Improved environmental performance through stabilization of recycled sand properties and reduction of waste materials
EXEDY Casting Co., Ltd.
Fukuchiyama City is a town where various minerals were produced and has always been a hub of commerce and industry. Even today, it has one of the largest inland industrial parks in Japan, which is home to a large number of companies. Established in 1968, Kinugawa Cast Iron Co., Ltd., has mainly produced castings for industrial machinery, and became a subsidiary of EXEDY Co., Ltd., an automotive parts manufacturer, in 2008. At present, the company manufactures transmission cases for industrial vehicles and drain pipes for housing complexes under the name EXEDY Casting Co., Ltd. (Fukuchiyama, Kyoto）.Pictured are President,Kazushi Imaru(middle), Director,Hiroki Honjo(right), Gen Kinugawa(left)
Desired quality and introduction of new methods
In recent years, the production volume of castings in Japan has declined in line with growing competition from overseas companies. Evaporative pattern casting employed by EXEDY Casting, which uses a pattern made from polystyrene foam, is suited to high-mix, low-volume production, and has continued to meet domestic demand in Japan owing to its short lead time.At one point, however, we were faced with the problem of an increasing rate of product defects. It was at this time that Kao-Quaker introduced us to EG Runner. EG Runner is made from recycled pulp instead of ceramic used for conventional runners (tube through which molten metal passes to form the casting).Normally, changes in the manufacturing process place a heavy burden on employees, but EG Runner was particularly popular among our veteran employees because it was easy to cut into different lengths and generated little dust when it was cut. In addition to the enhanced workability, we also made a variety of other improvements and succeeded in significantly reducing our defect rate.
Working towards the establishment of more environmentally friendly plants
In 2015, our new plant, Plant 0 (Zero) commenced operations with aim of reducing defects to zero. Various efforts are being made to improve the working environment. Plant manager, Kinugawa speaks about how dust collectors within the plant are adjusted to ensure they maintain above-standard performance and how consideration is also given to noise levels. "I would like to make this a no mask plant in the future. Once COVID is over, I would like to see people working in here with no masks," says Plant manager, Kinugawa.
Contributing to the stabilization of recycled sand
The vacuum casting method, in which the sand used as the material for the mold is reduced in pressure using a vacuum pump, does not use binders, so no additives are added to the sand and no crushing is required, reducing the amount of gas release from thermal decomposition and waste materials. In the past, when a shell tube was used as the runner, the problem was that debris from the shell tube remained and the particle size of recycled sand became unstable.One measure used to counter this problem was to increase the power of the dust collectors, however this generated a large amount of sand waste. "EG Runner is carbonized after the pour, and is sucked up by the dust collector, leaving little debris in the recycled sand, helping to stabilize the properties of the sand. This has also helped to significantly reduce the amount of waste generated," says Director, Honjo.
Commitment to quality improvement
Because a specific level of permeability can be maintained when the properties of recycled sand are stabilized, we were able to significantly improve product quality. "When using shell tubes, gas was generated when the pour cup was re-melted, resulting in the generation of slag caused by burn-on. Although the products made by EXEDY Casting are not directly visible to consumers, it is better to deliver a product that looks good to customers who actually use the products, even if the performance is the same," says Director, Honjo, who takes onboard customer feedback and pays close attention to product quality.
Passing on skills and introducing new technologies
EXEDY Casting currently employs 68 people. This includes 15 Vietnamese trainees who are here to learn more about Japanese technology. While veteran workers from the generation of baby boomers are retiring, the impact of Japan’s declining birthrate is the same for the casting industry. Furthermore, considering the transfer of skills to trainees from overseas, we believe that it is essential to actively introduce mechanization and new technologies to maintain and improve quality.