| Micro-fluidic technology is a technology that manipulates fluids in flow channels of hundreds of microns or smaller to complete various experiments.It can achieve high-resolution separation and detection using trace samples or reagents.The micro-fluidic chip is an important device to realize micro-fluidic technology.The processing materials,processing methods and roughness in the flow channel of the micro-fluidic chip are undoubtedly the most critical issues in the development of micro-fluidic technology.The advantages of polymer materials,such as wide source,variety and easy processing,have been paid attention by micro-fluidic chip researchers.At the same time,its processing method,micro-injection molding,has also attracted the attention of micro-fluidic chip manufacturers because it can achieve continuous production.In this paper,by studying the injection process of the micro-fluidic chip,the orthogonal analysis method was used to analyze influence of the melt temperature,mold temperature,injection speed,and holding pressure on the micro-fluidic chip injection molding process to determine the best injection process.At the same time,the micro-fluidic chips were formed under the optimal injection molding process,and they were used for liquid mixing experiment and droplet forming experiment.There are four main contents and conclusions of this paper as follows:(1)In the light of the processing accuracy of the injection mold and the characteristics of the droplet generation device and the liquid mixing device,the size of the flow path of the droplet generation device was determined to be 500?m × 500?m,and the flow size of the liquid mixing device was 400?m×400?m.Using professional software COMSOL,the simulation of liquid mixing and droplet generation was carried out.The simulation results confirmed that when the cross section of the flowing path of the droplet generation device was 500?m × 500?m and the velocity of the dispersed phase fluid was 1/2 of that of the continuous phase fluid,the micro-flow stable droplets were formed in the channel.When the cross section of the flow channel of the solution mixing device was designed to be 400?m× 400?m and the liquid mixing velocity is 5?L/min,the liquid mixing effect was good.The micro-fluidic chip was designed according to the simulation results.(2)The mold design was carried out according to the characteristics of the injection molding process and the structure of the micro-fluidic chip.The mold filling process of the micro-fluidic chip was simulated and analyzed using Moldflow software.The results show that the designed mold can meet the molding process of the micro-fluidic chip,and it also shows that the pouring system and the heating system were reasonable.(3)Orthogonal experiments were used to conduct an experimental which studys on the injection molding of the micro-fluidic chip.By using the opening width,groove depth,and bottom width of the single-channel test device of the micro-fluidic chip as indicators,there was analysis the influence of the injection molding process on the injection molding of the single-channel test device in the micro-fluidic chip,and there was obtaine the best injection molding process parameters of the micro-fluidic chip in the selectable range.Compared with the micro-fluidic chip formed by CO2 laser processing,it is concluded that it was more advantageous to use injection molding to process the micro-fluidic chip.(4)Useing the micro-fluidic chip formed in the best injection molding process to conduct liquid mixing experiments and droplet generation experiments to verify the functionality of the micro-fluidic chip under injection processing conditions.Compared with the micro-channel processed by CO2 laser,it was found that the micro-fluidic chip produced by injection molding can better meet the requirements of the micro-fluidic experiment. |
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