| Carbon fiber composite materials have the advantages of high strength and light weight,and are widely used in aerospace,electronics,mechanical and chemical industries,automobiles and sports equipment.Injection molding is one of the important molding methods of carbon fiber composite materials,in which the choice of process parameters has a great influence on the quality of plastic parts.Especially the effect on fiber orientation is related to the final mechanical properties of the plastic.Therefore,how to effectively control fiber orientation,optimize fiber distribution in products,and obtain products with better performance is the key to controlling the performance of plastic parts.At present,in the injection molding process,most studies use factors such as changing the viscosity of the compound,the injection speed,the smoothness of the cavity,and the geometry of the mold to optimize the fiber orientation,but this is qualitatively controlling the fiber orientation and controlling the fiber orientation.Limited,this article intends to propose an injection molding scheme under the action of an external magnetic field on the basis of the traditional injection molding process to optimize the fiber orientation during the molding process to obtain products with better performance.This paper proposes a method to optimize the fiber orientation in the injection molding process,and has made a lot of research in process design,process optimization and experimental verification.The specific research done in this paper is as follows:(1)Based on the composite material flow theory and the principle that magnetic particles will be subjected to magnetic field force in the magnetic field and move in the direction of the magnetic field,an injection molding compound process under the action of an external magnetic field is proposed.The process aims to optimize the fiber distribution inside the product and obtain products with better mechanical properties.(2)In this paper,for the standard tensile specimen model and 25% carbon fiber PC material,Moldflow software was used to analyze and determine the best gate location,and a three-dimensional analysis model was established.Using orthogonal test methods,16 groups of different process parameter combinations were respectively analyzed.Simulation,the results are obtained,and the simulation results are statistically analyzed,and the degree of influence of each process parameter on fiber orientation is determined as injection pressure>melt temperature>mold temperature>injection time,and the best injection molding process combination is the mold The temperature is 110?,the melt temperature is 300?,the injection time is 3.0s,and the injection pressure is 180 MPa.(3)In this paper,based on the best combination of injection molding process parameters obtained by CAE simulation,a new impact factor carbon fiber nickel plating content is introduced,a new orthogonal injection molding experimental scheme is established,a magnetic field condition is introduced,and the nickel content is 0,20%,40 %,60% PC-based nickel-plated carbon fiber composites made of nickel-plated carbon fiber were used for injection molding experiments.The tensile and bending tests of the test piece and the observation of the surface fiber structure were carried out.It was concluded that when the carbon fiber nickel plating content is 40%,the tensile strength of the injection molded product under the magnetic field is the highest,compared with the non-magnetic field injection molded product The tensile strength is increased by about 15%,indicating that after the optimization of magnetic field-induced injection molding,the internal structure of the product is more uniform,the tensile strength of the test piece is improved,and the bending strength is also improved. |
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