Research On PMMA Micro Milling Material Removal

Polymer is widely applied in electronics,optics and medical industries.These products usually require polymer parts with micron and sub-micron accuracy.How to achieve fast,reliable,reproducible,and high-quality product is essential for mass application of polymer parts.At present,the manufacturing of polymer products is still mainly through traditional processing methods such as hot pressing,injection molding,carbon dioxide（CO₂）laser etching and photolithography.The parts manufactured by these methods usually have low precision,poor surface quality（surface roughness Ra>300 nm）,and poor reproducibility.Therefore,a method that is efficient,accurate,and highly repeatable for mass production of polymer parts is in need urgently.As an efficient and repeatable manufacturing method,micro-milling is particularly important in the field of polymer manufacturing.Traditional micro-milling is mainly used in the manufacturing process of traditional materials such as metal,but research on polymer materials is not enough.In this thesis,the removal characteristics of polymer materials in mechanical processing are mainly studied through the removal characteristics of PMMA micro-milling.It may contribute to further understanding of polymer cutting.This article firstly studied the mechanical properties of PMMA thermoplastic polymer materials.Through the PMMA micro-milling process experiment,the processing and manufacturing characteristics of PMMA were studied.Through ABAQUS finite element simulation,the chip formation process of PMMA material micro-milling was studied,which might provide a certain theoretical support for the polymer cutting process.The main research contents of this article are as follows:（1）Through static compression and dynamic Hopkinson Pressure Bar experiments,the characteristics of PMMA materials were studied,and the J-C constitutive model of PMMA materials was constructed by fitting.The prediction accuracy of the model for the yield plasticity stage of PMMA materials was about 80%.（2）The effect of micro-milling parameters on PMMA processing was studied through experimental methods.Through the combination of experiment and simulation analysis,it was found that the chip was mainly in the shape of"roll"when the temperature was below 60℃,when the temperature is 60-75℃,the chip shape was"sheet",and the chip shape was"Sintered"when the temperature is larger than 75℃.（3）Through the ABAQUS finite element simulation of the PMMA polymer material micro-milling process,the formation mechanism of sheet and roll chips was clarified.This research would contribute to the further understanding of polymer cutting process.