Headquartered in Shizuoka, Japan, SUS Corporation (SUS) is an aluminum profile manufacturer. 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.
In October 2022, SUS began using ABB robots to make 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 easy to assemble and adjust. Using the connectors, frames can be made into almost any structure, ranging from work benches to airport storage areas and even children’s toys.
The GF series’ 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 is approximately 800,000 units.
Reshoring drives reconsiderations
In 2014, SUS decided to restore domestic production of key components to improve quality, reduce lead times and develop its production technology. This would also help the company better deal with demand fluctuations and the various risks associated with overseas production.
One challenge to this reshoring initiative 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 required 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 found 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.
It was clear that automation could help resolve these challenges, but there were also several difficulties when it came to automating the GF series production. 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.
After consulting with ABB, SUS chose YuMi, ABB’s dual-armed collaborative robot to automate portions of the GF series assembly.
Subhead: Testing and simulation
The automated system at SUS includes a YuMi robot supplied with parts by two rotary feeders situated behind it. The YuMi picks the parts with each arm, places them on jigs and preassembles the divided parts into an assembly machine.
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 seven axes on one arm, it was confirmed that YuMi could combine parts with the necessary twisting action.
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.
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 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…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,” said Nobuyuki Osada, SUS’ director of design and development.
Cobot application results
Based on the ROI estimates obtained from the preliminary validation, SUS decided to invest in five automation modules, each incorporating one YuMi.
Automating these processes has “freed the 11 workers engaged in feeding operations from monotonous repetitive tasks and 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,” said Akihiro Taki, team manager, die-casting team, Shizuoka Manufacturing Group (SUS Corporation’s Shizuoka site).
According to SUS, 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% increase in productivity, allowing the company to respond more flexibly to fluctuations in production volume.
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%-60% of its maximum capacity, giving extra room to scale up production if needed.
“We are planning to use this success case as the basis for various production improvements at our many factories,” said Osada.