Research On Key Technology Of Hot Pressing Molding Of Polymer Micro Channel Array Substrate

Due to its miniaturization,high flux and automation,and many other advantages,biochip obtained rapid development since the late 1980 s.The category of biochip increased progressively,the requirement of molding quality is higher and higher.Polymer micro channel array substrate is one kind of biochip for detecting and obtaining biological information.384 array cylindrical chambers with 1.4 mm in diameter and 0.55 mm in height,8 elliptical cavities,8 sampling holes,4 locating holes,8 main channels and a plurality of branch channels are designed on the surface of it.The Polymer micro channel array substrate requires high dimensional precision and thin thickness.It needs to solve such problems as dimensional accuracy and shape accuracy that are difficult to control in the process of hot pressing molding.Firstly,in order to improve the dimensional accuracy of polymer micro channel array substrate after hot pressing molding,research on influence of hot pressing process parameters on polymer micro channel array substrate shrinkage laws,the hot pressing mould was designed preliminary based on the structural features of polymer micro channel array substrate.Then the optimal shrinkage rate of mould was determined by the scheme of orthogonal experiment.The shrinkage range of qualified hot pressing molding polymer micro channel array substrate was simulated by UG 9.0.Secondly,on the basis of the above research,in order to improve the control precision of hot pressing temperature,the hot pressing mould temperature field was simulated by ANSYS Workbench.Then,the position of heating rod was optimized based on the results of simulation,and the design of temperature control box was completed.The new-type hot pressing mould was designed and manufactured with further optimize the mould structure.In order to realize deeply the hot molding process of polymer micro channel array substrate,the material model of CPP thin film which was used to mold polymer micro channel array substrate was characterized by two parameters Mooney-Rivlin model,the influence of hot pressing process parameters on the filling behavior of CPP thin film was simulated by ANSYS Workbench.The results indicated that,the filling rate of CPP thin film can be improved by increasing the hot pressing temperature and hot pressing pressure,and the effect of hot pressing pressure on the chamber depth decreases with the increasing of hot pressing temperature.Finally,the influence of hot pressing process parameters on the molding quality of micro channel array substrate was analyzed by the refinement experiment of process parameters.The optimum process parameters of hot pressing molding polymer micro channel array substrate with new-type hot pressing mould are determined,and the distribution of residual stress was analyzed by means of polarization stress meter.The results show that,the main factor that affects the quality of polymer micro channel array substrate is hot pressing temperature.With the increasing of the hot pressing temperature,the diameter of the cylindrical chamber and the transmittance decrease gradually,cross-sectional warping increases gradually.However,with the increasing of hot pressing pressure,the transmittance increases gradually.Cross-sectional warping decreases with the extension of hot pressing time,and the hot pressing time has little influence on the transmittance of polymer micro channel array substrate.The residual stress distribution of CPP thin film is more uniform before hot pressing molding,and then the non uniform residual stress is distributed in the elliptical chamber and cylindrical chamber region after hot pressing molding.