Experience shapes fixation: How manufacturing background influences student and professional computer-aided design behaviour

Manufacturing Fixation in Design (MFD) – the unintentional bias towards certain manufacturing processes during design – has primarily been studied in the context of early-stage ideation. This study is the first to investigate the presence of MFD in the detailed design stage, specifically within Computer-Aided Design (CAD) modelling. We explore whether participants’ previous manufacturing experience alone predicts their modelling tendencies, distinguished by an additive or subtractive approach. We further compare how MFD manifests among novice students and experienced professional engineers. In an observational study with 30 CAD users, we employed a mixed-methods data analysis approach. Participants were quantitatively categorized on an additive–subtractive spectrum based on their CAD audit trail data, and this categorization was then validated through qualitative analysis of their verbalized thought processes and reported manufacturing backgrounds. Our findings reveal noticeable differences between additive and subtractive modelling approaches, reminiscent of distinctions in manufacturing processes such as 3D printing or machining. For most participants, their preferred manufacturing process aligned with the categorization derived from their CAD audit trails. Finally, we observed a generational difference: student participants predominantly favoured 3D printing and displayed additive MFD. Our first-of-its-kind examination of MFD in the detailed design stage, along with our reliable analytical framework for identification, has important implications for CAD education, industry onboarding, and design collaboration. By deepening our understanding of MFD in CAD, we highlight the critical need for improved integration between design and manufacturing to ensure an efficient and effective product development lifecycle.