Induction sealing is a process that bonds thermoplastic materials using induction heating. An induction sealing machine generates controlled heat through an electromagnetic field, which interacts with an electrically conductive object (such as aluminum induction sealing foil). The eddy currents in the object generate heat, melting the connected thermoplastic materials together.

Induction sealing is crucial in product packaging to ensure the package preserves its contents, remaining airtight and preventing contaminants from entering.

There are many types of manufacturing applications for induction sealing. In packaging, induction sealing equipment can be used to attach plastic closures to packaging or to create forming tubes using flexible materials. Cap sealing is one of the most common applications of induction sealing. The method is a non-contact induction sealing process that seals the top of a glass or plastic container. Once the container is filled and capped, an induction cap sealing machine heats an inner seal to create a hermetic seal.

A Brief History of the Induction Sealing Process

In 1957, scientist Jack Palmer first conceived the concept of induction sealing. His original goal was to prevent polyethylene bottles from leaking during shipping. In 1960, his induction sealing technology was recognized by the U.S. Patent, and from there the technology spread across the world.

Over the years, several advancements, including the advent of high-tech induction sealing machines, significantly improved induction sealing methods. In 2004, manufacturers introduced a 6 kW induction sealing machine with better capabilities than ever before, marking a significant milestone in the packaging industry.

How Does Induction Sealing Work?

Bottlers receive closures with a pre-inserted aluminum induction sealing foil liner. Most induction liners have multiple layers, but there are various options available. The top layer is usually a paper pulp backing. The layer below it is wax, which bonds the aluminum foil layer to the paper pulp. The bottom layer is a polymer film that is laminated to the foil. Once the closure is applied, the bottle undergoes the following induction sealing process:

  1. The container passes through an induction coil or sealing head, and the aluminum foil liner starts to heat.
  2. The high induction sealing temperature melts the wax, which absorbs into the paper pulp backing. This releases the aluminum foil from the closure.
  3. The polymer film heats and flows around the lip of the bottle.
  4. The cap is cooled, which allows the polymer film to bond with the container in a hermetic seal. Neither the bottle nor its contents are adversely affected by heat or any other aspect of the sealing process.

Commonly referred to as cap sealing, the entire induction sealing process is fast and efficient. Product containers with a cap and foil liner and raw materials are passed through the induction sealing equipment, transferring energy through a controlled magnetic field.

How Does an Induction Sealing Machine Work?

The induction sealing process requires applying induction current to a metal liner placed inside a plastic cap. After a bottle gets filled with the necessary contents, the machine attaches the cap, which contains the liner with the appropriate sealing material adhered to a foil layer. The induction current creates heat that melts the polymer sealant around the threaded bottle cap. The cap provides the necessary pressure for the induction sealing equipment to tighten the closure. The sealing layer adheres to the bottle after it cools. Induction sealers offer tight, reliable seals.

Induction sealing can be performed by large, efficient machines and adaptable, handheld sealers. Depending on the size and scale of your application, there is a variety of induction sealing equipment to choose from.

Many industries rely on induction sealing for plastic bottle packaging:

  • Pharmaceutical
  • Medical
  • Food and beverage
  • Automotive
  • Aerospace
  • Electromechanical assembly
  • Hardware manufacturing
  • Life sciences

Captech Automation, LLC has experience assisting companies in a variety of markets with their unique sealing challenges. Regardless of the company’s size, our induction sealing equipment is energy-efficient and highly functional, providing the seal integrity your application demands every time.

Technologies Involved in Induction Sealing

Induction sealing machines vary in operation, size, and design. With such a broad range of options available, there are many different segments and components to consider. While all parts of the induction sealer are important, the main considerations for bottlers are sealing efficacy and power consumption.

The two main components of an induction cap sealing machine are the sealing head and the main power supply. Other parts include:

  • Control panel
  • Generators
  • Inductive unit
  • PLC
  • Pneumatics
  • Reel holders

Benefits of Induction Sealing

Businesses elect to use induction sealing for a variety of reasons, such as:

  • Freshness retention
  • High-speed production
  • Leak prevention
  • Protection against pilferage
  • Sustainability
  • Tamper evidence

Cap Lining Machines From Captech Automation

Captech Automation, LLC offers high-quality cap lining systems for operations of any size. Our state-of-the-art closure lining machines allow us to produce higher-quality products and larger production yields in the most cost-effective manner.

Choosing the proper closure lining machine system for your cap type and material is essential to reap all the benefits of induction sealing technology. Captech Automation can customize our cap lining equipment to fit your company’s specific inspection, assembly, orienting, and testing needs.

We design and manufacture indexing star-wheel type, rotary die type, and shuttle-type cap-lining machines. Our machines provide numerous benefits and functions, which include:

  • Authentication of product integrity
  • Contamination prevention
  • Enhanced consumer confidence
  • Graphic communication and promotion
  • Leakage prevention
  • Preserved freshness

Contact us today to learn more about our closure lining machines. You can also request a quote for specific pricing information.