The Aerotecnic company and the Tekniker Technology Center collaborate in the LASTITAN project to optimize the manufacture of titanium components by means of Laser Metal Deposition with the contribution of powder
Current manufacturing processes, based mainly on subtractive manufacturing technologies (material removal processes) such as machining by chip removal, entail considerable losses of raw material, especially when it comes to geometries such as those found in titanium structural components for the aeronautical sector.
Furthermore, due to the fact that the alloys used in the manufacture of these parts are high-performance and high-cost materials, these material losses in the manufacturing process represent an extra cost for the manufacturer. Thus, additive manufacturing technologies represent a great opportunity for the most representative companies in this industry due to their high potential to minimize the amount of material required to manufacture any type of part or component.
The Tekniker Technology Center, a member of the Basque Research and Technology Alliance (BRTA), has collaborated with Aerotecnic, a manufacturer specialized in aeronautical parts, in the LASTITAN project, whose objective has been to study and optimize the use of the advanced manufacturing technique Laser Metal Deposition ( LMD), in its aspect of contribution of material in powder form, an innovative additive manufacturing technique, for the development of titanium parts from the Aerotecnic catalog.
In this way, the collaboration between both industrial players opens the possibility of replacing the traditional manufacturing process of different structural components, of the Ti6AI4V alloy, typical of the sector, with this novel technique, which consists of the deposition of successive layers of material in form of metallic powder injected onto the surface of a given substrate, by fusing it through a high-power laser beam.
With the results of LASTITAN, Tekniker seeks to position itself at the forefront of the aeronautical sector as a trusted expert in additive manufacturing techniques that represent a revolution for the aeronautical industry.
Pieces of different geometries
To do this, firstly, Tekniker and Aerotecnic have selected the two pieces to be manufactured within the framework of the project. The manufacturer preselected 12 components and the center then chose the two most representative ones, with different geometric aspects: a piece with sloping parallel walls and another with crossed walls. The second step of the project has consisted in the development of a Tekniker robotic cell, in which an inert atmosphere chamber has been installed to avoid the oxidation of the pieces during the construction process of the same.
“Titanium tends to oxidize easily at high temperatures, so an inert atmosphere chamber has been installed which, after filling it with argon, allows the supply process to be carried out in an atmosphere with less than 10 parts per million of oxygen”, explains Josu Leunda, researcher at the technology center.
Third, experimental tests have been carried out on flat specimens in order to obtain the appropriate parameter window for the laser supply process, as well as the most suitable supply strategies to manufacture the defined geometries.
Next, the optimization of the manufacturing process of the 3D geometries has been carried out, that is, the manufacture of prototypes with characteristic geometries of the final components, in reduced sizes to adjust the strategies to each final piece. These prototypes have served for Aerotecnic to carry out the pertinent tests in order to adapt the machining process to this new type of parts. Likewise, in this phase the contribution efficiency has been measured in order to be able to quantify the amount of material lost in the form of non-melted dust particles.
Finally, the selected demonstrators have been manufactured, measuring the total time of the manufacturing process for both demonstrators, and this data has been used to assess the process from both a technical and economic point of view, and thus be able to compare it with the process of current manufacturing.
A dimensional control of the demonstrators has also been carried out in order to verify that the deformation is less than the maximum admissible. Finally, they have been sent to Aerotecnic to be machined under finished conditions, until reaching the final dimensions.
The results obtained in the project will serve Tekniker and Aerotecnic to open new lines of research and collaboration in which they can address and delve into aspects such as the optimization of the machining process, the possibility of using heat treatments to improve the microstructure of the components and even the possibility of using filler material in the form of wire to improve the efficiency of the process and the finishing of the pieces.
