Sumitomo Wiring Systems × Local production for local consumption

Rather like the human body’s networks of blood vessels and nerves, wiring harnesses transmit power and signals throughout a vehicle. Wiring harnesses consisting of hundreds of wires are assembled by painstakingly placing connectors and electronic control units (ECUs) in accordance with drawings corresponding to vehicle models.

Automation of wiring harness manufacturing is difficult owing to its complexity, and even today, Sumitomo Wiring Systems employs many people to manufacture these products at its sites around the world. From the viewpoint of cost competitiveness, the company manufactured wiring harnesses for North America at plants in ASEAN countries, making long-distance transportation, along with the associated CO₂ emissions, unavoidable. Moreover, the recent global shortage of semiconductors and the impact of the COVID-19 pandemic have highlighted the drawbacks of the labor-intensive business model. This is the context in which Sumitomo Wiring Systems is establishing a system geared to local production for local consumption.

In order to realize local production for local consumption, Sumitomo Wiring Systems is pursuing initiatives to automate manufacturing processes previously considered unsuited to automation. Examples of such initiatives include application of the set operation, which is particularly advantageous in terms reducing man-hours, and the introduction of split wiring harnesses.

Even with the conventional labor-intensive operation, about 15% of the entire wiring harness manufacturing process is automated, but the practical application of the set operation whereby cutting and crimping of wires are executed automatically, has led to a significant reduction in lead time. By integrating e-STEALTH W/H^® with an automatic assembly process for split harnesses, whereby each harness is divided into four or five modules, the company is aiming to achieve high-variety production with smaller part counts. The automation rate has been increased to about 50% on a model line. The higher the automation rate, the more feasible manufacture of wiring harnesses in regions with high manufacturing costs to promote local production for local consumption becomes, with the additional benefit of eliminating the CO₂ emissions associated with long-distance transportation.

Sumitomo Wiring Systems has also developed aluminum wiring harnesses that enable a reduction of around 12% in vehicle weight compared with conventional products. Lightweight wiring harnesses from the manufacturer with the leading global market share are expected to make a substantial contribution to the reduction of CO₂ emissions from vehicles on the move.

Although there tend to be trade-offs between tackling social issues and attaining strictly commercial objectives, Sumitomo Wiring Systems will seek to resolve such issues while, at the same time, achieving business growth.