WEB Optimization of Direct Laser Interference Process using design of experiments approachWednesday (23.09.2020) 12:05 - 12:20 F: Functional Materials, Surfaces, and Devices 2 Part of:
Surface topographies with well-defined microstructures and uniform distribution of contact points are required in many applications to obtain or optimize the desired surface functionality. In this study, we report on the optimization of Direct Laser Interference Patterning process by applying design of experiments approach. The periodic line-like microstructures of 8.50 µm spatial period were fabricated by a two-beam interference setup with nanosecond laser pulses, varying laser fluence, pulse overlap, and hatch distance. Central composite design with three factors and five levels was implemented to optimize the required number of experiments. The experimental and numerical results show the impact of various structuring process parameters on surface uniformity. The responses measured are structure height, height error, and waviness of the structure. Large-area analysis of microstructures was conducted by confocal microscopy and scanning electron microscopy. A 3D-characterization method based on morphological filtering, which allows a holistic view of the surface properties, was applied and a new qualification scheme for surface microstructures was introduced. Empirical models were also developed and validated for establishing relationships between process parameters and performance criteria. Multi-objective optimization was performed to achieve a minimal value of structures height error and waviness.