Research On The Quality Improvement Of Advanced Pultrusion Products Process

Depending on high specific strength and modulus,the designability of material and structure,good fatigue resistance and other advantages,advanced resin matrix composites get widely used in aerospace,wind power,automobile,medical and other high-tech fields.With the increasing usage of composite materials in different areas,the manufacture of composite profiles is getting more and more important.Advanced pultrusion,referred to ADP,as a new technology for the manufacture of composite with a high efficiency and low cost,has been able to produce a variety of composite profiles after years of development.ADP has been one of quite mature technologies,and commercialized in foreign countries.But only a few years for domestic research,the quality of ADP products is lower than abroad.Based on the ADP research,this paper analyzes the causes of the defects of the parts,and puts forward the optimization process,the quality of the parts finally getting improved.The main content of this paper is summarized as follows:(1)Analysis of defects in ADP products with the development of domestic ADP technology in recent years: domestic researches have developed C type beam,cap type beam,“?” type half pod rod,ADP equipment also has two generations of development,but thickness of the product hard to control,fiber distortion,surface step pattern and other defects,always exited in the profile.These defects will undoubtedly affect the surface quality and performance of the profiles,pushing the composite performance advantages down.(2)A thorough study for recent years found that the parts thickness,fiber distortion,step grain,are related with the resin flow: under the effect of pressure,the resin flows out prepreg,the resin content being reduced and hard to control;outflow resin accumulates at the entrance of the mould,in the subsequent thermal curing,the accumulating resin translates into step grain;the flowing resin strikes and sticks fiber,finally gets fiber deviate from its original position,with resin being cured,fiber is located,wrinkle comes into being.(3)In order to ensure the performance of the parts,solve the above defects,putting forward the optimization scheme of ADP : It is clear that these defects are caused by the flow of resin,this paper consideres this method to optimize the process:adding pretreatment process and pre-curing process,increasing prepreg viscosity before prepreg is sent to hot pressing die.If prepreg viscosity gets increased,resin mobility of the prepreg being smaller,there will not be too much resin flows in the process of pressure,thereby eliminating the defects.(4)Taking the bending strength,shear strength,and the final resin content as the test standard,orthogonal test was used to find out the optimal combination of the parameters for USN12500 prepreg laminate: 90??85min?0MPa,110??15min?0.2MPa,130??15min?0.8MPa.The mechanical properties of ADP products are basically flat with molding products,and the surface quality is higher than the profiles which were made by old ADP process.