Preliminary Study On The Fiber Breakage And Distribution Of The Long Glass Fiber Reinforced Polypropylene Injection Molding

With the rapid development of socio-economic, long fiber reinforced thermo-plastics are widely used in the national economy due to their excellent perform-ances.Take the automobile industry as an example, according to statistics, the total output of cars in our country was more than19million units in2012, up4.6%year on year, predicting the production volume will have achieved21million units and will have shared the thirty percent of the global car production by2015. So lightweight of automobile is very important as one of the effective ways for energy-saving and emis-sions-reducing in our country. Long-glass fiber reinforced polypropylene (LFR-PP) has some advantages, such as light mass, high strength, easy molding and low cost. LFR-PP is becoming a substitute for engineering plastics and metal material. In this context, this article studied the micro-appearance and mechanical properties of the LFR-PP during the molding process.(1) A device for mensuring long fiber length in LFR-PP was set up. The ertaction platform of the long glass fiber length was set up by the circulating water vacuum pump, conical flask, funnel, homemade filter paper, beakers and other devices. Long fiber length in LFR-PP under different experimental conditions was measured and counted by the stereoscopic microscope, and the fiber breakage effects on mechanical properties were also discussed.(2) Fiber distribution in the injection molding LFR-PP standard samples was observed. The injection molding LFR-PP standard samples were grinded by160,200,400,200,800,1000,1200sandpaper and polishing machine. The thickness of the surface layer, the shear layer and core layer was calculated by metallographic micro-scope. The reunion behavior of the fiber was observed and the influence of fiber dis-tribution on mechanical properties was discussed.(3) The numerical simulation for LFR-PP injection molding process was done by Moldflow2013, and then the simulative results were compared with the experimental results. On the basis of further validating the experiment results, this paper proposed some improvement measures for the analysis model in numerical simulation software. (4) In this paper, the forming process of the LFR-PP weld line by the flat speci-men with square hole was discussed, the micro-appearance of weld line was observed, and the mechanism of formation of the weld line was analyzed. At the same time, the forming process of the weld line in LFR-PP injection molding was simulated by Moldflow2013.