With a few exceptions, the modern stainless-steel propeller is created using the investment casting process, a metallurgical art that dates back more than 4,000 years. Also known as the lost wax process, ancient cultures used investment casting to create artwork and jewelry, usually carving a pattern from beeswax and investing, or covering, the wax pattern with a shell of clay. Molten copper, bronze or gold was then poured through a wax channel into the shell, displacing the wax. Once cooled, they knocked the shell away to reveal a replica of the original wax pattern.
This same process, though influenced by modern technology, is used to create marine stainless-steel propellers. We recently toured the Yamaha Precision Propeller Industries facility in Greenfield, Indiana, one of the newest investment casting foundries in North America. The 55,000-square-foot plant began operation in March 2021, and today all Yamaha stainless-steel props are cast here, then finished at a YPPI facility in nearby Indianapolis.
Yamaha, like any modern manufacturer, sought to utilize automation to improve quality, accelerate production, and enhance worker comfort and safety when it designed the Greenfield facility. The rate of production has certainly increased from 60,000 props per year before the Greenfield facility opened to more than 100,000 pieces currently, according to Yamaha. Automation also results in tighter manufacturing tolerances, reducing the amount of finish work each prop requires and produces repeatable performance on the water.
[https://cdn.magzter.com/1498743624/1677480720/articles/sUa3-ZESW1679896784669/0670175689.jpg]
The in-plant automation focuses primarily on the most popular Yamaha propeller lines, including the Saltwater Series II and Reliance, and on two aspects of the process: the coating of the wax pattern with refractory material, and the actual pouring of the molten stainless-steel alloy.
For these high-volume props, the wax pattern is formed in one piece within a steel die. Five patterns are then placed on a fixture and transported by conveyor to a set of robotic cells for the application of refractory material. The first prime coating, which will contact the stainless steel, is fine zircon sand, which creates a smooth finish. A robotic arm first dips the five patterns in a zircon slurry and then places them in a cabinet containing the rotating drum sprinkling zircon sand that clings to the slurry. Next, the robotic arm places each rack on a conveyor carrying them into an adjacent drying room, maintained at 72 degrees F and low humidity. A series of robotic cells coat each pattern five times. Subsequent coatings are coarser silica sand. The entire process takes about 24 hours. When complete, the refractory material looks like a coating of white stucco on the outside. Only three people are required to manage the entire dipping process. In the past, the patterns were hand-dipped in ...
This same process, though influenced by modern technology, is used to create marine stainless-steel propellers. We recently toured the Yamaha Precision Propeller Industries facility in Greenfield, Indiana, one of the newest investment casting foundries in North America. The 55,000-square-foot plant began operation in March 2021, and today all Yamaha stainless-steel props are cast here, then finished at a YPPI facility in nearby Indianapolis.
Yamaha, like any modern manufacturer, sought to utilize automation to improve quality, accelerate production, and enhance worker comfort and safety when it designed the Greenfield facility. The rate of production has certainly increased from 60,000 props per year before the Greenfield facility opened to more than 100,000 pieces currently, according to Yamaha. Automation also results in tighter manufacturing tolerances, reducing the amount of finish work each prop requires and produces repeatable performance on the water.
[https://cdn.magzter.com/1498743624/1677480720/articles/sUa3-ZESW1679896784669/0670175689.jpg]
The in-plant automation focuses primarily on the most popular Yamaha propeller lines, including the Saltwater Series II and Reliance, and on two aspects of the process: the coating of the wax pattern with refractory material, and the actual pouring of the molten stainless-steel alloy.
For these high-volume props, the wax pattern is formed in one piece within a steel die. Five patterns are then placed on a fixture and transported by conveyor to a set of robotic cells for the application of refractory material. The first prime coating, which will contact the stainless steel, is fine zircon sand, which creates a smooth finish. A robotic arm first dips the five patterns in a zircon slurry and then places them in a cabinet containing the rotating drum sprinkling zircon sand that clings to the slurry. Next, the robotic arm places each rack on a conveyor carrying them into an adjacent drying room, maintained at 72 degrees F and low humidity. A series of robotic cells coat each pattern five times. Subsequent coatings are coarser silica sand. The entire process takes about 24 hours. When complete, the refractory material looks like a coating of white stucco on the outside. Only three people are required to manage the entire dipping process. In the past, the patterns were hand-dipped in ...
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Boating (Digital) - 1 Issue, March 2023