A novel technique for in-situ manufacturing of functionally graded materials based polymer composite spur gears

The authors propose a different manufacturing process developed to fabricate functionally graded material (FGM) based thermoplastic gear. FGM and homogeneous gears are manufactured by means of an especially designed mould and a punch. The punch acts as an integral rotating member of the mould and has a cavity carved in the shape of gear where the material is filled to produce gears. The punch rotates at 1,800 rpm for 2 min to force at segregation of fibers towards the periphery of the punch cavity because of the centrifugal force in action. Polypropylene (PP) filled with 15 and 30 wt% glass fibers is used to fabricate FGM and homogeneous gears. Unfilled PP gear is also fabricated for comparative study. Gradation in FGM gear is verified by Scanning electron microscope (SEM) analysis and Shore D hardness measured in three different locations of the fabricated FGM gears. Gradation in FGM gear is also verified by ignition loss test method. Continuous gradation is observed in FGM gear by SEM and confirmed by hardness test and ignition loss test. In this work, transmission efficiency of unfilled, homogeneous and FGM PP gears during operation is also investigated and compared. A polymer gear test rig is used for experimental work. This route shows a promising potential for fabrication of FGM based thermoplastics gears which otherwise is difficult to manufacture because of their fast solidification properties at room temperature. POLYM. COMPOS., 40:523-535, 2019. (c) 2017 Society of Plastics Engineers