Solution Case 01 Reduce Burdens on Shipyard Workers
S-FREE™ Welding Cables Using a High-Strength Aluminum Conductor
Light, durable and heat resistant welding cables
Kure City in Hiroshima Prefecture, where there is a shipyard of Japan Marine United Corporation (hereinafter, JMU), has long been known as a city of shipbuilding. JMU is a leading shipbuilding company established in 2013 by a merger between two Japanese major shipbuilding companies——Universal Shipbuilding Corporation and IHI Marine United Inc. With a wealth of experience and advanced technologies, the company builds a broad range of ships centered on container ships, as well as tankers, naval ships, and passenger and car ferries. A ship body consists of steel plates joined by welding. Therefore, welding assumes the role of ensuring the quality of ship bodies and accounts for a large proportion of man-hours, being considered one of the most important processes in shipbuilding. S-FREE™ welding cables using a high-strength aluminum conductor have been adopted as traveling cables to supply power to welding equipment. We interviewed Mr. Masayuki Kikkawa of the Shipbuilding Department, Kure Shipyard, JMU about the process until the adoption.
“We have been using welding cables of various manufacturers. However, as the replacement of aged cables and the procurement of new cables proceeded, there was a growing opinion that we should narrow them down to a single manufacturer to avoid differences in product properties by manufacturers. Until then, the Kure Shipyard had not done any business with the Sumitomo Electric Group; however, the cables we used as a trial were easy to use due to their characteristic sheaths. Then, around 2014, welding cables using a high-strength aluminum conductor were proposed as new products,” says Mr. Kikkawa.
Before then, light welding cables using an aluminum conductor had been proposed by multiple manufacturers. However, in the end they were not adopted due to their insufficient durability. Lightness was not the only reason for the acceptance of the welding cables using a high-strength aluminum conductor supplied by the Sumitomo Electric Group. To verify whether the products have the same level of properties, such as durability, corrosion resistance, heat resistance and drag resistance, as conventional cables using copper (annealed copper), various tests were conducted for a year under conditions assumed to occur in actual use. As a result, the “lightness” and “equivalence to conventional cables using copper” of the products were verified, which led to JMU’s decision to adopt the products. Compared to conventional products, the properties of the products are as follows: the cable weight is lighter by 50% or more; the heatproof temperature is improved from 60°C to 90°C; and the wear of the sheath is less by 60% or more.
Workers’ voice of joy—“It’s so light!”
The full-scale introduction of the products started in August 2016. What changes have the products produced at welding sites? Mr. Takuya Kusaba, a colleague of Mr. Kikkawa in the Shipbuilding Department and a team leader, says that the introduction of the products has considerably changed the work environment.
“Site workers say that the products are so light that they are much easier to carry. Welding involves hard work such as walking up and down stairs with heavy cables. Not a few welding workers are middle-aged or older. We are now promoting the introduction of aluminum cables as standard cables for the welding machines we purchase; however, we have so many welding machines that we have not finished replacing. We often receive inquiries from site workers asking when aluminum cables will be introduced, which proves that the products are highly regarded. In addition, light welding cables help us develop a work environment that encourages women to work at sites,” says Mr. Kusaba.
In the future, what features will be required for welding cables? Mr. Kusaba points to the characteristics of welding work unique to the shipbuilding industry.
“Unlike other industries in which the line production method can be used, in the shipbuilding industry, welding is performed differently for each ship, and therefore manpower is indispensable. To further reduce burdens on workers and improve work efficiency, I expect the Sumitomo Electric Group to further develop thinner and lighter welding cables,” says Mr. Kusaba.
The aforementioned Mr. Kikkawa also expects a lot from the Sumitomo Electric Group.
“We are now proactively introducing welding cables supplied by the Sumitomo Electric Group. In this process, we requested the Group to develop welding cables with further advanced features, such as cables with colored sheaths for identification purposes and a wider variety of cable sizes. As a partner to improve our work sites together, I expect the Group to develop welding cables that make it possible to further improve work efficiency with innovative technologies and ideas,” says Mr. Kikkawa.
NEXT
Solution Case 02 Constituting Stable and Reliable Drainage Pump Systems —S-FREE™ Traveling Cables
（5）