Thesis overview

My Ph.D. thesis, titled “Experimental Investigation on Surface Finishing of Metal Additive Manufactured Features Using Abrasive Flow Finishing (AFF)”, addresses one of the most critical challenges in metal additive manufacturing: the poor surface morphology of as-built components.

Metal AM processes such as Selective Laser Melting (SLM) and Atomic Diffusion Additive Manufacturing (ADAM) are capable of producing highly complex shapes. However, these processes inevitably generate significant surface defects, including: High surface roughness, Balling and partially fused particles, Staircase effect, Lack-of-fusion pits, Micro-cracks, Waviness and irregularities. These defects severely affect fatigue strength, tribological behaviour, dimensional accuracy, and functional performance in real-world applications.

Abrasive Flow Finishing (AFF), a mechanical-energy-based finishing process, is capable of reaching deep internal channels, curved surfaces, lattice structures, and freeform AM features where traditional finishing cannot reach. However, the commercial abrasive media used in AFF are expensive, proprietary, and lack tunability, making them unsuitable for widespread industrial use.

This thesis bridges that gap by developing a new polymer-based abrasive medium, analyzing its rheology, and applying it to multiple types of AM components. The research presents:

• Detailed understanding of AFF on different AM surfaces

• Mechanisms of material removal and defect elimination

• Optimization of finishing parameters

• Cost–performance analysis

• Surface integrity enhancement across various AM metals

This work provides a complete scientific and experimental framework for finishing additive-manufactured metal parts using AFF.