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No abstract

Injection molding using inserts from vat polymerization, an additive manufacturing technology, has been investigated for pilot production and rapid prototyping purposes throughout the past years. A standard mold is equipped with additively manufactured inserts in a rectangular shape of (20 x 20 x 2.7) mm 3 and (60 x 80 x 10) mm 3 produced with vat photo polymerization. This contribution discusses the heat transportation within the inserts made from a thermoset material, brass, steel, and ceramic material. It therefore elaborates on the possibilities of injection molding as well as the thermal challenges connected with the use of polymer inserts. They are an essential part for further calibrations of the injection molding process, which suffers from reduced lifetime due to the poor thermal conductivity of polymer inserts as compared to metal inserts. Multiscale inserts combining micro features at larger inserts in the cm-range.

Additive manufacturing technologies applied to injection molding process chain have acquired an increasingly important role in the context of tool inserts production, especially by vat polymerization. Despite the decreased lifetime during their use in the injection molding process, the inserts come with improvements in terms of production time, costs, flexibility, as well as potentially improved environmental performance as compared to conventional materials in a life cycle perspective. This contribution supports the development of additively manufactured injection molding inserts with the use of fiber-reinforced vat polymerization technology. The life cycle assessment of the prototyping process chain for rapid prototyping with high flexibility provides a base for industrial applications in injection molding.

Additive manufacturing vat polymerization has become a leading technology and gained a massive amount of attention in industrial applications such as injection molding inserts. By the use of the thermoset polymerization process inserts have increased their market share. For most industrial applications, strength and stiffness are crucial factors to a successful implementation of cured photopolymer thermosets. Hence, fiber-reinforced polymers have recently been introduced. The behavior and especially orientation of fibers during the vat photopolymerization process has yet not been fully understood. Research indicates an orientation within the manufacturing layer and efforts have been made to achieve a more uniform orientation within the part. A vat polymerization machine consisting of a resin vat and a moving build plate has been simulated using the fluid flow module of Comsol Multiphysics™. A moving mesh with hyper-elastic behavior was utilized to simulate the flow of the photopolymer during the lifting of the build plate after a successful curing of a single layer. The velocity profile can thereafter be used to estimate a prediction for the orientation of the short fibers added to the liquid photopolymer resin. The prediction can be used to identify potential clusters or misalignment of fibers and in the future allow for optimization of the machine design and manufacturing process.