Prevention of defects in injection molding process in the manufacturing of ballpoint pen

Abstract

Injection molding is one of the major manufacturing processes for thermoplastic polymers. In injection molding machine, process variables play a very important role in generating defects in products. In the present paper manufacturing of ball point pen is taken up to investigate the prevention of defects through design and controlling various process parameters. Two molds are designed and fabricated specially for this experimental work. The analysis showed that the defect occurrence has close relation with pressure, speed and the temperature of the injection molding machine in addition to the basic design of the mold. The paper suggests preventive actions for the defects like flash, burn marks, short shot, shrinkage, weld line, warpage and sink mark. The preventive actions were successfully implemented in manufacturing the ball point pen.