Design of an Efficient Induction Heating CoilFor Barrel Heating System of an Injection Molding Machine

• Main Authors: Huy-TienBui, 裴輝進
• Other Authors: Sheng-Jye Hwang
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/23306997745694741754

博士 === 國立成功大學 === 機械工程學系 === 102 === In an injection molding machine, the conventional barrel heating system which uses resistance heating method (RH), has some drawbacks such as low heating rate, long heating time, and energy loss. With induction heating (IH) technique, the barrel can better almost all of these disadvantages. However, non-uniform temperature distribution on inside surface of a barrel is the main drawback of induction heaters. In this thesis, a barrel heating system was developed using induction heating instead of resistance heating. And, to design a induction coil for the induction heating system so that the barrel has uniform temperature distribution. Firstly, methods of adjusting the pitch of turns of working coil and adding magnetic flux concentrators would be developed. Secondly, a working coil coupled with magnetic flux concentrators via adjustment of magnetic flux concentrator spacing to achieve uniformity of magnetic flux and temperature distribution on the inside surface of a barrel was proposed and experimented. Finally, Different pitches of magnetic flux concentrators were applied to study the uniform heating capability of induction heating system with heating coil coupled with magnetic flux concentrators via commercial software, ANSYS. In addition, changing diameters of a barrel and varying operation frequency of induction power supply were investigated to effects o uniform temperature distribution at the inside surface of the barrel. Results showed that, when barrel was heated by induction heating method with the proposed induction heating coil, heating time to reach a specific temperature could be reduced, and heating rate increased compared to resistance heating method. With 8 mm pitch of magnetic flux concentrators on a coil, the temperature distribution was the most uniform. The results from simulation and experiment agreed well. Simulation results showed that, changing diameters of a barrel or varying operation frequency of induction power supply had no effect on uniform temperature distribution at the inside surface of the barrel. 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.