Abstract

With the rise of additive manufacturing (AM) technologies, a numerous limitations in conventional manufacturing have been circumvented. Additive manufacturing uses layer-by-layer fabrication of three-dimensional physical models directly from a computeraided design (CAD) model. The CAD design is transformed into horizontal cross-section layers that are stacked together in physical space until the physical model is completed. This process can be used to directly manufacture tools for injection molding or for an y other technology that requires a specific cavity shape to produce a part. This is referred to as Rapid Tooling (RT) and one of the up and coming
AM technologies is the resin based stereolithography (SLA).
An increasing number of companies are starting to develop desktop machines that utilize this technology and their low cost an d high speed changes the design workflow. As a printing technology, SLA creates parts with a smooth surface finish which is ideal for applications such as investment casting for developing jewelry or rapid tooling for injection molding.
The development of rapid tools using SLA usually requires more rigid materials which can withstand higher temperatures and stresses and part models that need to have more accurate dimensions in order for a precise part to be produced from that specific tool. Even though models created by SLA have more isotropic characteristics compared to other 3D printing technologies, there are still some variations linked to the process parameters. This paper covers how orientation of the model on the build plate impacts the pa rt accuracy and the tensile strength of the models. The effects of different post-processing procedures after SLA printing are also taken into consideration, since most resins need to be UV cured after 3D printing in order to achieve maximum mechanical strength.
This paper gives designers and engineers better understanding on the final properties of the models and the tolerances that have to be taken into consideration when designing parts intended to be manufactured via SLA 3D printing.