Development of barrel heating system in injection molding machine via induction heating

Abstract

Purpose– The purpose of this paper is to develop a barrel heating system using induction heating instead of resistance heating. And, a working coil for the induction heating system was designed so that the barrel has uniform temperature distribution.Design/methodology/approach– A coupling design combining the pitch of turns of working coil with the magnetic flux concentrators in the barrel induction heating system was developed to achieve uniform temperature distribution which was approximately the same as temperature uniformity obtained from that of resistance heating system.Findings– In contrast to resistance heating method, induction heating is more efficient because the heating is directly applied on the work-piece. Its heating rate is higher than that of resistance heating method. However, the uneven temperature distribution in the barrel is the main disadvantage of the induction heating system. But, with proper design of adjusting the pitch of turns at the center of working coil and adding magnetic flux concentrators at areas with lower magnetic flux, the barrel heating system via induction can achieve temperature distribution uniformity.Originality/value– Under proper design of working coil, the barrel heating system by induction method can achieve the same uniform temperature distribution as the barrel heated by resistance method, and could be practically used in an injection molding machine.