Research On Electronically Controlled Thermal Deformation 4D Printing Technology

4D printing is an emerging technology developed on the basis of 3D printing technology in recent years.It adds a time dimension to 3D printing,and uses shape memory smart materials to realize self-building and re-assembly.The polylactic acid material studied in this study has biocompatibility,high tensile strength,outstanding biodegradability,shape memory function,and good application prospect in biomedicine.At present,many researchers at home and abroad have conducted research on polylactic acid materials,using fused deposition 3D printing technology to print,and the prints can be autonomously deformed in an elevated temperature environment.However,at present,most of the experiments are heated by hot water.On the one hand,it is difficult to control and maintain the hot water temperature.On the other hand,the water environment limits the development and application of such materials.This topic uses the method of theoretical analysis,simulation and experimental research to combine polylactic acid shape memory polymer with copper wire for 3D printing,and conducts related technologies through experiments and simulations.By energizing the composite copper wire,the polylactic acid shape memory polymer is heated.In this way,the deformation mode is switched from temperature control to electronic control.The specific research contents are as follows:Based on the theory of polymer phase transition and the basic principle of 3D printing for fused deposition,the polylactic acid polymer can be made into a 4D printed wire material through a hot extruder to facilitate subsequent printing experiments;the optimization is based on the traditional print heads.Two kinds of 4D printheads,one-piece printheads and separate printheads,to achieve arbitrary ratio printing of metal wire composite layers and pure polymer layers;design motion platform,path planning system and control system of electronically controlled thermal deformation 4D printers to ensure Subsequent printing experiments proceeded smoothly.Based on the finite element principle,the COMSOL software was used to perform finite element simulation on the 4D printing process and the shape recovery process of the printed workpieces.The thermal simulation analysis of the 4D printing nozzles was first studied to analyze the thermal distribution of the print heads,to find the best printing temperature,and the print heads and printing platforms.Good printing distance,and provides a theoretical basis for polylactide polymer modification optimization;then the polymer phase transition process simulation study,analysis of the arc axis caused by the over-large Young's modulus of the wire when printing circular arc The offset of the outside;Finally,the composite wire type and composite ratio of the printed workpiece are simulated to analyze the temperature distribution and shape recovery of the workpiece.The experimental verification of the 4D print control shape control simulation was conducted experimentally to further study the influence mechanism of print speed,print head and print platform temperature,print layer thickness and other print parameters on the neutrality of the wire,and the influence law.The effect of the composite ratio of composite layer and pure polymer layer on the recovery performance of the printed workpiece was analyzed,and the shape recovery performance of the carbon fiber-reinforced 4D printed workpiece was studied.