Tensile testing (Force vs mm Displacement) of ISO 527-1 PA-12 specimens.

Following an evaluation of the current scope of the AM industry, Selective Laser Sintering (SLS) was chosen as the most suitable process for this project, due to its reliability, precision and unparalleled design freedom. 

ISO 527-1 compliant tensile testing was carried out on the likely material candidates, and it was determined that PA-12 nylon met the mechanical performance specifications, whereas TPU-90A did not.

As the part was intended to replace a machined aluminium component, the material was required to maintain rigidity with minimal mass.

Final optimised mesh output from Fusion. 

Initial generative design atemps were abandoned in favour of topology optimisation, using the original bracket as a design space.

Load cases were applied based on the actual seating mechanism conditions, I tasked the algorithm to: 

• Retain critical mounting interface geometry

• Maximise stiffness

• Maintain safety factor

• Enforce X-axis symmetry for printability

This produced a promising mesh, which would need converting to a parametric model to allow for accurate modifications.

Detail of the most complex area of the parametricised model.

Due to the complexity of the mesh output, a manual parametric reconstruction was completed in Fusion, using complex lofts, pipes, and fillets. This allowed for a modifiable, simulation-ready model and ensured print compatibility.

It was challenging to keep accurate to the mesh output, but through careful work, < 2mm maximum deviation was achieved.

Fusion FEA output of both load cases with 5% exaggerated deformation.

Two FEA studies were performed using corrected, separate load cases.

• Load Case 1: Safety factor 2.267

• Load Case 2: Safety factor 2.473

A physical prototype was manufactured using PA-12 with 50% recycled powder. In lab testing, the part passed Load Case 2, but partially failed Load Case 1 due to a localised unsupported region not fully anticipated by the simulation.

Post-test analysis identified that adding a small brace (approx. 1g of material) to the failing region would correct the issue. Though time constraints prevented retesting, simulation confirmed this fix would restore performance. 

Ansys Granta was used in the final report to evaluate sustainability of the project. 

Final grade 78/100.