What is the comparison of heating efficiency between infrared heating and electromagnetic induction heating in hot runner systems?

The heating efficiency of infrared heating and electromagnetic induction heating in hot runner systems is affected by many factors. The following is a comparative analysis of the two:
Theoretical heating efficiency
Infrared heating: Infrared heating relies on infrared radiation to transfer energy. The object absorbs infrared radiation energy and converts it into heat energy. However, in actual applications, some infrared radiation will be reflected or absorbed by the surrounding environment and not fully utilized by the heated object. Its theoretical thermal efficiency is usually around 60% - 70%.
Electromagnetic induction heating: Electromagnetic induction heating uses an alternating magnetic field to generate an induced current inside a metal object, thereby generating heat. This heating method directly generates heat inside the heated object, with little heat loss and a thermal efficiency of more than 90%.
Actual heating efficiency in different scenarios
Heating of small-sized, thin-walled objects: For small-sized, thin-walled objects, infrared heating can quickly heat up the surface of the object, and the heat can be quickly transferred to the entire object. In this case, the efficiency of infrared heating is high and can be close to its theoretical efficiency. For example, when locally heating some small plastic parts, infrared heating can reach the required temperature in a short time. Although electromagnetic induction heating is highly efficient, it may not be able to fully exert its advantages for small objects due to the limited heat generated by the induced current, and the equipment debugging is relatively complicated. In this case, infrared heating efficiency may be more advantageous.
Heating of large-sized and thick-walled objects: For large-sized and thick-walled objects, infrared heating can only heat the surface of the object due to its limited penetration ability, and then rely on heat conduction to heat up the inside, with slow heating speed and low efficiency. For example, for the heating of large injection molds, infrared heating takes a long time to make the inside of the mold reach a uniform temperature. Electromagnetic induction heating can generate heat inside the object, with fast heating speed and high energy utilization rate. The heating efficiency for large-sized and thick-walled objects is significantly higher than that of infrared heating.
Scenarios requiring rapid heating: In scenarios where rapid heating is required, such as the heat sealing process of food packaging, infrared heating can use its characteristics of rapid emission of infrared radiation to quickly increase the temperature of the heated part to meet the requirements of rapid heat sealing. At this time, the efficiency of infrared heating is better. However, electromagnetic induction heating can also achieve rapid heating by adjusting electromagnetic parameters, and can maintain high efficiency during continuous heating. Therefore, both have their advantages in rapid heating scenarios, but electromagnetic induction heating has greater potential in long-term rapid heating.
High-precision temperature control scenarios: In scenarios with high requirements for temperature control accuracy, electromagnetic induction heating can accurately control the temperature near the set value with its precise temperature control ability, reduce energy waste caused by temperature fluctuations, and thus improve heating efficiency. However, infrared heating may have too high or too low temperatures due to relatively inaccurate temperature control, resulting in prolonged heating time or energy waste. In high-precision temperature control scenarios, electromagnetic induction heating is more efficient.