Injection Compression Molding And Visualization Research Of Microfluidic Chips

The injection compression molding (ICM) combined conventional injection molding and compression molding. It has absorbed the advantages of the two molding processes. Compared with the traditional injection molding, the injection compression molding has some advantages, such as minimizing molecular orientation, reducing birefringence of the optical parts, decreasing molding pressure, reducing residual stress, reducing density variation, increasing dimension accuracy, and so on. Because of these advantages, injection compression molding was employed to produce precision plastic parts such as optical discs, optical lenses and light guide plates. Injection compression molding of microfluidic chip is studied in this paper.Firstly, previous researches on injection compression molding and micro-fluidic chips were summarized. After literature collecting, the principle, characteristics and research techniques of ICM were understood. The previous research provided reference for ICM mold design and processing parameter research.Secondly, the ICM mold for microfluidic chips was designed. After structural design and calculation, the core compression ICM mold and the related control devices were designed. The pneumatic system was chose to be the power source of the compression devices. The wedge surface drive was designed to pass the power to the cavity. The pneumatic circuit and electric circuit were arranged to control the compression processing parameters. The visualization window in the mold offered necessary condition for visualization analysis.Thirdly, the single factor experiment was carried out. It was found that the bottom width and the depth of the microstructure were less influenced by the processing parameters than the top width. Therefore we focus on the top width of the microstructure. Both the injection parameters and the compression parameters were discussed and then the influence sequence of processing parameters was obtained.Lastly, the visualization experiments were performed. Schematic of the experiments was introduced and verified. The influence factor on the microstructure was researched by observing the flow behavior of the melt in the mold. The observation results agreed with the single factor experiments well. The filling process of the melt at the microstrcture provides an important guidance to the CAE and microscale effects research of the micro-structured parts.