Study On Mould Wear During Injection Moulding Process Of Glass Fiber Reinforced PEI

Glass fiber reinforced plastic is widely used in industrial production due to its low density,high strength,corrosion resistance,high temperature resistance,electrical insulation and strong designability.However,the fluidity of glass fiber reinforced plastic melt is poor,which requires high injection speed and pressure.In the injection moulding process of glass fiber reinforced plastic,the mould forming part surface is easily worn,which seriously affects the quality of the part.Therefore,the core wear in the injection molding process of glass fiber reinforced polyetherimide(PEI)was studied in this paper.According to the production practice,the micro wear characteristics of the core surface are analyzed.The erosion failure form and wear law of the core surface material,and the melt flow behavior near the wall of the cavity are studied by numerical method.On this basis,the adjustment method of mould structure parameters to control core wear is proposed.1.According to the production practice of glass fiber reinforced plastic injection molding parts,the problem of core wear in the injection moulding process of glass fiber reinforced PEI was explored.The micro wear morphology of core surface was observed by image tool microscope,the size of crescent groove was measured,and the type and cause of core wear were analyzed.The results show that the core wear is essentially the erosion process of glass fiber particles moving at high speed on core surface material.2.The physical model of mould surface erosion process is established,and the erosion process of mould surface is simulated.From the point of view of micro erosion,the deep reason of mould core erosion is studied.The results show that the incidence angle and dip angle of the glass fiber particles determine the erosion failure form of the core surface materials.The amount of wear increase with the increase of the roll angle of the glass fiber particle,which increase exponential type with the increase of impacting velocity.3.The filling and flowing process of glass fiber reinforced PEI melt was studied.The multi field distribution near the wall of cavity was analyzed.The erosion wear amount of the mould surface material was calculated,and the main influencing factors of the core erosion wear were determined.The results show that in the injection moulding process,the melt velocity near the wall of cavity determines the shape and size of the crescent wear groove,and the melt erosion velocity is the most important factor affecting the core erosion wear.4.Single factor numerical experiment was used to study the influence of injection moulding and mould structure parameters on the melt erosion velocity.Adjusting the injection process parameters can reduce the melt erosion velocity and alleviate the erosion of mould core.However,by adjusting the mould structure parameters,the melt erosion velocity can be greatly reduced and the formation of crescent wear groove can be avoided.The primary and secondary order of influence of mould structure parameters on melt erosion velocity is gate offset distance,gate size and gate angle.Combined with the restriction of the quality of the part on mould structure parameters,the optimum mould structure parameters for controlling the mould core erosion wear are obtained.