Study On Electromagnetic Induction Heating Temperature Mathematical Model And Numerical Simulation Of Barrel Of Injection Molding Machine

This paper mainly does research for the numerical simulation of temperature distribution of barrel of injection molding machine in electromagnetic induction heating. The electromagnetic induction heating process generates heat by means of Joule effect resulting from an eddy current, it is widely used in industrial operations due to its fast temperature rising, high efficiency, precise control, low pollution and low thermal inertial properties. It is an important problem to control each parameters of the electromagnetic induction heating system to ensure that every properties of barrel are reasonable. In fact, some properties are linked to temperature distribution in heat treatment process. However, the design of an electromagnetic induction heating system based on experiments would be tedious and time-consuming. Therefore, numerical simulation seems a well-adapted tool for the design and the investigation of induction heating system.In this paper, by applying the basic principle of electromagnetic induction heating and Finite Element Method of Electromagnetic-Thermal Coupled Field, and based on the Electromagnetics theory and Thermal theory, the mathematic analysis models of electromagnetic field and temperature field were constructed. Through the introduction of magnetic vector potential, the mathematical model of electromagnetic field and eddy current field was established.The coupled thermal and electromagnetic field problem taking account of nonlinear materials characteristics related to temperature was discussed. The induction heating process of barrel was analyzed, and the temperature distribution and its variation with time were obtained. The effect of induction heating including the variation of frequency of the inductor, current intensity coefficient of the coil on temperature control was analyzed. Through the results, the process and characteristics of the rising of induction heating temperature can be understood, which provides the basis of barrel temperature control of injection molding machine and is helpful to select the parameters of the induction heater.For the electromagnetic induction heating barrel, using its high efficiency and different heat generation principles, the barrel compared with the resistance heating barrel whose power is allocated by surface area can be optimized in the structure, barrel wall thickness can be thinned to save material.A new temperature control method called isochronal temperature control method is designed for preheating barrel of injection molding machine to reach different temperatures at the same time. Based on the original temperature control system, the method applies late startups in preheating. With the new method, at the preheating stage of the injection molding machine, all heating sections of the barrel can reach their corresponding set temperature values at the same time. Each section's heating delay-time is compared with its previous delay-time and saved for its next startup, and will become more accurate in the future startups. So the adaptive control of delay time is achieved. Practice proves that the new temperature control method can avoid the loss of heat energy owing to the low set temperature sections' waiting for the high set temperature section to reach its set temperature, reduce the unnecessary energy waste in the temperature control device, and achieve the energy-saving purposes.