2-Piece Vs 3-Piece Cans: Choosing the Right Packaging

The two most popular can manufacturing processes dominate the industry. But which is right for your packaging needs?

Dating back to the 19th century, 3-piece cans are reliable and easy to produce. However, the more recently developed 2-piece can offer great benefits in terms of production and material consumption. So, which is the right choice when it comes to canning food and beverages?

The difference between 2-piece and 3-piece cans

A 3-piece can is created using a seamed body with an end and lid attached. A 2-piece can is produced by molding a piece of material into a body with an integral end, a seamed lid is then attached to close the can. Find out more about the manufacturing process in our guide to how beverage cans are made.

3-piece can pros and cons

Pros

• Good rigidity
• Easy to scale size
• Can be adapted to different can shapes
• Adaptable to a variety of different material types

Cons

• Side and top seams equal higher material consumption
• More potential weak points

2-piece can pros and cons

Pros

• Excellent sealing
• High production efficiency
• Low raw material consumption
• Straight-forward production

Cons

• More limited material options
• Need of specialized technologies, equipment, and dies

Where 2-piece and 3-piece cans perform best

2 piece cans dominate in the beverage industry, thanks to their excellent sealing properties and the fact the manufacturing process particularly suits lightweight aluminum and alloys. These materials have the added advantage of helping beverages cool quickly. The beverage industry is changing quickly. Find out more about the drive for innovation and quality control in the industry in our recent report, The Thirst for Perfection in Beverage Fillers.

One big benefit to 2 piece cans is that they have fewer seams, and therefore fewer potential weak points.

In food packaging, there is a more even split between 2- and 3-piece cans. The 3-piece design can offer various easy opening options and typically requires less advanced machinery to produce. 3 piece cans are also used for industrial packaging, thanks to the simplicity and versatility of the manufacturing process.

Testing and precision in can production

In particular, 2 piece cans require advanced technologies and precise measurements to create optimal packaging, but all can production lines benefit greatly from a good QA testing regime. Can inspection is a multi-layered system, allowing you to measure and test cans pre- and post-production, to ensure integrity.

While a specialized system is needed to fully test each can type, there are many pieces of testing equipment that are common to both, including double seam and implosion testing.

Testing for 2- and 3-piece cans from Industrial Physics

Find out more about the beverage can testing products we offer or give us a call to talk through your requirements. Our expertise encompasses 2-piece and 3-piece cans as well as alternative options. Reduce wastage, save time and create a testing solution you can rely on.

With 50 years of experience in the beverage and canning industry, we can help talk through your needs and find the testing solution to suit your production lines and process. Get in touch to speak with our team.

Torus Z702 Automatic 2 Piece Bottle Can Inspection Gauge in action

The importance of can inspection

It may sound like a bold statement – but the humble metal can is one of the greatest inventions of the last 200 years. 

There have always been lots of contenders to the metal packaging throne – from bottles to drums – but now the 2-piece aluminum can reigns supreme. And the tin-coated 3-piece steel sibling remains a tried and tested favorite too!

As the world moves towards a circular economy; as the perils of plastic pollution focus on the consumer’s mind; many companies are making the move to metal. Which means they need to invest in metal can inspection.

Both the 3- and the 2-piece aluminum can have become integral in the success of many different industries. Cans are used by companies working in everything from food and drink to the paint and automotive sectors. They have helped millions of people to eat fresher produce and millions of companies to transport their products safely…all over the world. Cans come in all shapes and sizes, while can inspection comes in many forms.

Sounds good right? Yes, but before you switch up your packaging from plastic to metal, ahead of investing in inspection equipment for packaging lines, there are a few can inspection considerations. Here are three for starters…

Double-seam dilemmas: fail to use the right can testing equipment to properly check the hermetic seals of your cans, you’ll end up with seam defects. A defective batch – or even just a single can – is all it takes to put a big dent in your reputation and finances. Fortunately, there are full can inspection and empty can inspection solutions to check your seams are solid and your cans are leak-free.  

Transportation troubles: how will your cans respond when dropped from a height, crushed or compressed? Dented can inspection can help here. Will your cans encounter temperature fluctuation when being shipped or on the road? With ‘real world’ can inspection you can check if your products will expand or form vapor in their containers. Which could lead to a misshapen final product, or even corrosion.

Shelf-life scrutiny: you’ll need to know metal packaging will impact the shelf life of your products. Will you have to change your use and sell-by dates? With the right can testing equipment you’ll get the answers. There are also abrasion considerations  – does the metal you have chosen work with the paints and labels you use? Will your metal cans still look good after weeks, or months, of rubbing together?

Can inspection in relation to sustainability demands

Aluminum and steel cans have slimmed down a lot in recent decades, disrupting the process of can inspection.

Across Europe, the weight of 3-piece steel and 2-piece aluminum cans has been reduced by one-third over the last 25 years. Obviously, there are massive cost-cutting implications of using less material to consider. But as technology advanced, the aesthetic appeal became more important and began to play a key factor. This created a need for new metal can testing equipment.

These days the main driver has shifted to one of ecological concern and sustainability.  Lightweight cans use less material and produce less CO2 emissions – ultimately resulting in an eco-friendlier package.

Whenever you make big changes to any type of packaging – especially when you take the material away – there are quality implications to consider. And can inspection considerations. Yes, you save a lot of money by stripping back on raw materials…but there are additional costs you may not have thought of.

Alter the tried and tested way things are done and you challenge your manufacturing processes, often stretching the capabilities of your metals. So when you strip things back, your R&D functions must allow for this. You must make sure your can inspection quality control is fit for purpose – both your empty and full can inspection procedures become all the more important.

We’ve been doing this for over 50 years – give us a chance and we’ll talk about can inspection all day! We hope that you find this FAQ guide to can inspection helpful. If you have more questions for our technical teams then get in contact today.

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