Foam

Foams are materials with a cellular structure made of polymer or elastomer, in which gas fractions are enclosed within the material. The ratio of density, cell structure and base polymer controls damping, insulation and resilience and thus determines suitability for technical applications.

For selection in operational use, the following criteria are particularly important:

• Density as the basis for weight, strength and damping
• Cell structure (open-cell or closed-cell) as the basis for absorption behaviour and sealing effect
• Mechanical properties such as compression set and restoring force
• Temperature and media resistance depending on the base material

For cut pieces, seals and protective layers in technical environments, the overview of technical foams is often a suitable starting point, as it allows variants and typical applications to be clearly distinguished.

Fundamentals and properties of foams

The functional properties of foams result from the combination of cell structure, density and the base material used. These parameters define whether a foam damps, seals, insulates or provides mechanical support.

Cell structure: open-cell or closed-cell

Open-cell foams have interconnected cells. They absorb air or liquid and exhibit a soft, strongly damping behaviour. Closed-cell foams have completely sealed cells. They are dimensionally stable, water-repellent and suitable for sealing or insulating tasks.

Density and resilience

Density describes the ratio of material to enclosed gas. Low densities enable high elasticity and low weight, higher densities increase compressive strength and service life. Resilience determines how quickly and completely a foam returns to its original shape after loading.

Mechanical and thermal properties

For industrial use, properties such as compression set, long-term elasticity and temperature resistance are decisive. These properties vary depending on the polymer base and influence the application limits in mechanical engineering, automotive engineering or electrical engineering.

A detailed differentiation by material base is provided by the overview of materials and material types, as foams can be clearly distinguished there from solid materials.

Material types of foams

Technical foams differ primarily in their base material. This determines the temperature range, media resistance, elasticity and ageing behaviour and is therefore decisive for the service life in an industrial environment.

PU foam (polyurethane)

PU foams are predominantly open-cell and are characterised by good damping properties and high elasticity. They are frequently used for padding, vibration damping and acoustic applications.

PE foam (polyethylene)

PE foams are closed-cell, dimensionally stable and water-repellent. Typical applications are protective packaging, insulation and lightweight spacers.

EPDM foam

EPDM-based foams combine elasticity with high weather and ozone resistance. They are suitable for outdoor sealing applications as well as for technical sealing profiles with moderate temperature exposure.

Silicone foam

Silicone foams cover a wide temperature range and retain their elasticity even under continuous thermal load. They are preferably used in electrical, medical and food technology.

A material-related deepening with further properties and resistances can be found in the overview of foams by material.

Typical areas of application for foams

Foams perform clearly defined functions in technical applications. Selection is based less on the product name than on the required effect in the component or system.

Damping and vibration isolation

Open-cell and elastic foams reduce vibrations, noise and impact loads. They are used in machine housings, units and electrical assemblies to protect components and reduce noise emissions.

Sealing and sealing off

Closed-cell foams are suitable for surface and gap seals. They seal against dust, moisture and air movement and are frequently installed as cut pieces or sealing strips.

Insulating

Due to the enclosed gas fraction, foams have a heat- and sound-insulating effect. This property is used in housing technology, plant engineering and technical packaging.

Protecting and maintaining spacing

Dimensionally stable foams serve as protective layers, spacers or transport securing devices. They prevent damage to sensitive surfaces and components during assembly, storage or transport.

For functional solutions with defined dimensions, the foam cut pieces section offers a practical classification by application requirement.

Selection criteria for foams

The selection of a suitable foam is based on clearly definable technical parameters. The decisive factor is the coordination between mechanical load, ambient conditions and the desired function.

Density and compressibility

Density influences weight, strength and damping behaviour. Low densities are suitable for soft damping, higher densities for sustained loads and dimensionally stable applications.

Temperature range

The permissible service temperature range determines whether a foam remains permanently elastic or becomes brittle. High-temperature-resistant materials are used near heat sources or in industrial processes.

Compressive load and restoring force

The compressive load in the installed state influences the service life. A low compression set ensures that the foam fulfils its function even after repeated loading.

