The metal spinning machine, a propeller nozzle manufacturing method with basically one single weld only is now operational in the Chinese plant of Damen Marine Components (DMC). Consequently, the technique which DMC has revolutionized nozzle production is up and running at both of its plants.
“The nozzles can be manufactured somewhat lighter and have a smoother inside. Traditional propeller nozzle manufacturing requires a minimum ten up to thirty or more welds at the inside of the nozzle, depending on size. Our new technique requires less welding and in addition gives a much smoother surface,” said Cees Bons, Senior Production Manager with Damen Marine Components in China.
The novel spinning machine has just come on stream in DMC’s temporary plant Jiang Yin. The spinning machine of DMC in Gdansk, Poland has been performing superbly since early 2012. Meanwhile it has already delivered the proven technology status to this innovative manufacturing technique that ensures the shortest lead times in the industry.
The principle pivots around (literally) transforming a steel tube into a bell-shaped nozzle inner ring through mechanical cold molding. The technique most resembles the shaping of an open-ended vase on the potter’s wheel.
The spinning machine starts with a tube that has been plate rolled and welded – hence the one, single weld only - on the spot in DMC’s manufacturing halls. A calm and cautious process, it still far outspeeds the traditional patchwork-style welding of the nozzle inner ring from many steel parts, especially when the rings are big. The new spinning machine in China can go up to seven meters in diameter – starting from one meter. “We are able to make an extension on our spinning table up to a diameter of 10 meters,” Bons added.
“The machine in Jiang Yin, China can handle carbon steel to a maximum of 36 millimeters thickness, and stainless steel and Duplex to a maximum of 25 millimeters. Some clients want a stainless steel ring only in the nozzle’s central cavitation zone, with a carbon steel in- and outlet. This would still involve two welds only. It still is almost seamless,” noted Steef Staal, DMC’s Managing Director. He added that the traditional production method by means of the welding of multiple steel parts will continue to be used if the spinning machines in China or Poland cannot accommodate specific sizes or specials.
New China HQ
DMC’s new spinning machine was assembled in China by Korean engineers under the supervision of Cees Bons, assisted by some members of the Jiang Yin crew. It is a pioneer in more ways than one, being the marine components manufacturer’s first operation in Jiang Yin, near the Yangtze River.
A production hall is temporarily being rented there ahead of DMC’s removal, lock stock and barrel, from Suzhou. “As our 5,000-square-meter plant in Suzhou had become too small – also following our expanding manufacturing of winches – we have opted to move entirely,” Mr. Staal said. “Our new 12,000-square-meter complex is currently being built and by late 2014 we plan to have moved-in completely, including our show-piece propeller nozzle spinning machine.”