4DS Framework for sustainable production

A case study in Additive Manufacturing

Abstract

Improving sustainability in industrial production requires holistic integration of environmental, economic, social, and technical indicators into decision-making processes. Most sustainability frameworks in literature emphasize environmental performance, while underrepresenting technical feasibility and economic viability, which are critical for industrial implementation. This study introduces a structured four-dimensional sustainability framework (4DS) integrating technical, environmental, economic, and social dimensions to support informed decision-making in industrial contexts. The framework is applied to the mechanical recycling of Polyamide 12 (PA12) waste generated from automotive prototyping and its reuse as filament for Material Extrusion (MEX). Multiple recycling pathways are designed and compared, differing in logistical configuration and material composition. Recycled PA12 filaments produced from different flake/powder ratios are experimentally evaluated through tensile testing. Filaments produced from old PA12 powder without flakes generally exhibit more stable mechanical behaviour and improved printability compared to mixed flake/powder formulations, which show increased mechanical properties variability. The experimental results are integrated into a quantitative sustainability assessment and a multicriteria decision analysis to account for company-specific priorities. The findings demonstrate that the most suitable recycling pathway does not necessarily correspond to the lowest-cost or lowest-impact option when individual sustainability dimensions are considered. The results highlight the importance of balanced, context-specific sustainability assessment that integrates experimental material performance with environmental, economic, and social criteria to identify implementable industrial recycling solutions.