Study of Optical Components for the Automotive Industry ^†

This work aims to study the injection of molded optical components for the automotive industry produced by an injection molding plastic company. During the production process, undesirable defects appeared at critical locations on the optical surface. The problem occurred inside the assembly line site and an analysis was performed in-line. After appropriate measurements and data collection in the instant of a spur interfering with laser cutting, air blowing was considered to be the cause of the existing defects. Computational Fluid Dynamics (CFD) and Design of Experiments (DOE) tools were used with the aim of finding the parameters associated with the air compressed hosepipes, to indicate and characterize the optimal conditions for the problem’s solution [1,2,3]. Most relevant objects from the experimental scenario were modelled (Figure 1) and the same blowing air conditions were simulated with Computer Aided Design (CAD) and CFD software tools, respectively.

Further simulations (two-level full factorial design with the addition of center points) were performed to evaluate the air flow velocities through the spur cut section plane, to determine the height, angle, and blowing air velocity influences as potential factors related to the existing problem. Based on the obtained results, it was observed that higher blowing air from hosepipes, lower distances to the component, and higher reference angles improved the conditions of the blowing air flow at the spur cutting zone, in this case to a better setup than before. Statistic results from DOE demonstrated that the height was the critical factor to reach higher flow velocities in the cut plane and consequently more efficacy in particle removal and fewer defects [4]. At the end of this work, recommendations about further works are suggested, which consider the fact that the simulations performed during the study only indicated approaching conditions, requiring further validation through the execution and verification of the blowing air, resulting in values for parameters within the real components’ assembly production site.