Metal-based additive manufacturing in the aerospace industry
15 January 2019
Aircraft engine manufacturers are among the early users of metal-based additive manufacturing. Learn how ASCO achieves a weight reduction of 31% and the buy-to-fly ratio drops from 17 to 1.5 with laser-assisted component manufacturing.
ASCO Industries n.v.
ASCO is a Belgian aerospace company located in Brussels. It is recognized as a world leader in the development of mechanisms for the actuation of slats (Leading Edge) and flaps (Trailing Edge) and in the machining of high strength steels, titanium, and aluminum alloys. ASCO is also known for its extensive capabilities in manufacturing and assembly to create precision and cost-effective solutions for landing gears and structural components such as fuselage frames and engine attachments.
The challenge: AFLoNext Project
The work described in this Case Report and the research leading to these results has received funding from the European Community’s Seventh Framework Programme FP7/2007-2013, under grant agreement n°604013, AFLoNext project.
Structural component from a Krueger flap actuation mechanism
The Gooseneck Bracket is a structural component from a Krueger flap actuation mechanism designed by ASCO in the scope of AFLoNext. Krueger flaps are considered a viable alternative for slats on the aircraft leading edge, for future laminar wing platforms. The bracket functions as a hinge between the
Krueger flap and the fixed leading edge. Its elegant shape is the result of stringent space allocation requirements and high interface loads. The bracket was initially designed for machining by ASCO. The machined version is made of high strength corrosion resistant steel and weighs 2005 g. The interest in this component arises from the fact that the initial version is complicated to process and has a poor buy-to-fly ratio.
SLM SOLUTION: Joint optimization project
In the course of this optimization project, ASCO and SLM Solutions have chosen a collaborative approach to achieve the best design of the new Gooseneck Bracket. SLM application engineers were involved in the review of the different design steps to ensure manufacturability. The twin laser technology helped to reduce the build time from 82 hours down to 48 hours. SLM managed successfully to set-up a process that handled the stresses and heat transfer inherent with large titanium parts.
Redesign of the Gooseneck Bracket
Since there is little added-value to print a component that was designed for machining, the Gooseneck Bracket was re-designed for Additive Manufacturing using topology optimization. The target of the optimization was to minimize the weight while achieving the necessary strength to withstand the aerodynamic loads defined in the AFLoNext project. Moreover, two other components were integrated. The optimized weight is 1416 g (versus 2050 g for the assembly) which means a reduction in weight of 31% and a reduction of the total assembly time.
Improved by-to-fly ratio
The buy-to-fly ratio of the machined version is around 17 while in the case of the SLM version, the buy-to-fly ratio drops to 1.5 (accounting for the support structures to be removed and the small amount of extra material necessary for post-machining the interfaces with a close tolerance).
Reduced processing time
The machining time starting from a block was around 4.5 hours. In the case of the SLM version, it is only necessary to machine the few interfaces highlighted in red in the picture on the right.
Powder bed processes metal and ceramic (SLM, EBM, etc.)