自動車部品製造における自然素材の不確実性とサプライチェーン

―高知県自動車部品企業の事例考察から―

抄録

This paper identifies problems unique to natural materials supply in the automobile parts manufacturing sector. It investigates methods and solutions through a case study of a car parts supplier that manufactures steering wheels from bamboo. Parts suppliers that use natural materials to manufacture automobile parts are hampered by supply instability due to uncertain material procurement and fluctuating demand from automakers. This study found that these issues can be solved by inventory control implemented by parts suppliers. The adjustment leads to expansion of inventory. Therefore, the supply chain of natural materials should be designed on the premise of holding a considerable amount of inventory.

In supply chain design, it is usual to avoid stockpiling large inventories in order to minimize costs. However, this case study shows that reducing inventory is not always the best strategy. This paper suggests that parts suppliers could play a key role in overcoming problems peculiar to supply chains of natural materials. Parts suppliers can coordinate downstream sales information with upstream material supply information, adjust the buffer inventory, and modify the difference. Communication of downstream information to and cooperation with upstream material suppliers will be essential to the stable procurement of natural materials.