As technology experts, our history at SJM Co., Ltd. is shaped by an innovative tradition that is enriched by inspiration and by researching new products and processes.


Established in 1975, Sung Jin Machinery (now SJM) was the first company to establish bellows production in South Korea. SJM developed and produced phosphor bronze bellows, stream traps, and expansion joints for industrial plants. In 1979, Sung Jin Machinery outgrew its initial location and moved the main office and the factory to Ansan City, Kyungki-do, South Korea where the company Headquarters and two manufacturing plants still operate.


In 1980, Sung Jin Machinery was approved as a manufacturer of expansion joints used for ships, from American, British, and Norwegian certification bodies. In 1982, Sung Jin Machinery earned the Korean Standard (KS) mark for its construction expansion joints. During the 1980s, Sung Jin Machinery continued its successful formula of making industrial bellows and applied its technical capability to the automotive industry and in 1985 supplied its first automotive flexible coupling to Hyundai for the X-Car exhaust system. That milestone quickly shifted SJM's focus to be a formidable competitor in the global automotive marketplace.


The 1990s proved to be a rapid advancement and growth period for SJM. Though continuous investment in technology development, SJM began production of Q-class expansion joints for nuclear power plants in 1990. Sung Jin Machinery secured its position as an international manufacturing company establishing SJM FLEX (M) SDN, BHD in Malaysia as a joint venture with PNB and UMW of Malaysia in 1991. In 1995, SJM founded a technology research center. In 1996 Sung Jin Machinery officially became known as SJM and began trading stock as a publicly traded company on the Korean Stock Exchange in 1997. Also in 1997, SJM Flex SA and a joint corporation CSA were established in South Africa, as well as the opening of SJM GmbH, a European Sales and Engineering office located in Germany. In 1996 and 1997, SJM earned ISO 9001 and QS 9000 certification confirming to the company's customers that SJM's quality systems support or exceed their expectations.

2000s till now

The 2000s are becoming the next generation of rapid growth for the company strengthening its position as a global corporation and diversifying its business interests. In July 2001, SJM established SJM NA Inc. in the U.S. as a compliment to its existing global network and to provide localized support to its international customer base. In 2002, the company started to supply high value-added industrial expansion joints to export markets after acquiring International Accreditation - ASME U-Stamp. Further to ISO9001 and QS9000, SJM earned ISO 14001 in 2002 and TS16949 in 2004.

The success in the expansion of the automotive business with innovative solutions made SJM become a market leader in this product segment. SJM is therefore a reliable partner in the development and manufacturing of decoupling solutions in passenger cars as well as in light and heavy commercial vehicles for all major vehicle manufacturers in Asia, Europe, North and South America. Two new plants in China, opened in 2009 in Yantai and in 2012 in Changsha, and also a new plant in Mexico, opened in 2016, follow the international trend in the automotive industry to be present in the vicinity of its customers.

SJM continues - step by step - to utilize and expand this global network even more actively now and in the future to fulfil our role as a professional technology driven company through anticipation of new and diverse market opportunities, with projected expansion into industries such as semi-conductors, medical instrumentation, aircraft, and telecommunications.