Induction Cap Sealing - Process
When it comes to package security, tamper evidence is a key requirement. While there are many methods for achieving tamper evidence, induction sealing continues to be one of the most popular. It forms a hermetic seal, which creates a protective barrier between the sealed product and the environment, and cannot be removed without leaving evidence of tampering. The seal also prevents leaks and, in most cases, can contribute to extending a product's shelf life. Unlike heat-sealing or pressure sealing, which do not provide tamper-evidence, induction seals work equally well with liquid and dry products.
An innerseal wafer [ WAD] is inserted into the cap of the container.

This is usually supplied by the cap manufacturer.

• Liner Construction

Here is shown a structural layout of the WAD
The container is filled and capped in a standard operation then passed beneath the sealing head.The electromagnetic waves generated by the sealing head penetrate through the cap to the aluminum foil layer as the container passes underneath. This is a non-contact process.
As the field penetrates the foil, due to eddy current losses it induces an electrical current flow that quickly generates heat. The temperature is then sufficient enough to activate the poly heat seal coating.