What Induction Sealing Can Tell Us About Innovation in Manufacturing

Plastic and foil seals are a vital part of keeping essential goods fresh, from milk to medicines. For the last 35 years, manufacturers have fixed these lids on with induction sealing: the process of bonding thermoplastic/foil laminate materials through induction heating. Historically, this process has been limited to induction cap sealing: relying on a screwcap to keep the lid in place while using electromagnetic induction to heat an electrically conductive foil from a distance, through the plastic. This in turn melts the polymer resin in the lid onto the neck of the container to form a hermetic seal. It’s incredibly effective for containers with screw caps, as the cap holds the lid in place with the right amount of pressure for it to bond to the container neck.

This approach to induction sealing was “good enough” for many years. The fact that it worked perfectly well at it’s designated task meant that improvement was not particularly sought after or requested. But as with any technology that stagnates, this lack of innovation began to show its weaknesses and holding the industry back.  

Many containers that require hermetic seals do not or cannot accommodate screwcaps – square containers are one example. And rigid materials, such as glass, do not offer an even contact surface, making them difficult to hermetically seal with a cap alone. Most importantly here, many applications in life sciences require a simple, hermetically sealed lid that can be easily punctured, or torn off by someone wearing gloves – so any kind of screwcap is unsatisfactory.

Over time, these limitations became more pressing – particularly as consumers began demanding more easily transportable products in lighter packaging and different shapes. At Relco we realised there needed to be a more efficient and versatile option that didn’t require screw caps, without sacrificing the productivity of this tried-and-tested technology.

The catalysts for innovation

The need to go beyond what traditional induction sealing methods could offer might sound like a problem. But these kinds of drivers are essential to move innovation forward – in any industry. The demand for greater productivity, sustainability and efficiency often lead to new ideas and different ways of approaching new problems – which, in turn, can have new, unforeseen applications further down the line. Nowhere is this more vital than in manufacturing, where customer demands are devoloping at unprecedented pace, there is a growing need for flexibility and sophistication in assembly lines and supply chains.

Let’s look back at the induction cap sealing issue. Seeing the growing need in many industries for hermetically sealing without a screw cap, we decided to try something new. So we began working on a solution that autonomously positions lids with the correct amount of pressure, without the need for a screw cap, and developed our direct contact induction sealing solution.

Our partners can use this technology to seal all kinds of containers, without the need for screwcaps or a completely even contact surface. This isn’t a trivial advantage. It allows businesses and manufacturers to rapidly protect perishable or spillable products, with a soft peelable lid that can be quickly and easily removed by hand, without the need for any great dexterity. The direct heating solution can melt a foil seal in 200 miliseconds, enabling faster sealing times for much quicker throughput. The solution is also more sustainable; the heating element for direct induction sealing remains at ambient temperature, saving power, while reducing wear and tear, and the risk of accidents.

This is particularly vital when producing diagnostic tests, where moisture- or oxygen-sensitive chemicals and re-agents need to be transported in small, measured doses that are easy to open. Over the years, since developing our direct-induction sealing solutions, many of our clients in life sciences have begun to rely heavily on our ability to seal and protect these vulnerable materials.