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Nakashima Propeller is a general manufacturer of marine propellers and other propulsion equipment. Nakashima Propeller provides reliable propulsion equipment for vessels navigating the world’s oceans and seas.
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World-class propeller factory
Nakashima manufactures propellers by maximizing its assets in all production processes including casting, processing, and finishing processes. By combining “craftsman skills” with “digital technology” Nakashima’s unique expertise is integrated in order to reproduce complex shapes of propellers that handle fluids by converting two-dimensional design data into three-dimensional solid.
Advanced technology: Digital technology
Reproducing a propeller shape that is as close to the original design as possible is the most important factor when manufacturing hydrodynamic propellers.
Nakashima efficiently co-develops equipment for manufacturing high-accuracy products together with machine manufacturers through shared discussion based on its many years of experience in the production of propellers, then introduces the equipment into its production line. Nakashima is continuing to make efforts to create “optimum manufacturing technology.”
Craftsman skills: Human skills
Craftsman skills are essential for built-to-order production and are irreplaceable, even by advanced machine processing technology. The craftsman skills of experienced workers are applied to the casting of the delicate curved surface of propellers.
Generally, when manufacturing casted products, first a model is created, then a casting mold is created based on the model. Propellers, however, are manufactured using a unique mold production method that does not use a model because each propeller must be built to order with the shape most suited to the purpose.
The original casting mold is created by a method known as the “rotating mold” method. The main points are positioned while directly measuring the casting mold using NC data displaying the displacement (angle, height) from the reference point. Next, experienced operators fill in the spaces between the points with sand to create a smooth surface for completion of an accurate casting mold surface.
Nakashima’s firm stance in the “pursuit of the optimum shape for each product” begins at this stage of producing the casting mold, which is the first step in the manufacturing processes.
Craftsman skills performed with highly specialized expertise and sensitivity are also used in the surface polishing process, where errors down to 1/100 of a millimeter are immediately found on the surface of propeller blades, and in the process to mate the propeller and shaft.
* The 1/100-mm error described in this section refers to outstanding relative error occurring on a continuous curved surface, instead of absolute error relative to the design value.
