Analysis of 3D Printed, Wooden and Thermocoal Patterns for Sand Casting: A Comparative Study

Sand casting remains a fundamental manufacturing process for producing metal components with complex geometries. The characteristics of the pattern significantly influence the quality, dimensional integrity, and surface finish of cast products. This study presents a comparative experimental evaluation of sand-cast components produced using 3D printed, wooden, and thermocoal (expanded polystyrene) patterns. The comparison is conducted based on cost, surface roughness, dimensional accuracy, production time, and durability. The study establishes that no single pattern material is universally superior; rather, the optimal choice depends on the specific production context. While the wooden patterns remain the industry standard for high-volume production where surface finish and tool longevity are paramount, they suffer from high initial lead times and labor costs. Conversely, 3D printed patterns demonstrate significant advantages in rapid prototyping and complex geometries with good dimensional accuracy, reducing tooling lead time compared to traditional methods. Thermocoal patterns provide a low-cost alternative for specific applications but are limited by lower dimensional stability, surface integrity and low-volume production. The study offers practical insights into pattern selection and concludes with a decision matrix to guide foundry engineers in selecting the optimal pattern material based on production volume, part complexity, and budget constraints. The findings suggest that hybrid approaches, such as combining 3D printing with surface finishing techniques, can enhance performance and broaden industrial applicability.