Study On The Influences Of Plastic Flow On Microchannel Formation Under Temperature And Pressure

Continuous development of microchannel formation technology enhances the applications of microfluidic chips in biology and chemistry field. In order to meet the demand of bio-chemical analysis on microfluidic chips, it is foremost problem to fabricate high quality microchannels for accomplishing microfluidic chips' function. This paper mainly studies on the influences of plastic flow on microchannel formation in following aspects including theory analysis, simulation and experimental verification. Optimizing experiments are carried out to obtain preferable processing parameters.This paper applies linear viscoelastic theory to study on the creep and relaxation phenomena and to verify the relaxation behavior through several stress relaxation experiments. Maxwell model is adopted to conduct the relationship of plastic between strain and time in the process of microchannel formation. Compared to experimental curve, the same trend is gained. Then plastic flow mechanics are depicted in three aspects as follows: heat transfer, physical state changing and viscoelastic formation. Plastic flow in thermal-stress field is simulated by ANSYS software. According to simulation results, plastic flow experiment and microchannel formation experiments are carried out. Experimental results certify simulation conclusions.Simulation conclusions and experimental verification provide guidance for selecting processing parameters in following aspects. Formation temperature should be selected above glass transition temperature to assure adequate flow of plastic. Larger force makes microchannel replicate entirely. Preserving time of temperature and pressure is needed to make plastic flow in every part coherent.Based on foregoing researches, this paper conducts optimizing experiments. Preferable processing parameters are gained by evaluating the relative errors of height, width and shape in the sixteen orthogonal experiments. Then five repeated experiments are carried out with preferable processing parameters. Experimental results prove that shapes and dimensions of microchannel have good stability. Microchannels of two different PMMA bulk materials are fabricated after achieving their characteristic changing temperatures. Microfluidic chips are gained by bonding microchannels. Chips are supplied to customers. Experimental results indicate that preferable microchannel can meet separation requirements better.