In this research, novel biocomposite filaments were developed by incorporating coffee silver skin (CSS) waste into polylactic acid (PLA) for use in Fused Filament Fabrication (FFF) technology. CSS was blended with PLA at concentrations of 0, 5, 10, and 15 wt.% to address the waste disposal challenge and produce environmentally friendly composite biofilaments for FFF, supporting circular economic efforts. These filaments have the potential to be used in sustainable prototyping, functional parts, and consumer products. A comprehensive analysis was conducted to examine the effect of printing temperature on dimensional accuracy, melt flow index (MFI), and mechanical properties. Higher printing temperatures and increased CSS content led to larger dimensions due to increased material fluidity, as confirmed by MFI results, which increased from 3.5 g/10 min (0% CSS) to 5.8 g/10 min (15% CSS) at 180 °C, reaching 26.3 g/10 min at 220 °C. Tensile tests on 3D-printed specimens indicated an improvement in elastic modulus with increasing CSS content at lower temperatures (180 °C), rising from 1622 MPa (0% CSS) to 1952 MPa (15% CSS), representing about a 20% increase. However, at higher temperatures, the elastic modulus decreased, possibly due to the poor dispersion and agglomeration of filler particles. Tensile strength generally decreased with CSS addition, especially at higher loadings, while yield elongation remained low (~1.4–1.7%), indicating a more brittle material. The findings also revealed no significant thermal changes with increasing CSS content, and good printability was achieved for all compositions, which was characterized by good layer adhesion, the absence of warping, and the ease of extrusion.

In recent years, Additive Manufacturing (AM) has transformed the development of new products, enabling more efficient, sustainable, and creative solutions across multiple sectors. Accordingly, this research explores the integration of Selective Laser Melting (SLM) with advanced Computer-Aided (CAx) tools, specifically Generative Design (GD) and Topology Optimisation (TO), to rethink an everyday product. The developed concept, an SLM water tap, highlights the seamless synergy between design and product engineering. Reverse Engineering (RE) was applied to analyse the conventional internal mechanism, which was redesigned in accordance with Design for Additive Manufacturing (DfAM) principles. This approach enabled the integration of the internal cartridge architecture into the tap body as a single metal component, reducing system complexity and part count. TO was applied to key components, achieving a 35% mass reduction without compromising the simulated structural performance of the system. GD was employed to generate optimised internal flow channels, resulting in a numerically simulated flow rate of 4.69 L/min. Integrating CAx tools enabled a customisable product with varied surface textures. This work contributes to the deconstruction of traditional manufacturing paradigms and advances the understanding of AM for functionally relevant product design.