Mass Customization of Polylactic Acid (PLA) Parts via a Hybrid Manufacturing Process

Abstract

Mass customization is the development of items tailored to specific customers, but produced at low unit cost in high-volume. In this context, hybrid manufacturing (HM) combines fused deposition modeling (FDM) and injection molding (IM) to fabricate a single personalized part with minimum manufacturing cost. In this technique, inserts with different physical features are first FDM-fabricated and then IM-overmolded. This study investigated the effect of hybrid FDM-IM production technology, FDM insert geometry on mechanical properties, and micro-structural evolution of Polylactic Acid (PLA) samples. The findings indicated a comparable tensile properties of FDM-IM samples (68.38 MPa) to IM batch (68.95 MPa), emphasizing the potential of HM in the manufacturing industry. Maximum tensile stress of FDM-IM specimens shows an upward trend due to the increased infill density of preforms. In addition, overmolding interface direction results in a big gap for the maximum tensile strengths between half-length series specimens (12.99 MPa to 19.09 MPa) and half-thickness series specimens (53.83 MPa to 59.92 MPa). Furthermore, four joint configurations resulted in different mechanical performances of finished specimens, in which the female cube sample exhibits the highest tensile stress (68.38 MPa), while the batch with male T joint shows a lower value in maximum tensile strength (59.51 MPa), exhibiting a similar tensile performance with the half-thickness 75% batch without joint configuration. This study lays the groundwork for using HM to produce bespoke and mechanically improved parts over FDM alone.