Assembly of aluminum die-cast parts at SUS Corporation in Japan
The company has struggled to find staff willing to carry out the monotonous and repetitive tasks involved in the assembly process. Variations in operator skills have also resulted in production falling below the company’s desired target of one million pieces per month.
Developed using ABB’s RobotStudio® offline programming tool, five robotic cells using ABB’s YuMi dual-arm collaborative robot have been introduced to the production line. The cells have achieved a 20 percent increase in production efficiency, with payback anticipated in around two years.
Headquartered in Shizuoka, Japan, SUS Corporation (SUS) is one of the world's leading aluminum profile manufacturers. With operations in 16 countries, the company designs, develops, manufactures, and sells a range of aluminum products, machinery and equipment for factory automation, control products, and aluminum structural materials.
Since October 2022, SUS has been using ABB robots to make one of its main products, a range of aluminum pipes and connecting components known as the GF, or Green Frame, series. The GF series consists of various diameters of extruded metal frames, each featuring rail-type protrusions down four sides. These protrusions are gripped from the outside by connector parts which are then tightened, resulting in a structure that is extremely easy to assemble and adjust. Using the connectors, frames can be made into almost any structure, ranging from work benches to airport storage solutions and children’s toys.
Over 20 years, the GF family has grown to include more than 40 frame types and over 1,000 related parts, removing the difficulty involved in handling conventionally assembled aluminum frames.
GF's most popular components are the "multi-connectors" made of die-cast aluminum for 28 mm outer frames, available in an inner type and outer type. Because of their frame-snap structure, both types are shipped as a complete product, consisting of two separate parts assembled with bolts. The total monthly production volume of these two types of multi-connectors was approximately 800,000 units.
Reshoring drives production rethink
SUS has been manufacturing these components at its Lamphun Factory in Thailand, as it expands its sales channels around the world. In 2014, the company decided to return to domestic production of key components to improve quality, reduce lead times, and develop its production technology. This would also help it better deal with demand fluctuations and the various risks associated with overseas production.
A particular challenge was the manual nature of the production process. With one worker required for every assembly machine, achieving a monthly production volume of 800,000 pieces needed 11 assembly machines with 11 people working on them full-time. Due to the extremely monotonous and repetitive nature of loading and unloading the machines, the company was finding it difficult to recruit, train and retain workers. There was also significant fluctuation in production volumes due to the varying skill levels of the workers.
Addressing production challenges
It was clear that automation could help resolve these challenges, but there were also several difficulties in putting it to practical use. One of these was the unique spiral shape of the inner-type connector, which is designed to maximize strength when the divided parts are combined. This requires a subtle twisting motion when pre-assembling the divided parts before feeding them into the assembly machine.
Another challenge was the need to accommodate different types of products in the future. SUS also required an accurate preliminary estimate of the effect that introducing automation would have so it could make an informed investment decision on the development of a solution. SUS consulted with ABB to resolve these difficulties and challenges. As a result, the company decided to focus on YuMi®, a dual-armed collaborative robot.
Reaching the right solution with testing and simulation
The automated solution comprises of a YuMi supplied with parts by two rotary feeders placed behind it. The YuMi picks the parts with each arm, places them on jigs, and preassembles the divided parts into an assembly machine. Because YuMi has two arms installed on a compact body and eliminates the need for safety fences, it offers much greater flexibility.
The project started with a simple assembly test of the YuMi at ABB's Local Application Center in East Japan. A simple work environment and jigs were created to calibrate YuMi. By taking advantage of the flexibility of the 7 axes on one arm, it was confirmed that YuMi could combine parts with the necessary twisting action without any problems.
To help guide development, CAD data for the assembly machines and parts feeders were imported into ABB’s RobotStudio® simulation software. A virtual model was created of the actual system layout, allowing developers to optimize the operation and verify production capacity. As a result, it was found that YuMi could achieve the target production volume. The operation of YuMi at different heights was also verified during the simulation, helping to determine the optimal height at which the load is lowest for both arm movements and at which it is easiest to demonstrate its capabilities.
To precisely adjust the program and obtain accurate production volume forecasts in a virtual space, it is essential to achieve a highly accurate match between the actual robot and the virtual robot, including changes in behavior under load conditions. This was achieved by RobotStudio's unique virtual robot controller technology, which operates the virtual robot using the same calculations as the actual robot. The software also enabled simulation videos to be created for the customer's internal approval process, with the programs created during verification also being used as the basic programs for the YuMi robots in the real production line.
“With the introduction of YuMi, it was clear that we would be able to generate sufficient profits. We are now able to stabilize production volumes, which used to vary depending on the skill level of the operators, and we can forecast and adjust production more accurately,” says Nobuyuki Osada, SUS’ Director of Design and Development.
YuMi delivers results
Based on the ROI estimates obtained from the preliminary validation, SUS decided to invest in five automation modules, each incorporating one YuMi.
“The automation has freed the 11 workers engaged in feeding operations from monotonous repetitive tasks and has allowed them to be reassigned to more rewarding tasks such as operation management. The new system has also made it possible to operate at night with fewer workers, with the number of dedicated assembly machines in operation reduced from 11 to five,” says Akihiro Taki, Team Manager, Die-casting Team, Shizuoka Manufacturing Group.
“The time required to feed one assembly machine was reduced from 5 seconds to 4.5 seconds. Similarly, the production volume of one assembly machine in eight hours has increased from 5,000 sets to 6,000 sets, a 20 percent increase in productivity, allowing us to respond flexibly to fluctuations in production volume,” says Masahiro Kawasumi, ECS Facility team. “The payback period for this investment is expected to be approximately two years.”
In the current production facilities, YuMi achieved SUS Corporation’s production targets using only 50 to 60 percent of its maximum capacity, giving extra room to scale up production if needed. Mr. Osada added: “Our engineers made the final adjustments based on the program developed in RobotStudio by ABB’s engineers. This usability will be important for flexible modifications and future expansion during long-term operation.”
In implementing YuMi, SUS successfully automated its manufacturing process with a return on investment that met its expectations. The company is now looking at adding further cells for other types of products and automating other processes.
“We are planning to use this success case as the basis for various production improvements at our many factories,” said Mr. Osada.
To achieve sustainable business growth, SUS has positioned the improvement of production using robots as essential to its plan, alongside the reshoring of its manufacturing.
About SUS Corporation
Since 1992, SUS Corporation has been a leading aluminum profile manufacturer, fully embracing the potential of aluminum and expanding its possibilities by developing and providing aluminum products that support automation and labor saving in various industries ranging from automobiles, semiconductors, and food processing to logistics.
In recent years, SUS has not only provided individual products, such as aluminum frames and components used in production equipment, but has also been helping customers solve their problems by providing solutions, including proprietary controllers that make it easy and inexpensive to electrify workplaces and convert to the IoT. SUS will continue to provide parts and materials using aluminum, a versatile and excellent material, and will also contribute to the provision of services and the promotion of regional industries by taking advantage of the various possibilities offered by aluminum materials.