Surface finishing results by AFF
Surface finishing results by AFF
The Abrasive Flow Finishing (AFF) process developed in my Ph.D. work demonstrated significant improvements in surface quality across multiple metal additive manufacturing (AM) materials. The results show that a carefully engineered polymer–abrasive medium, combined with optimised AFF parameters, can deliver high-precision finishing even on complex geometries that are normally difficult to access.
AFF produced a highly uniform finish on ADAM copper surfaces, reducing roughness by up to 90%. The process effectively removed loosely fused metal particles, smoothed surface waviness, and improved overall dimensional uniformity. This demonstrated the medium’s capability to finish curved and intricate copper features with consistent results.
For laser-printed maraging steel, the developed medium achieved 93% reduction in areal surface roughness (Sa). Balling defects were eliminated within the early finishing cycles (~75 cycles), and melt-track ridges were progressively flattened. The finished surface showed significant improvements in texture uniformity, with optimized mechanical integrity suitable for aerospace-grade applications.
AFF successfully refined SLM stainless steel surfaces with excellent repeatability. Using statistical modeling (RSM and ANOVA), it was identified that number of cycles contributed the highest influence (~59.5%) towards surface improvement. The optimized process conditions produced smoother surfaces with minimal edge deformation and improved surface consistency.
One of the key outcomes of the research was demonstrating AFF’s capability to finish complex internal geometries such as spur gear teeth. The areal roughness (Sa) improved from 11.45 µm to 1.26 µm, showing near-mirror finishing inside tooth flanks. The medium’s creep behavior allowed it to penetrate deep into gear profiles, making this a highly effective post-processing solution for tooling applications.
Across all tested materials, AFF delivered:
Significant reduction in surface roughness (up to 90–93%)
Removal of AM-specific defects: balling, unfused particles, melt-track irregularities
Improved surface integrity and dimensional accuracy
High consistency across both simple and complex geometries
Applicability to internal channels, curved surfaces, and fine features
These results firmly establish Abrasive Flow Finishing as a powerful, adaptable, and economical post-processing method for modern metal additive manufacturing.