This paper systematically reviews the impact of non-planar slicing strategies on the mechanical performance of fused filament fabrication (FFF) components. While prior studies have explored geometric and surface quality improvements, a consolidated understanding of mechanical performance enhancement remains limited. This review aims to quantify these improvements and identify the governing factors influencing performance outcomes.
A systematic literature review was conducted following PRISMA guidelines, analysing 24 peer-reviewed studies published between 2012 and 2025. A total of 794 samples and 233 experimental data sets were examined. A standardized “Improvement (%)” metric was adopted to enable cross-study comparison of mechanical performance, despite variations in materials, geometries and process parameters.
The results indicate an average mechanical performance improvement of 49.2% when using non-planar slicing compared to conventional planar approaches, although 17.2% of cases reported performance reductions. The effectiveness of non-planar slicing is strongly influenced by toolpath alignment with stress fields, high count of degrees of freedom in motion systems and usage of composite materials. Advanced implementations, including multi-axis and robotic systems, demonstrate the highest performance gains but introduce increased process complexity.
To the best of the authors’ knowledge, this is the first systematic review to aggregate and mathematically standardize the mechanical performance gains of non-planar FFF across disparate data sets. By introducing a unified comparison metric and identifying key performance drivers and limitations, this study offers both theoretical insight and practical guidance for process optimization and future research in additive manufacturing.
