Because every gram weighs in
Turkish Aerospace is determined to significantly reduce the weight of structural components as part of the development of the TÜRKSAT 6A geostationary satellite. One of these structural elements is the so-called “Star Tracker“ bracket, which carries an optical measuring device that continuously records the satellite's position in relation to the constellation of stars and calculates its exact position in orbit.
The main components of the star tracker bracket were previously milled conventionally and then bolted together. In total, the bracket consisted of 360 individual parts and weighed 4 kg.
Turkish Aerospace's goal was to use additive manufacturing to get a bracket that:
The solution was in the design
The feasibility check performed at project start revealed that the original design of the star tracker mount could not reasonably be manufactured with AM. Topology optimization did not lead to a satisfactory result either, with regard to the goals. So we conceived a completely new design for the bracket as part of an ADM-E project.
To do this, the corresponding forces and frequencies were analyzed that the bracket was not allowed to exceed or fall below. On this basis, FIT experts used CAD software (Fusion and Inventor) to develop a design that featured a thin-walled, hollow shell geometry with internal bracing. This design was optimized by means of simulation and iteration (Optistract) so that it withstood the various load cases with high acceleration forces without falling below the defined natural frequencies.
The major advantage of this design was not only the high stability of the bracket combined with its low weight, but also its simplicity, as it can be manufactured in one piece.
Qualified single-part manufacturing (ADM-Q)
Laser melting (PBF-LB/M) was used for the additive manufacturing of the star tracker bracket made of aluminum (AlSi10Mg). The 3D model was aligned at the optimum angle in the build space of the machine under cost and quality aspects and oriented with the required support structures to prevent distortion. The construction process, which took several days, was continuously monitored. Appropriate tensile specimens and density cubes were built to assess component quality. After support removal, the bracket was blasted to homogenize the surface. Finally, the connecting surfaces to the satellite and the optical unit were CNC-milled to ensure the required precision.
Quality tests passed
To prove component quality, the star tracker mount underwent various measurement and testing procedures in our quality labs, in particular, a micro ct scan after blasting and a 3D optical scan after CNC milling. In addition, other quality tests relevant to production, such as the measurement and control of tensile specimens and density cubes, were carried out so that the product could be delivered with the complete process and quality assurance documentation. Traceability requirements were also fully met. At Turkish Aerospace, the satellite bracket also successfully passed the test stations and is hence qualified as a fully developed space component for flight.
The special process requirements
The special challenge in the project was to develop a geometry that is both lightweight and extremely stable. The newly developed design and additive manufacturing of the bracket made this possible. Turkish Aerospace benefited from the following results:
Turkish Aerospace was won over by FIT's combination of industry understanding, design, and manufacturing expertise, as well as extensive in-house quality assurance capabilities. You too can benefit from our range of services.
|Scope of services:||Design development and simulation
Additive manufacturing and post-processing
Full process documentation
QA documentation (material test certificates, material certificates, measurement reports)
Packaging and shipping
|Delivery time:||30 working days (after data release)|
|Part dimensions:||760 x 200 x 200 mm|
|Part weight:||1.96 kg|
|Material:||Aluminum alloy (AlSi10Mg)|
|Technology:||Laser melting (PBF-LB/M)|
|Quality control:||Micro ct scan after blasting
Optical 3D scan after CNC milling