Ergonomic Assessment in Designing a Semi-Automatic Silk Screen Printing Machine A RULA Analysis for Reducing Repetitive Strain in SMEs

Abstract

The silk screen printing process remains widely used due to its versatility and ability to deliver high-quality prints. However, the conventional manual approach is characterized by repetitive strain, inconsistent print quality, and slow production. This study focuses on the design and development of a semi-automatic silk screen printing machine to address these challenges while emphasizing ergonomic improvements. Field testing compared manual and semi-automatic methods in terms of production time, print consistency, and ergonomic outcomes, assessed using the Rapid Upper Limb Assessment (RULA). Results show that the machine reduced printing time per shirt from 25 seconds to 12 seconds, and steps required decreased from 10 to 6. Ergonomic assessment confirmed reduced strain and musculoskeletal risks for operators. Although the 24V stepper motor caused slower squeegee movement and minor ink blockage, the overall performance demonstrated significant improvements in productivity, ergonomic safety, and consistency. The semi-automatic machine provides an effective solution for small and medium enterprises (SMEs), offering a foundation for further optimization in ergonomic industrial design.