Resumen: To address mass customisation demand trends, assembly line flexibility and productivity are critical. Industry 4.0 technologies could support assembly operations to this end. However, clear implementation methodologies are still lacking. This article presents two models for evaluating the most relevant Key Performance Indicators (KPIs) of manual or semi-automatic assembly lines, allowing to maximise the return of investment of any digital technology addition. MATLAB® was used to implement a parametric model, and FlexSim® was employed to build a discrete event simulation model. The models were validated using data of two industrial study cases from a global white goods manufacturer. Idioma: Inglés DOI: 10.1016/j.procir.2022.05.175 Año: 2022 Publicado en: Procedia CIRP 107 (2022), 1461-1466 ISSN: 2212-8271 Factor impacto SCIMAGO: 0.583 - Industrial and Manufacturing Engineering - Control and Systems Engineering