Double seaming process guide
An effective double seam is crucial to the integrity of cans. Across the beverage industry, and food sector, this is a widely used process designed to create a hermetic seal during canning. Read on for a quickfire guide to the double seaming process.
Understanding the double seam
A double seam is a canning process that creates a seal between the can body and lid (also known as can end). It does this by mechanically interlocking five layers of material together – three layers of the can lid and two layers of the can body. This process creates a hermetic seal to keep the contents protected from contamination or degradation.
The combination of materials used to make a can have expanded massively since the double seam was first introduced. From traditional tin or steel to aluminum or plastic, there are a huge variety of ways to double seam a can.
The double seaming process
Not all double seams are the same, but they are all created using a double seaming machine capable of curling the flange (or edge) of the can body down over the lid to create an interlocked seam. Find a quick guide to terminology in our double seam glossary.
This is achieved with a double seaming machine and while the machines themselves vary, there are three main stages to the seaming process.
- Compression – the body of the can is tightly held in place while the lid is lowered into the correct position, ready for interlocking to take place
- 1st roller operation – the lid is hooked over the edge of the can and a roller pushes against the lid’s flange until it folds neatly round the body’s edge
- 2nd roller operation – a second roller applies pressurized force to the can’s hook, creating a double seam that is completely interlocked and hermetically sealed
Find everything you need to know about double seaming and testing in one handy place by downloading our seam inspection guidebook.
The history of the double seam
The invention of double seams in 1888, by Max Ams, eliminated the need for solder in the canning process. With roots in the era of industrialization, the double seam is almost as old as the canning process itself. New processes and techniques have ensured it remains the method of choice for sealing cans right up to the modern day.
Double seams today
Double seaming remains a simple, proven, and reliable way to provide a hermetic seal – it is used throughout the food and beverage packaging industry. Successful double seaming requires: a set up that conforms to industry specifications, exact seam measurements, and various quality assurances.
To ensure all of those, rigorous seam inspection is essential. Just a small variation in the seaming process can cause irregularities that compromise the hermetic seal. Find out more about how to measure a double seam or discover a handy toolkit for your seaming process with the Industrial Physics SEAM Doctor system.
Help with your double seam testing
A strong and hermetic double seam relies on good equipment, thorough measurement, and a comprehensive testing system. With 50 years of experience in the beverage and canning industry, we have the expertise to help.
If you’d like to find out more about the testing solutions and 3000+ unique products we have available, from double seam inspection to beverage testing solutions, get in touch to speak with our team.