Full speed ahead with cutting inserts from CERATIZIT!
Customer story: The Swedish shipbuilding company Aerodyn increases depth of cut by 50 %, thus doubling tool life
CERATIZIT S. A., Mamer, Luxembourg (headquarters), March 2008.
The Swedish company Aerodyn specialises in the machining of blades for propelling screws. The cast skin is eliminated and the profile finished through milling. After milling the surfaces are carefully polished. In this way, since the year 2000, several projects have been realized in close cooperation with the carbide expert CERATIZIT and productivity increased.
Propelling screw in application
The propelling screw converts the energy produced by the motor into motion. The propeller blades are characterised by a hydrodynamic wing profile. The blades are designed in such a way that the water streams around them asymmetrically when they rotate. A difference of pressure is caused in or contrary to the direction of movement. A current called ‘thrust’ is generated and drives the vessel.
5-axis milling centres for propelling blades
Aerodyn was founded in 1989 and first produced components for the aerospace industry: this is where the company name comes from. The company is based in the Swedish Karlskoga and has 40 employees who now specialise in the machining of propelling screws. In this special field Aerodyn is one step ahead. The secret: Aerodyn was one of the first companies to utilize 5-axis machining centres for the machining of this kind of blade. Previously, they used to be ground, not milled.
Per year the Aerodyn employees machine between 500 and 700 blades and numerous other components for propulsion systems of super oil tankers, freight vessels and cruise liners. The blades, cast in bronze or stainless steel, weigh between 80 kilos and 5 tons and are shipped directly to the company which equips the vessels with them. There they are assembled as propelling screws. The cycle time of one blade at Aerodyn ranges from two to three weeks or three months, depending on its complexity and size. The propelling screw has two to seven blades. Propelling screws for ice-breaking vessels are normally made of stainless steel. 75 % of Aerodyn’s blades are made of bronze, the others of stainless steel.
Maximum quality requirements – surface quality is decisive
Aerodyn’s quality requirements are extremely high. The customers’ specifications concerning both strength and form are very precise, in fact a surface roughness of Ra 1,6 is often demanded. Furthermore the weight of the single propeller blades should not differ from each other. With a given weight of the blades of 3.8. tons the tolerance is only 6 kilos, in a very fast vessel the difference in weight must not exceed one kilo. For every order independent audits are carried out before the products are released.
Productivity increase with CERATIZIT tools
In recent years several projects in the field of cutting tools have been realized in close cooperation between the Swedish Aerodyn sales and the CERATIZIT Energy & Transport segment. The CERATIZIT inserts -M31 CTC 5235 with HyperCoat-coating have, for instance, been applied now for several months. And the results are stunning. “Applying the CTC5235 inserts we have been able to increase the cutting depth by 50% and simultaneously double tool life. I don’t think we need to go into more detail here“, says a satisfied Petri Piippo, production manager at Aerodyn.
Lars Andersson, Aerodyn managing director, on the question about the particular advantages of working together with CERATIZIT states: “Quality, service and market-adapted prices are the characteristics of CERATIZIT. We also appreciate the possibility to be able to order online via the E-TechStore at CERATIZIT.”
The carbide expert CERATIZIT is synonymous with “hard material matters”
CERATIZIT S. A. – the company resulting from the merger between CERAMETAL and Plansee Tizit in 2002 – is a pioneer and global player in sophisticated hard material solutions. The company operates from Mamer, Luxembourg. In selected industrial sectors the 50% subsidiary of the Plansee group is the world market leader in unique and consistently innovative hard material products for wear protection and cutting tools. In the automotive industry, mechanical engineering, oil industry, medical systems, electronics as well as mould and die making customers benefit from this fact. 400 active patents are owned by CERATIZIT worldwide. In the year 2007 the company had a sales volume of 600 mill. euros and more than 4,000 employees.
The propeller blades are characterised by a hydrodynamic wing profile: blades weigh between 80 kilo and five tons. Propelling screws for ice-breaking vessels are normally made of stainless steel.
An Aerodyn employee is dwarfed by the large recently milled blade for a vessel propeller.
Laser-aided: an Aerodyn employee measures the cast blade, and determines the milling procedure.
Thanks to the CERATIZIT CTC5235 inserts with HyperCoat coating, Aerodyn was able to increase the depth of cut by 50 % and also to double the tool life.
From the left: Hans Axelsson (CERATIZIT sales manager Lars Andersson (Aerodyn managing director), Petri Piippo and Chung To (both of them Aerodyn employees) find the increase in productivity gratifying which they have achieved together.
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