Induction Coil Design & Frequency Selection for Heating Applications

Induction coil design has a major impact on process efficiency and final part quality, and the best coil design for your product largely depends on your application. Certain coil designs tend to work best with specific applications, and a less than optimal coil-application pairing can result in slow or irregular heating, higher defect rates, and lower quality products.

First, consider these three factors

Part motion relative to coil

Several applications rely on part movement with the help of conveyors, turntables, or robots. A properly designed induction coil incorporates these individual handling requirements without the loss of heating efficiency.

Frequency

Higher frequencies are used for applications like brazing, soldering, annealing or heat treating, where surface heating is desired. Lower frequencies are preferred for applications requiring through-heating of the parts to the core like forging and die heating.

Powder-density requirements

Higher power densities are required for short cycle heating applications requiring high temperatures. Higher power densities may also be required to keep the hot zone confined to a small area, reducing the heat affected area.

different applications, Different coils

Annealing

• Simple solenoid coils (single- & multi-turn)
• Multiple position helical coils
• Pancake coils, transverse flux coils
• Channel coils
• High frequency

Bonding

• Simple solenoid coils (single- & multi-turn)
• Multiple position helical coils
• Pancake coils, transverse flux coils
• High frequency

Brazing

• Simple solenoid coils (single- & multi-turn)
• Contoured coils to match the shape of the part being heated
• Channel coils
• High Frequency

Curing

• Simple solenoid coils (single- & multi-turn)
• Multiple position helical coils
• Pancake coils, transverse flux coils
• Medium frequency

Forging

• Simple solenoid coils (single- & multi-turn)
• Multiple position helical coils
• Low frequency

Hardening

• Simple solenoid coils (single- & multi-turn)
• Multiple position helical coils
• Low frequency

Heat treating

• Simple solenoid coils (single- & multi-turn)
• High frequency

Melting

• Multi turn helical coils, heaving parallel water and electric paths
• Low frequency

Progressive hardening

• Simple solenoid coils (single- & multi-turn)
• Low frequency

Shrink fitting

• Pancake coils, transverse flux coils
• Channel coils
• Medium frequency

Soldering

• Simple solenoid coils (single- & multi-turn)
• Contoured coils to match the shape of the part being heated
• Channel coils
• High Frequency

Tempering

• Simple solenoid coils (single- & multi-turn)
• Multiple position helical coils
• Internal bore coils for internal diameter heating
• Channel coils
• Low frequency

Designing a coil for your application

Start with understanding where the heat needs to be generated in the part to perform the process, and then design the coil to achieve the heating effect. Similarly, frequency selection will depend on the induction heating application you’ll be using for your part.

Want to learn more? If you’d like to get an experienced set of eyes on your induction application, our team is available for consultation.

Contact us for help with your coil design needs!