Things to Keep in Mind When Designing an Induction Heating Coil
Induction heating coil design plays a role in the effectiveness of the induction heating process. As a result, it is crucial to make the best selection when choosing its components.
The tubing of the coil must have high-conductive copper. The copper tube with an outer diameter of at least 0.32 cm ensures easy water cooling.
Nevertheless, the diameter could be as large as 5.1 cm for applications that need high power.
Coil Turn Numbers
Multi-Turn coils are ideal for single-shot, large-diameter heating. These coils have multiple turns that increase the overall proportion of the coil. However, when the diameter of the coil exceeds 4x–8x, it becomes difficult to produce uniform heating.
Single-turn coils are suitable for heating bands with narrow diameters. The height and diameter of single-turn coils vary slightly with size.
Design of Coil Leads
The design and structure of the work-coil lead have the main influence on the performance of the coil.
The coil has a tank circuit. All the leads connecting the tank capacitor to the coil have inductance. When the coil heating area has a higher inductance, it counterbalances the effect of lead inductance.
Coil bracing is another crucial factor to consider when designing an induction coil. Coil bracing stops the magnetomotive force from making unwanted movements.
When electric current flows in the coil and workpiece, it generates magneto motive forces. The force can become uncontrollable during induction heating. Therefore, braces are crucial.
Distance of Coupling
Coupling is the term used for the gap between the induction coil and the workpiece.
For progressive heating, the coupling distance should be 0.19 cm.
However, if the workpiece is a magnetic material, the coupling distance should range from 0.25 to 0.38 inches.
The small gap between the coil and the workpiece is known as tight coupling, while the large gap is called loose coupling.
Most manufacturers anneal the coil tubing every few bends. It prevents the deformation of the coil.
The tubing is heated until it becomes bright red. After that, it is cooled rapidly with water. The process prevents the coil from fracturing during fabrication.