Case Study: Titanium Satellite Bracket at 74 g Using DMLS Ti-6Al-4V — Topology Optimised

Industry: Space Technology  |  Process: DMLS Ti-6Al-4V  |  Volume: 12 flight articles  |  Lead time: 9 days

The Challenge

An Ahmedabad-based space-tech startup was developing a low-Earth-orbit (LEO) satellite for remote sensing. The payload mounting bracket — a structural interface between the satellite bus and the payload deck — had to survive 8G quasi-static launch loads in all axes with a safety factor of 1.5, while fitting within a 240×180×60 mm envelope. Mass was the overriding constraint: every gram added to the payload interface reduces the primary payload or increases launch cost.

The original design in 316L stainless steel, machined from solid billet, weighed 312 g. The programme director set a target of under 100 g without relaxing the load requirement. Layer X was brought in as the manufacturing and structural optimisation partner.

Topology Optimisation

The Layer X engineering team imported the solid 316L model into Altair Inspire. The boundary conditions applied: eight bolt-pattern attachment loads at the bus interface, one distributed load at the payload deck interface, representing the 8G worst-case launch condition. Preserve regions were defined around all bolt holes and interface surfaces — these must remain solid for assembly.

After four optimisation iterations, the resulting geometry carried the load through three primary load paths, each a thin-walled hollow section with internal ribbing. The infill was converted to a gradient lattice (5 mm cell, 0.4 mm strut) using nTopology, reducing mass while maintaining global stiffness.

The optimised titanium geometry was validated in FEA under the full 8G + 1.5 SF condition. Maximum von Mises stress: 542 MPa (Ti-6Al-4V yield: 910 MPa). Safety factor confirmed at 1.68 — exceeding requirement.

DMLS Manufacturing

Ti-6Al-4V powder (ASTM F2924, Layer X certified lot 24-TI-089) was used. Build was oriented to minimise support volume in the lattice interior. Post-build operations: stress relief at 840 °C, support removal, bead blast, and CNC post-machining of bolt hole diameters and interface datum faces to ±0.02 mm.

Twelve flight articles were produced in two builds. Each received: dimensional report against drawing, material certificate (mill cert + CoC), and HIP certificate (applied to all flight articles to close residual DMLS porosity and improve fatigue life).

Results

The brackets were qualified under vibration testing (GEVS-GEVS-7000 profile) and thermal cycling (−40 °C to +85 °C, 100 cycles) by the customer''s test team. All twelve articles passed without failure or non-conformance. The satellite is scheduled for launch in Q3 2026.