the commitment from each person to build the Nissan Ariya with high quality.
One of my favorite sayings is, “Have the courage to go to places where you don’t feel at ease.” If you want to take on new challenges and grow, you have to go to places where you don’t feel comfortable. I told the Tochigi Plant’s foreman these words, and I believe that we were able to proceed with the project while sharing this kind of spirit with everyone. There have been many changes, but at each milestone, someone has always taken on the challenge. That is Nissan’s DNA.

Shimada: The introduction of NIF is going to change the entire plant. In recent years, the number of workers at production sites is also decreasing. There is an even greater need to create workplaces where everyone can work comfortably, including women and older people. By incorporating automation, as in this case, the burden on workers will be reduced, and we will be closer to a workplace where everyone can work comfortably.

Akiyoshi: In the assembly process, I have been saying, I want to make everyone smile through the Nissan Ariya. I want to make not only the Ariya project members, but also the suppliers and distributors, and most of all, I want to make the customers smile. We will continue our efforts to make the Tochigi Plant and other Nissan plants even better.

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