Research On Extrusion Process And Mechanical Properties For PLA/CF Composite

Carbon fiber reinforced polylactic(PLA/CF)composite is a new high-strength degradable material,which combines the excellent properties of PLA and CF.PLA is used as the matrix material and CF is used as the reinforcement material.By changing the processing technology or by CF surface modification,the properties of PLA can be continuously improved to meet the application requirements.After years of development,3D printing technology has become a common process to prepare composite materials.Among all kinds of 3D printing technologies,pneumatic extrusion3 D printing has a large number of applications in the fields of plastic product preparation and biological 3D printing due to its advantages of simple process,controllable materials and low cost.However,due to the limitation of extrusion force and poor interface bonding,the mechanical properties of the products prepared are relatively poor.Therefore,it is of great significance to carry out the research on the pneumatic extrusion 3D printing in the field of composite materials to improve the mechanical properties.Based on the interface theory and mechanical properties analysis of PLA/CF composites,the process and mechanical properties of the 3D printing system of PLA/CF composites were studied in this paper1.The rheological properties of PLA/CF composite were studied,and the simulation model of the composite was analyzed.A nozzle suitable for 3D printing system of air pressure extrusion was designed.The precision of nozzle diameter is ensured by laser processing,and the material ratio,basic printing parameters and technological research parameters were determined.2.The influence of 3D printing process parameters on the mechanical specimens of composite materials was studied.The mechanical properties of the composites were tested by using the 3D printing system.The mechanical properties of carbon fiber,nozzle diameter and layer thickness were compared by using the control variable method.The influence of different printing path and load direction on the mechanical strength of the specimen was also studied.The fracture morphology of the tensile specimen was characterized by SEM.Through the comprehensive study of the mechanical properties of the printing specimen,the optimal printing process for the material preparation was determined.3.The effect of CF surface treatment on the mechanical properties and interface adhesion of PLA/CF composite was studied.The surface oxidation and coating modification were used to modify the CF powder.Firstly,the specific surface area and surface morphology of the modified carbon fiber powder were characterized,and the mechanical specimens were prepared based on the optimal printing parameters.Then,the mechanical properties of the modified PLA/CF composite were tested.Finally,the change of the interface bonding morphology of the composite was investigated by SEM,and the results showed that the modified carbon fiber powder was suitable for the modification.The surface treatment method of 3D printing composite CF reinforced material by CO air extrusion.