Shrink Fitting a Magnetic Steel Gear

Objective

To heat a magnetic steel gear for a shrink fitting application; they’re looking to replace an oven that takes over two hours to heat the part to temperature

End Product

gear

Equipment

Ambrell EASYHEAT^TM 2.4 kW, 150-400 kHz solid state induction power supply with a workhead and coil specifically designed for this application

Materials

Magnetic steel gear, 2” (55 mm) ID, 12.5” (318 mm) OD

Temperature

550 °F (288 °C)

Frequency

180 kHz

Testing

A custom-designed single position multiple-turn pancake coil was built to generate the required heating for this shrink fitting application. Initial tests were conducted to optimize the power delivered to the part. Temperature indicating paint was then applied to the part, which dissolves when the part reaches the target temperature. 

It was observed that it took 45 minutes to heat the sample to temperature. The coil can be placed beneath the gear to allow oil to burn off without condensing on the coil.

Benefits

• Speed: Induction cut the client’s heating time in more than half when compared to their oven. 

• Footprint: Induction requires less space on the factory floor than an oven.

• Efficiency: Induction only heats what needs to be heated, so it tends to be more efficient than an oven

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