Through the use of innovative production and process techniques the investment casting specialist TITAL was able to develop in cooperation with renowned project partners a new and very complex titanium investment casting component for the military carrier A400M. Besides TITAL the CASSIDIAN company located in Manching / Bavaria and Premium Aerotec located in Augsburg were part of the interdisciplinary project team. The component is a jacketed fuel pipe (T-Fitting) with extremely high system security. According to TITAL GmbH not only is this T-Fitting unique in Europe but also the applied laser welding process provided by Premium Aerotec. The extremely lightweight component could only be developed in close cooperation with many technical disciplines and specialists. The end customer is Europe's biggest aircraft company AIRBUS. All companies involved with this unique titanium component applied for the AIRTEC award which was given for the second time at the AIRTEC fair taking place in Frankfurt from November 2 to 4.
The jury of the AIRTEC Award was very impressed with the technical complexity of the T-Fitting. During the AIRTEC tradeshow it granted the Golden AIRTEC Award to TITAL GmbH, CASSIDIAN and Premium Aerotec. The prize was awarded on the 5th anniversary of the AIRTEC in gold, silver and bronze. The AIRTEC award recognizes exceptional achievements as well as technical and economical solutions.
The component with three tube outlets (dimensions 400 x 250 x 210 mm or 16 x 10 x 8 inches) is characterized by its extremely thin wall thickness and a weight of only 5 kilograms which makes it considerably lighter than conventionally produced components. This saves fuel and CO2 during flights and thus also saves the environment. "Our task was to design six titanium investment castings for one jacketed pipe which exhibits this low wall thickness of only 1.8 mm (0.1 inches) and very tight tolerances", explains Dirk Friedewald-Witte, Engineering Manager at TITAL GmbH.
Another particularity: The separate titanium investment castings had to be produced so precisely by TITAL GmbH and subsequently had to be mechanically treated at the joint patches that Premium Aerotec in Augsburg could joint them together using the laser welding technique. This welding process is another unique feature of this component. To date this new laser welding technique has not yet been applied to titanium components in the commercial aircraft industry. The normal welding processes for titanium using the WIG technique are very labor intensive.
Due to a very high level of automation the Premium Aerotec laser welding process represents a forceless and very reproducible production process with a low impact on the alloy. "Due to a relatively low heat input we were able to develop a production strategy which enables components that do not need any post-processing", says the engineer. Therefore the production is much leaner and more economic.
Almost three years passed from concept to full rate production. "From the idea to the first draft we have worked very intensively on a design suitable for construction", reports Dirk Friedewald-Witte. First different manufacturing concepts and production alternatives had to be evaluated in order to produce the required characteristics of the component. Now the finished T-Fitting has eight joints. In order to achieve the required weld-seam geometries the joint patches were equipped with centralizing overlaps. The goal was to use one laser welding head for all joints. "That was not easy", sums up Friedewald-Witte. Considering the different specifications and the required inert gas cover, this task turned out to be rather difficult. By using optimized nozzle geometries all weld-seams could be produced in a reliable and discoloration-free manner.
Currently the component as well as the new production process is being tested by AIRBUS. As Dirk Friedewald-Witte says now they only have to wait for the T-Fitting to pass the strict quality requirements of AIRBUS. "We expect the results in 2011", says the Engineering Manager.
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