Research And Application Of Carbon Fiber Composites For 3D Printing

The combination of carbon fiber composites and 3D printing technology can give full play to the performance advantages of carbon fiber composites and the molding advantages of 3D printing technology,which has broad development prospects.The purpose of this project is to develop a carbon fiber reinforced polyester composite,and study the key preparation technology of polymer wire for 3D printing equipment,as wel l as the application of the material.The engineering plastic PET was selected as the polymer matrix,and the mechanical properties of the material were reinforced by carbon fiber.PET will be modified and the processing technology will be optimized.The development of this project expands the application of carbon fiber composites in 3D printing forming technology,enriches the variety of 3D printing polymer wire series products,provides a new material with excellent performance for the market,provides a functional material for the application of 3D printing in the engineering field,and endows 3D printing products with higher functionality,which will promote the new development of 3D printing technology in engineering Application becomes possible.In this project,PET is selected as the matrix resin.PET and carbon fiber were used to prepare composites,and the extrusion process of the composites was explored.Thus,a kind of carbon fiber reinforced polyester composite material is prepared,which is suitable for 3D printing equipment.The details are as follows:1.Based on the melt stacking technology(FDM),the effects of printing parameters such as printing temperature,printing speed,and fan on the tensile strength of 3D printed polylactic acid splines were studied.The main printing parameters are: printing temperature,printing speed,and fan.The tensile strength of PLA printed along the x-axis is 47.90 MPa when the printing temperature is 200 ?,and that printed along the z-axis is 25.14 MPa when the printing temperature is 205 ?.When the printing speed is 20 mm / s,the tensile strength of PLA is the highest.The reason may be that when the printing speed is 40 mm / s,the crystallization of PLA is poor,which affects the tensile strength.When the fan is turned off,the tensile strength of PLA is higher.There are many factors that affect FDM 3D printing.Only when the interference of printer parameters is excluded,can the influence of material formula on 3D printing be fully studied.The results of this chapter can be used to exclude the influence of equipment selection or parameter change on material formula in subsequent research.2.Polyethylene terephthalate(PET)was selected as the matrix material,and the PET wire suitable for melt deposition technology was prepared by adding PBT,compatibilizer,toughener and nucleating agent.It was found that the wire material obtained at a PET/PBT weight ratio of 7/3 presented the lowest melt flow rate.The addition of too much compatibilizer resulted in bridging at the screw inlet,which was disadvantageous to screw extrusion.The results obtained from the 3D printing and mechanical measurement indicated that the wire material could be normally printed at a content of toughening agent of 15 phr.The wire material achieved tensile strength of 25.95 MPa,bending strength of 45.99 MPa,and impact strength of 50.4 k J/m2.Adding0.5phr talc powder can improve the mechanical strength better3.Carbon fiber powder was used to modify polyester material to prepar e carbon fiber composite polymer wire suitable for melt deposition 3D printing.The reinforcing effect of carbon fiber with different particle aspect ratio and different content on polyester substrate was studied.The mechanical properties and friction and wear properties of 3D printing spline were discussed.The results show that: 1)when the carbon fiber content is 5 phr,the tensile strength of the composite reinforced by carbon fiber with short aspect ratio is the best,which is 27.2 MPa.The tensile strength decreases with the increase of carbon fiber content from 5 phr to 15 phr.2)The friction coefficient of carbon fiber / polyester composites first decreases and then increases with the increase of aspect ratio,and the wear scar width decreases with the increase of aspect ratio.The friction coefficient of carbon fiber / polyester composites first increases and then decreases with the increase of carbon fiber content.The wear scar width increases with the increase of carbon fiber content.When the c arbon fiber content is 15 phr,the wear scar width reaches 14.97 mm.4.The warping deformation of carbon fiber polyester composites during the process of melt deposition is analyzed.When the content of carbon fiber is the same,the smaller the aspect ratio of carbon fiber is,the less prone the composite to warp.The warpage height of the printed parts decreases with the increase of carbon fiber content.Through the establishment of theoretical model,the main parameters affecting the warping deformation are analyzed.The results show that the main parameters affecting the warping deformation are linear length L of the parts,linear shrinkage constant coefficient ? of the wire,glass transition temperature Tg,ambient temperature Te of the molding room,number of printing layers n and thickness of printing layer ?h.Using glue on the printer bottom plate can increase the adhesion between the print and the bottom plate,so as to reduce the warpage.