Preparation And Mechanical Properties Of Fiber Reinforced 3D Printed Composites

As a kind of intelligent manufacturing technology based on Internet of things,3D printing has developed rapidly in recent years in the industrial field.However,the strength of 3D printing molding components with polymer as consumables is generally low,which limits the application range of products.Fiber-reinforced 3D printing composite materials for the development of 3D printing technology provides a new way of thinking.The fiber-reinforced 3D printing composite material was fabricated by the combination of short fiber,filament and yarn,through the powerful advantages of high-performance fiber to improve the overall strength of forming components to expand the application of 3D products.In this paper,based on the study of the forming principle of light-cured 3D printing technology,an automatic circulation stirring system is added to the original 3D printing equipment,which can make the new equipment to prepare the short fiber reinforced 3D printing composite material,a set of preparation process of short fiber reinforced 3D printing composite material is designed.The dispersion uniformity of the short fibers in the short fiber photosensitive resin suspension was studied.The short fiber reinforced photo-curable 3D printing composites were successfully fabricated and the mechanical properties and interface of the composites were studied and analyzed.The distribution of polylactic acid(PLA)monofilaments in 3D printing components was studied by analyzing the characteristics of the fused deposition 3D printing technology.Different types of standard tensile specimens were prepared.The effects of the diameters,arrangement densities and arrangement of polylactic acid monofilaments on the mechanical properties of standard specimens were analyzed.The characteristics of light-curing 3D printing technology in the production of three-dimensional space model were studied.Added a set of yarn weaving system in the original light-cured 3D printing equipment So that the new device can prepare three-dimensional braided light-cured 3D printing composite material,the preparation technology of three-dimensional braided photo-curable 3D printing composites was designed.The effects of the different dimension yarn systems on the mechanical properties of the composites were analyzed.The main conclusions are as follows:(1)In the experiments,automatic circulation mixing system was added in the 3D printing equipment.The short fiber-reinforced photo-curable 3D printing composites were successfully fabricated using chopped carbon fibers with lengths of 1 mm,3 mm and 5 mm respectively.The mechanical properties of the composites were analyzed,the results show that the composites with 1 mm and 3 mm chopped carbon fibers have a lower tensile strength and a higher tensile strength at 5 mm shorter than that of the pure photosensitive resin.When the length of the chopped carbon fiber is 1mm or 3mm,the tensile strength of the composite decreases with the increase of the mass fraction of carbon fiber.When the length of the chopped carbon fiber is 5mm,the tensile strength of the composites increases with the increase of carbon fiber mass fraction.The more uniform the distribution of carbon fiber in the composites,the better the mechanical properties of the composites,and the more obvious the reinforcing effect of the carbon fiber.(2)The working principle of FDM 3D printer is explored,and the printing temperature of PLA wire is studied.The effects of compactness and arrangement of different single filaments on the mechanical properties of the formed members were investigated.The results show that,the diameters of 0.2 mm and 0.4 mm nozzles do not affect the tensile strength of the filaments of large diameter PLA filaments ejected by FDM type 3D printers.With the increase of the packing density,the tensile fracture strength of the FDM type 3D printing member is increasing;When the packing density is 100%,the arrangement and diameter of the PLA filaments with large diameter do not affect the tensile fracture strength of the FDM type 3D printing member.When the packing density is less than 100% and the nozzle diameter is the same,tensile strength of the tensile fracture is characterized by: The tensile strength of the PLA filament was the highest when the PLA filament was arranged in a concentric way.The tensile breaking strength of the PLA filament was arranged in a linear manner and the tensile strength of the PLA filament was the smallest.When the packing density is less than 100% and the PLA filament arrangement is the same,the tensile breaking strength of the 0.2 mm PLA filament is higher than that of 0.4 mm PLA filament.(3)By combining three-dimensional weaving technology and light-cured 3D printing technology,three-dimensional braided photo-curable 3D printing composites were prepared.The carbon fiber yarn,the high strength polyethylene yarn and the glass fiber yarn are respectively cured in the photosensitive resin after the interweaving.Dimensional yarn system and the three-dimensional yarn system are respectively combined with the photosensitive resin to prepare the composite material,The mechanical properties of the composites were analyzed.The results show that,the three-dimensional braided light-cured 3D printing composites embedded in woven yarns have higher tensile breaking strength than pure photosensitive resins,and the strength of the composites embedded with high strength polyethylene yarn increased by 185.9%,the strength of the composites with the glass fiber yarns increased by 84.2%,the strength of the composites with embedded carbon fiber yarn increased by 22.7%.The three-dimensional braided light-cured 3D printing composites embedded in woven yarns have higher elastic modulus than pure photosensitive resin,and the composite material embedded with high strength polyethylene yarn increased by 197.58%,the glass fiber composite yarns increased 164.55%,the composite material with carbon fiber yarns embedded in the composite material increased by 151.51%.Photosensitive resin to the high-strength polyethylene yarn and glass fiber yarn penetration within the solid state and better shape.Photosensitive resin to the carbon fiber yarn penetration but not fully cured,curing form is poor.Compared to two-dimensional yarn systems,three-dimensional yarn system can be woven through the winding between the yarn can make the composite structure to maintain integrity.