Influence of bed temperature on mechanical resistance, surface and dimensional quality of 3D printed parts by robotized fused pellet modeling

Additive manufacturing has become a common practice across various industries due to its ability to efficiently produce complex parts on low and medium scale. Among the various adopted techniques, the fused pellet modeling (FPM) technique stands out, utilizing polymer pellets as raw material. However, achieving functional parts with good surface quality and mechanical strength remains a challenge when using FPM. These issues become even more complex when dealing with larger parts, as the associated thermal gradients tend to be more pronounced. The present research project aims to investigate the effect of print bed temperature on the mechanical strength, surface quality, and dimensional accuracy of parts printed using the FPM technique with ABS polymer pellets. An actively controlled heated bed was developed and integrated into a manufacturing cell dedicated to 3D printing of large-scale products, with volumes of up to 1 m³. This manufacturing cell features a single-screw extruder manipulated by a six-axis industrial robotic arm. The primary goal is to assess how precise control of print bed thermal conditions can impact the mechanical strength and quality of produced parts. This study addresses the influence of thermal gradients on additive manufacturing of ABS parts. Mechanical properties showed no significant correlations with temperature analyses at various levels. However, results from dimensional analysis and surface quality highlighted the critical importance of precise print bed temperature control, affecting parts according to different levels. Application of methods like dimensional analysis and microscopy revealed significant result variations. Furthermore, results across different print bed temperature levels proved crucial to part quality. These findings contribute to a comprehensive understanding of the intricate interplay between temperature, print parameters, and properties of parts manufactured using FPM, offering valuable insights for future process optimizations.