Spherulites formation sometimes affects melt flow during micro-injection molding. During mold filling solidification and crystallization occur at the same time. As a result, unusual flow front can be shown in the molded parts. With a simple cavity with periodic channels, repeatedly created spherical structures are formed in the molded part. It is found that such structures are formed due to spherulites. However, this work also has found that in an alternative process with slow filling speed, such structure was never observed. It is postulated that onset of this phenomena is related to both spherulite size and relaxation time inside spherulites based on the experimental clues.