Multiobjective optimization of Nd:YAG direct laser writing of microchannels for microfluidic applications

Abstract

After entering the twenty-first century, there has been an ongoing drift toward miniaturization of discrete products in several areas. One such application is microfluidic device used in biomedical applications. The challenge with the manufacturing of microfluidic devices/biochips is that they often make use of broad range of materials within a single chip, making it difficult to manufacture these devices with conventional photolithographic-based techniques. Laser processing of materials has proved to be an important tool for the development of these devices because of the accuracy, flexibility, and the most important one material independence it offers. In this work, laser direct writing technique is used for the fabrication of microfeatures in AISI 1045 steel for the microfluidic applications. The basic purpose of the research work is to assess the performance of direct laser machining for the development of microfluidic channels by investigating the effects of different process parameters using design of experiments (DOE) and regression modeling analysis. The model is developed with Optimal Design IV in Response surface methodology taking five input parameters including the scan strategy which is mostly overlooked in the past research. Analysis of variance (ANOVA) has been carried out for five performance measures namely width error for rectangular section, width error for semicircular section, taper degree, recast layer, and material removal rate. Multiobjective optimization of these performance variables has been carried out, and it has been shown that optimized solutions are obtained at moderate frequencies, high scan speed, and minimum layer thickness.