How to reduce the weight of an aircraft structural element by one third

The S-shaped bracket is an element of the executive mechanism of the aircraft’s lift increase system.

ASCO Industries and SLM Solutions have once again proved the effectiveness of selective laser melting technology for the optimization and additive production of an aircraft structural element . The new solution allowed us to improve the design and reduce the mass of the part, as well as reduce the overall assembly and machining time.

About ASCO Industries nv

ASCO is a Belgian aerospace company headquartered in Brussels. It is a recognized world leader in the development of mechanisms for driving slats (on the leading edge of the wing) and flaps (on the trailing edge of the wing), as well as machining high-strength steels, titanium and aluminum alloys . ASCO is also renowned for its wide range of manufacturing and assembly capabilities for creating high-precision and cost-effective solutions for aircraft chassis and structural components such as fuselage frames and engine mounts.

Structural element of the Kruger shield drive mechanism

The considered S-shaped bracket is a structural element of the Krueger flap drive mechanism developed by ASCO as part of the AFLoNext project. It is believed that the Kruger shields are able to effectively replace the slats on the leading edge of the wings in future platforms with a laminar flow around the wing.

The bracket serves as a hinge connecting the Kruger shield to a fixed leading edge. Its elegant shape is the result of stringent requirements for the distribution of space and high loads on the seating surface. The initial design involved machining the bracket by ASCO. The machined version is made of high-strength stainless steel and weighs 2005. Interest in this element is due to the fact that in its original form it requires complex machining and has a poor material utilization rate.

Solution Found: Selective Laser Melting

ASCO and SLM Solutions have implemented a joint optimization project to get the best new S-bracket design. SLM Solutions engineers participated in the evaluation of the various design stages in order to increase manufacturability. The use of SLM technology (installation with two lasers) allowed to reduce the manufacturing time from 82 to 48 hours. SLM Solutions was able to successfully set up the process taking into account the operational stresses of the structure and the heat transfer properties of large titanium parts.

Bracket design optimization

Since printing an element designed for machining provides few additional advantages, the design of the S-shaped bracket was redesigned for additive production by topological optimization . Its goal was to minimize weight while maintaining the necessary strength to withstand aerodynamic loads specified in the AFLoNext project. In addition, two other elements were integrated into the bracket. The mass of the bracket after optimization is 1416 g (the original unit weighed 2050 g), which means a 31% reduction in weight and a reduction in the total assembly time.

Increase material utilization

The utilization rate of the material of the machined version was approximately 17, and for a part printed on an additive installation SLM Solutions, this figure decreased to 1.5 (taking into account removable supports and a small amount of additional material removed during post-processing of surfaces with high accuracy requirements )

Reduction of machining time

The previous machining time, starting from the initial workpiece, was about 4.5 hours. Using selective laser melting technology, only a few surfaces need to be processed, which are highlighted in red in the figure at the top right.

The result of the 3D metal printing project

• 31% weight reduction and overall assembly time reduction.
• Combining three parts into one.
• The decrease in the utilization of the material from 17 to 1.5.
• Significant reduction in machining time.
• Reduce production time by 42% to 24 hours / part by using the SLM 280 Twin printer (compared to a single-laser printer).