Foam conversion – what is it, and how it benefits your business

If your business uses protective packaging, you may have already taken advantage of foam conversion.

Foam conversion is the process of turning foam material into usable products. Processes include die cutting, CNC routing, waterjet cutting, sawing, and laminating. Items created by foam conversion include protective case inserts, foam packaging such as end caps, and consumer products, including insoles, roll mats, and acoustic foam. Materials, including Plastazote and Stratocell, are commonly used by foam converters.

But what is the foam conversion process? How does it work? And how can you use this knowledge to select a foam converter for any upcoming projects or requirements?

To answer these questions, this guide covers the following:

• The typical materials used in foam conversion.
• Foam conversion methods and processes.
• The types of products manufactured from foam.

It can be surprising how commonplace foams are in everyday life. They are found in cars and vehicles to reduce cabin noise. Various materials are used in specialist aerospace applications. They are popular for various audio equipment (most notably microphones) and commonplace in insulating buildings. They are even used for sports equipment, such as shoe insoles and roll mats.

But the most common use for foam—and the one you are most likely to see on a regular basis—is protective packaging. From end caps on consumer electronics to high-performance case inserts for protecting tools, foam packaging can provide excellent protection for a wide range of items during transit.

However, it is essential at this stage to distinguish between foam manufacturers and foam converters.

Foam manufacturers, as the name suggests, produce the raw material that foam converters use. Typically using plastics (although a range of wood and plant-based foams are now becoming available), foam producers use a range of techniques to manufacture materials with different densities, properties, colours, thicknesses, and intended applications.

Large manufacturers of foam include Sealed Air and Zotefoams.

Foam converters take these materials and use various equipment and processes to convert them into usable products.

For foam packaging and inserts, the process typically involves a specialist designer analysing the products that require protection before creating a bespoke design that considers multiple factors. Key considerations include product size, fragility, outer packaging, expected handling conditions, and more.

Converters transfer these designs directly from the CAD (computer-aided design) systems to the conversion equipment.

Several materials are used in foam conversion, each with different properties, attributes and end uses. Different foam conversion processes are often suited to specific material types, meaning it is vital that specialist foam engineers and designers select an appropriate method for specific packaging applications.

The main types of foam converted into packaging are:

• Plastazote.
• Chemical block.
• Stratocell.
• Ethafoam.
• Wood foam.

There are a variety of foam conversion techniques that converters use to create foam products, such as packaging and case inserts.

The main foam conversion processes are:

• Die cutting.
• CNC routing.
• Waterjet cutting.
• Sawing.
• Splitting/laminating.
• Laser cutting and engraving.

In essence, die cutting is the process of using a cutting tool (die) to press foam to specific shapes, creating bespoke cushion packaging and case inserts. The process is also popular for non-packaging products such as upholstery foam.

Although this process can cut through only specific depths of foam (a process known as kiss-cutting), it is more common for the die to cut through the entire depth of the material.

Die cutting is carried out on a flatbed press as part of the foam conversion process. However, the requirement for tooling generally means that it is used for larger runs, where the cost of this tooling is more easily absorbed.

The advantages of die-cutting foam are its speed, consistency, and repeatability. It is ideal for higher-volume runs and particularly suited to low-density materials such as Stratocell and Ethafoam.

The main downside with die cutting is that as pressure is applied to the material, it begins to compress. Due to this, the resulting cut is not perfectly straight, with a slight concave curve to the edges. This does not affect the cut foam’s performance, however, and is merely aesthetic.

This foam conversion process is commonly used to manufacture foam end caps, foam-lined boxes, and other forms of higher-volume foam packaging.

CNC routing produces consistent, high-quality engineered foam products. Also, because physical tooling costs are eliminated (unlike die-cutting), the process can create one-off routed foam inserts very cost-effectively.

As the recesses created within the material are so precise, the resulting inserts prevent tools or equipment from moving when placed in them, significantly reducing the potential for damage. Additional software can also calculate the precise amount of material required to absorb shocks, impacts, and other forces.

The only real disadvantage of CNC routing is its speed – the process is considerably slower than die cutting, for example.

Due to this, CNC routing is commonplace when creating case inserts, shadow boards, tool control foam, and even gift box inserts.

Unlike CNC routing, waterjet cutting cannot cut to specific depths—it simply cuts all the way through the material (as die cutting does). It is also slower than die cutting, and the water used can mean some drying time is required after items are manufactured.

However, its precision means that waterjet-cut foam can be layered and stuck together to create high-performance protective case inserts. It is also popular for creating foam dunnage, which is used within tote boxes to protect automotive, aerospace, and other industrial parts and products as they move through supply chains.

Foam sawing is used across virtually all other conversion processes. As mentioned, it can trim sheets and raw material to a size suitable for other conversion equipment and size foam that has been laminated (e.g., glued together) to create neater edges.