Experimental Assessment of Digital Work Instructions Supporting Assembly Procedures in the Mechanical Engineering Industry

Digitalization of assembly processes represents a key pillar of Industry 4.0 and human-centered manufacturing, particularly in environments characterized by manual operations and high variability. This study experimentally compares traditional paper-based work instructions with a digital workflow created using Vuforia Capture. The objective is to assess the impact of instruction format on assembly performance in terms of time efficiency, error rate, and the need for external assistance when assembling an unfamiliar mechanical mechanism. An experimental study was conducted with participants lacking prior experience with the given assembly task. Two conditions were evaluated: assembly guided by paper documentation and assembly supported by step-by-step digital instructions. The measured indicators included total assembly time, number and type of errors, and assistance interventions. The results indicate substantial improvements when using digital instructions. Average assembly time decreased from 1084.8 s to 599.4 s (−44.75%), the total number of errors was reduced from 56 to 9 (−83.93%), and the need for assistance decreased from 58% to 2% of assembly steps. These findings suggest that digital work instructions significantly enhance user guidance, reduce cognitive load, and improve process stability, particularly for inexperienced users. The results should be interpreted with caution due to the limited sample size and controlled experimental conditions. Nevertheless, the study provides practical implications for practitioners and managers in manufacturing, as well as insights for researchers investigating digital instruction systems and training support tools in industrial environments.