Experimental Research And Simulation Analysis On Glass Molding Process For Microfluidic Grooves

Microfluidic chip technology is a technology characterized by sub-millimeterscale fluid engineering operations,which are considerable prospect in improving medical diagnostic efficiency and biological research.The conventional processing methods of glass chips,such as photolithography and wet etching,require not only numerous processing steps,high cost,but also difficulty in achieving high-precision preparation,which limits the possibility of mass production.Glass molding process(GMP)is simple in process,capable of efficiently replicating and processing.It can stably produce micro-structures with complex surfaces in a large batch,which provides a new method for glass microfluidic grooves process.According to the difficulties of micro-structure die processing,glass molding accuracy and surface quality are difficult to control accurately.This paper studied the molding process of typical microfluidic grooves in glass microfluidic chips.Based on the generalized Maxwell model,a simulation model was established on the platform of the non-linear finite element software MSC.Marc.The forming process of soda-lime glass was simulated,and the effects of molding temperature and rate on microfluidic groove depth and filling rate were analyzed.Finally,the validity of the simulation model was verified by experimental results.The main contents are as follows:(1)A machining process for tungsten carbide die was studied by using femtosecond laser.Influence of three factors,scanning power,scanning rate,scanning layer on surface roughness and material machined depth were studied by orthogonal test.Through a comprehensive optimization of those results,optimal process parameters are obtained.The biggest factor affecting machined depth is scanning rate,and the minimum factor is the scanning power.The processing depth would experience a remarkable growth under either of the three circumstances: femtosecond laser power increases.The scanning speed decreases,or the number of repeated scans increases.In selected parameters,those variations of each parameter have little effect on the surface roughness.Therefore,by selecting high power and low scanning rate,a fine microfluidic grooves die with better machining surface quality can be prepared,meanwhile,the machining efficiency can be ensured.(2)Combined with the non-linear simulation software MSC.Marc,the process of glass microfluidic grooves molding was simulated.The effects of molding temperature and rate on maximum residual stress,reduction pressure and filling rate in the pressing stage were compared and discussed.It is found that the maximum residual stress is negatively correlated with the pressure temperature,and the maximum residual stress decreases with the increase of temperature,and tends to be constant when the temperature rises to 640?.The maximum residual stress of the micro-forming flow increases with the increase of the pressure rate,which shows an approximate exponential growth relationship.According to the research on the influence of molding temperature and rate on the microfluidic groove depth,the higher molding temperature and the smaller molding speed,the greater microfluidic groove depth and the better filling rate after the end of the pressing stage.(3)Compared the process parameters of the simulation model,the GMP experiment was carried out.The results show that increasing the molding pressure and temperature can improve the filling rate and microfluidic groove depth.The experimental results are consistent with the trend of the simulation data analysis,which proves the validity of the simulation model.