Research On The Law Of Hot Compression Molding Of Polymer Film Microfluidic Chip

The polymer film microfluidic chip is mainly used for biological information detection.Its surface is designed with 8 groups of detection channels.Each group of detection channels includes a polygonal liquid inlet chamber,a main channel,48 cylindrical reaction cells and 48 The flow diversion channel has a complicated structure,and its molding quality has a great influence on the detection effect.To this end,conducting in-depth research on the problems of precise control of the shrinkage rate of polymer film forming and the forming quality of cylindrical reaction cells in this paper.Firstly,for the problem that the dimensional accuracy of the polymer film microfluidic chip molding process is difficult to accurately control,each process parameter in the hot pressing process is divided into fine levels.The design and implementation can reflect the influence of each process parameter on the shrinkage rate.Orthogonal experiment and regression analysis of the experimental data to quantify the relationship between each process parameter and shrinkage.The experimental results show that the hot pressing temperature is the main factor affecting the shrinkage of the microfluidic chip,followed by the holding time,and the hot pressing pressure has the smallest effect.Increasing the hot pressing temperature or extending the holding time can increase the shrinking rate.Secondly,on this basis,calculate the size of the die and die of the mold,and add the automatic cutting function,redesign and manufacture a new type of hot press forming mold,and a device for preheating the polymer film.The experimental results show that the new hotpress forming mold can ensure the dimensional accuracy of the microfluidic chip,the microstructure is completely formed,the cutting process can be automatically completed and the cross section is clean;the preheating process can improve the surface quality of the microfluidic chip and eliminate its surface stress Concentration phenomenon.Thirdly,in order to study the forming rule of the microstructure of the cylindrical reaction cell,the drawing deformation zone of the microstructure is divided into the flange area,the concave mold corner area,the barrel wall area,and the convex mold with reference to the drawing process of the metal material The five areas of the rounded corner area and the bottom area of the cylinder are used to analyze the material flow in each area according to the change in material thickness in each area.The experimental results show that the thickness of the flange area does not change during the deep drawing process of the cylindrical reaction cell and does not participate in the deformation process;the thickness of the barrel wall area and the bottom area of the barrel are both thinned to a large extent,and the thickness of the barrel wall area becomes The greater the thinness,the greater the degree of material deformation;the convex corner area and the concave corner area are two transition areas.Finally,in order to eliminate the inconsistency of the forming depth of the microstructures on both sides of the microfluidic chip due to the deviation of the pressure center during the pressing of the microfluidic chip using the new hot-pressing mold,a ball hinge-like pressure was proposed and manufactured Self-balancing mechanism.The experimental results show that the pressure self-balancing mechanism can effectively improve the pressure unevenness during the hot press molding process.The microstructures of the formed microfluidic chip are formed uniformly and completely everywhere,and the overall residual stress distribution is uniform.This research content and achievements have certain practical significance and application value for improving the quality of polymer film microfluidic chip molding process and promoting its wider use in the industry.