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An article of footwear may be constructed with a foam sole portion (54). The formation of the foam portion may involve heating the foam portion utilizing one or more heating elements. However, a traditional heating element, such as an oven, used to heat and cure a foam item is continuously energized to maintain sufficient thermal energy and may be inefficient at heating the foam item. Furthermore, the ability to control the heating and timing of the foam item may be limited with a traditional heating element.

An induction heating assembly has been used to cure an expanded foam structure (54). Modular induction heating assemblies can efficiently and controllably heat a mold that contains a foam item. In order to achieve efficiencies and controllability, inactive zones and cooling mechanisms were used in connection with induction heating assemblies to regulate the temperature of the mold during the curing process. Figure 1.4 shows an induction heating assembly that is configured to house induction coils and a mold.

Figure 1.4 Induction heating assembly (54).

The induction heating assembly may house coils having a combination of coil patterns. Chamber rollers may allow a belt, such as a conveyor belt, to pass over the chamber rollers and through the cavity of the inner chamber. Also, the chamber rollers may allow a foam item to pass through the cavity so that it may be cured utilizing the induction coils (54).

Various induction heating assemblies and soaking zones may be used. For instance, four induction heating assemblies and four soaking zones may be used where each soaking zone is between each induction heating assembly. Similarly, it is contemplated that a dwell time within a soaking zone or as influenced by an induction heating assembly may be adjusted to achieve a desired intermediate temperature.

For example, on a moving conveyor having a constant speed, the dwell time may be changed in the soaking zone by changing a length between induction heating assemblies. The rate of the conveyor belt movement may also be manipulated to change a dwell time in the soaking zone — and exposure to induction heating effects within the induction heating assemblies.