10 factors to consider when choosing an induction heating system

Introduction to Induction Heating

Induction heating offers many benefits for manufacturing processes, as it is a fast, energy-efficient, and flame-free method of heating electrically conductive materials. A typical system consists of an induction power supply, a workhead with a copper coil, and a chiller or cooling system. Current flows through the coil creating a changing electromagnetic field. When the conductive part is placed inside the coil, eddy currents are generated within it. The flow of eddy currents combined with the resistive properties of the conductive part generates heat within it.

Key Factors in Choosing an Induction Heating System

It is crucial to select the right system for a given application and its requirements. A system with too much power might lead to unnecessary expenditure, while a system with too little power could prolong the heating process and slow down production. We present 10 factors to consider when choosing an induction heating system.

1. Material of the Workpiece

Induction directly heats conductive materials such as metals. Non-conductive materials are sometimes heated using a conductive susceptor. Due to hysteresis, magnetic materials heat more easily than non-magnetic materials. Consequently, non-magnetic materials often require more power. Metals with high resistivity, such as steel, heat up quickly, while metals with low resistivity, such as copper or aluminum, require more time to heat.

2. Depth of Thermal Penetration

The induced current will be most intense at the surface of the part. In reality, over 80% of the heat generated in the part is produced near the surface. Therefore, larger parts and parts requiring through-heating need more time to heat up compared to thinner or smaller parts.

3. Operating Frequency

Systems with lower frequencies and higher power are suitable for heating larger elements that require through-heating. Systems with lower power and higher frequency are often the right choice for surface heating. The general rule is that the higher the frequency, the shallower the heating of the part.

4. Applied Power

The output power of the induction heating power supply determines the relative speed at which the part is heated. Considerations include the part's mass, temperature rise, and heat losses due to convection and conduction. Often, the induction equipment manufacturer can assist in making this assessment.

5. Temperature Rise Requirements

Induction can generate significant temperature changes, but generally, to accommodate these changes, higher power is needed, which will affect the choice of power supply. The rate of temperature changes can also impact the choice of such a power supply. The faster the rate of change, the higher the power requirement.

6. Coil Design

The coil, which is usually water-cooled and made of copper, must be tailored to the shape of the part and consider process variables. An optimal coil design will deliver the proper heat distribution to the part efficiently. A poorly designed coil will heat the part more slowly and less effectively. Flexible coils are now available and work well for large and uniquely shaped parts.

7. Coupling Efficiency

Coupling the part with the coil increases current flow, which simultaneously increases the amount of heat generated in the part. Coupling allows for faster and more efficient heating, which can enhance production efficiency. Poor coupling has the opposite effect.

8. Work Area and Setup

The induction heating setup requires cooling via a cooling unit or cooling system. Lower-power systems typically require a compact water-to-air heat exchanger, while higher-power systems may need a larger water-to-water heat exchanger or chiller. Additionally, space is needed for the induction power supply and workhead. Generally, an induction system will save a significant amount of space compared to a furnace, especially considering that the workhead can be placed at a considerable distance from the power supply. Of course, it is also important to ensure that the facility can handle the amount of energy the system requires.

9. Additional Requirements for Induction Heating Process

Will there be a need to measure and store heating data? Some induction solution providers may offer a complete system that includes an optical pyrometer and temperature monitoring software, allowing such data to be recorded and stored. A comprehensive solution can lead to a seamless installation and commissioning.

10. Industry Experience

Many induction equipment manufacturers have experience with specific applications, and if they have worked with your application, it provides peace of mind. Additionally, some suppliers offer laboratory tests and system recommendations tailored to customer needs based on their heating requirements. These services help avoid guesswork in selecting the system and assist in considering the factors mentioned above.

Summary

In summary, induction heating has many advantages compared to other popular heating methods. Purchasing the right system for a given application and ensuring it meets any future needs will help your company fully benefit from its advantages.

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