In today’s scenario, mostly everywhere especially automotive industries prefer to use lightweight materials to increase the efficiency of their vehicle. Fiber Reinforced thermoplastics (FRT) are the commonly used materials for this scenario as they are easily available, cheaper, lighter than metals, non-corrosive and also satisfactorily efficient etc.. For injection molded parts, glass and carbon fibers are the commonly used ones to enhance their mechanical and thermal properties. The orientation of fibers in the parts plays a vital role in making the mechanical properties better. In this work, the product is Polypropylene (PP) reinforced with 50% and 40% weightage of long glass fibers that are manufactured using an injection-molding machine. The glass fibers have an average length of 25 mm and average diameter of 17 µm are reinforced with polypropylene in the form of pellets and are used in the injection-molding machine to form the product. The product is undergone mechanical testing and brought it for experimenting that includes manual polishing and scanning technique using an optical microscope. This technique is implemented to observe the flow pattern of the fibers in the composite. The sample cut out of the product from the double gate section is then put inside the PMMA, polished and scanned in the cross-sectional direction to see the flow of fibers in the composite. Using grinding and polishing papers, the sample is polished using a grinder-polisher. The polished samples are scanned under an optical microscope and the microscope is operated using a software, ‘pylon viewer’. The scanned images show the fibers’ flow layer by layer throughout the part. Defects like- fiber bundles, voids and weld lines in the samples are discovered during the work. The flow phenomenon of fibers is observed in all the layers and there is no layered structure and the fibers are randomly oriented in-plane. The flow phenomenon is more likely to be plug flow.

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