Environmental influences

Moisture, oils, chemicals or UV radiation have different effects depending on the material. Material selection therefore always takes the specific application environment into account.

For practical solutions with defined dimensions, the custom-cut foam section offers direct implementation of technical requirements.

Processing and cutting of foams

Foams can be processed using various methods. The choice of cutting and shaping method influences dimensional accuracy, edge quality and repeatability.

Formats and material thicknesses

Foams are available as sheets, rolls or blocks. Material thicknesses and densities are selected according to the required function and installation situation.

Cutting methods

Depending on the material and requirement, knife, waterjet or punching methods are used. These methods enable precise contours, series parts or individual cut pieces with reproducible quality.

Tolerances and fit accuracy

The achievable dimensional accuracy depends on the foam type and the method. For technical applications, tolerances are defined in advance to ensure reliable function in the component.

Bonding and assembly

Foams can be supplied self-adhesive or mechanically fixed. The choice of adhesive system depends on the substrate, temperature range and load.

A concrete implementation of technical requirements is made possible by the cutting and moulded parts section with individually defined dimensions.

Quality, standards and technical classification

The quality of technical foams can be objectively assessed using defined test values and standardised parameters. These values serve as a basis for decision-making in design, purchasing and quality assurance.

Density and material consistency

A uniform density across the entire material volume is an indicator of reproducible properties. Deviations have a direct effect on damping, compression behaviour and service life.

Mechanical test values

Tests such as compression set, compression hardness and continuous load provide information on long-term stability. These properties are determined according to recognised test methods.

Temperature and media resistance

Resistances to heat, cold, moisture or chemicals are tested specifically for each material. They define the application limits in an industrial environment.

Standards and specifications

Technical foams are based on common industry and material standards. These ensure comparability and support safe integration into existing systems.

A cross-material classification is provided by the overview of material testing and quality, in which test methods and properties are brought together.

Differentiation from other materials

Foams fulfil specific functions through their cell structure. For certain applications, however, other elastic materials offer technically more suitable properties.

Foam and solid rubber

Solid rubber has a compact structure without gas fractions. It is suitable for applications with high mechanical load, precise force transmission and low deformation. Foams are used when damping, weight saving or insulation are the priority.

Foam and cellular rubber

Cellular rubber is one of the closed-cell elastomer foams. It combines a uniform cell structure with high elasticity and is suitable for permanent seals. Classic foams, on the other hand, cover a broader spectrum of damping and protective functions.

Foam and sponge rubber

Sponge rubber has a fine-pored, elastic structure and is frequently used for light sealing and protective tasks. Foams offer a greater range of densities and mechanical properties depending on the material base.

A structured comparison of elastic materials is provided by the overview of elastomers and rubber materials.

Summary and orientation

Foams are versatile materials with a cellular structure whose properties can be specifically adjusted via the material base, density and cell structure. They are particularly suitable for applications where damping, insulation, sealing or protective functions are required.

Selection is always application-related. Mechanical load, temperature range and ambient conditions define whether an open-cell or closed-cell foam is technically suitable or whether alternative elastic materials offer advantages.

For a structured continuation from material selection to concrete implementation, the foam solutions section is a recommended starting point, in which materials, cut pieces and technical variants are brought together.

Frequently asked questions about foams

What is foam in the technical sense?

Foam is a polymeric material with a cellular structure in which gas fractions are enclosed within the material. This structure controls damping, weight and insulation.

What is the difference between open-cell and closed-cell foam?

Open-cell foams have interconnected cells and damp strongly. Closed-cell foams have sealed cells and are suitable for sealing and insulation.

Is foam a plastic?

Foams are based on plastics or elastomers. The base material determines the temperature range, elasticity and resistances.

Which foams are suitable for technical applications?

For technical applications, foams with defined densities, reproducible properties and tested resistances are used.

Can foam be manufactured to measure?

Foams can be manufactured as cut pieces or moulded parts with defined dimensions and tolerances.

A material-related selection aid is provided by the overview of foam cut pieces for technical applications.