Enhanced Build Plate Design for Vat Photopolymerization Additive Manufacturing

Vat photopolymerization additive manufacturing (VPP) is characterised by high level of customisation, wide range of available materials and high resolution allowing for production of parts on sub-millimetre scale. It became the de-facto
production standard for custom-fit hearing aids, a growing tool for dental crowns fabrication and found its potential in many other applications such as robotics, functional surfaces and soft tooling [1, 2]. The increased market demand
together with the miniaturisation of complex structures manufactured by VPP calls for increased control over the fabrication process. For this purpose, all the elements of the process chain, from design to application, need to be optimised. The fabrication step is critical as it involves essential elements, such as process parameters and the performance of the VPP system hardware. One of these aspects concerns the attachment of the part to the build plate. Typically, an increased UV light exposure time or irradiance is used for the fabrication of the bottom layers to provide enhanced adhesion between the cured photopolymer and the build plate [3]. The sufficient level of the UV dose however depends on the applied resin and build plate material and it is determined experimentally. Selection of the suitable parameters is a difficult task, as insufficient light will lead to a lack of attachment, whereas high level of curing will create excessive adhesion and eventual damage to the part during removal. Furthermore, due to the high UV dose, the initial layers often undergo overcuring. Such a phenomenon causes distortions in the part leading to deteriorated functionality. This work undertakes the study on an approach toward more efficient build plate structure to optimise the balance between the sufficient adhesion of the photopolymer-based component and the ease of its removal during the post-processing phase.