What is ROHACELL®?

What is Rohacell
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Rohacell is a rigid structural foam made from polymethacrylimide, commonly abbreviated as PMI. It is a lightweight core material used in high performance sandwich composite structures where strength, stiffness, thermal stability, and dimensional accuracy are critical.

Rohacell is engineered and manufactured in Germany and reflects a long tradition of German materials engineering. Its development was driven by aerospace requirements, where predictable performance, tight tolerances, and repeatability are essential. This engineering discipline is one of the main reasons Rohacell is widely regarded as the leading composite core material.

The material combines very low density with high compressive strength, high shear strength, and excellent creep resistance. Unlike many conventional foams, Rohacell maintains its mechanical properties under long term load and at elevated temperatures, allowing composite structures to retain performance throughout their service life.

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Material structure and performance
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Rohacell has a closed cell structure with a highly uniform internal microstructure. Resin uptake during processing is very low, which helps control laminate weight and ensures consistent fibre volume fractions. The uniform structure also contributes to predictable machining behaviour and reliable bond performance.

Rohacell is most commonly used as the core in sandwich composite structures bonded between skins such as carbon fibre, glass fibre, or aramid. In these structures, the outer skins carry tensile and compressive loads, while the Rohacell core separates the skins and resists shear. This geometry driven approach delivers high bending stiffness with minimal added weight.

German engineering and tight process control are central to why Rohacell is considered the benchmark composite core. Manufacturing consistency ensures reliable density, mechanical properties, and thickness tolerances across production batches. This level of control is critical in industries where material variability cannot be tolerated.

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Processing and manufacturing
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Rohacell is known for its excellent processing characteristics. It can be CNC machined, sawn, waterjet cut, laser cut, bonded, and thermoformed. It machines cleanly, producing fine plastic dust rather than fibres, and supports the manufacture of complex three dimensional core geometries with high accuracy.

Thermal stability is a defining advantage of Rohacell. Depending on the grade, it can withstand processing temperatures of approximately 180 to 220 degrees Celsius. This enables compatibility with autoclave cured prepregs, high temperature resin systems, and demanding composite cure cycles.

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Grades and availability
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Rohacell is available in a wide range of grades and densities. Lower density grades prioritise minimum weight. Medium density grades balance strength, machinability, and surface durability. Higher density grades provide increased compressive strength, edge stability, and handling robustness.

Special grades are available for high temperature processing and for radio frequency and electronic applications where low dielectric constant and low dielectric loss are required.

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Industries that rely on Rohacell
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Industries that rely on Rohacell include aerospace, space, motorsport including Formula One, unmanned aerial vehicles, defence, medical equipment, industrial tooling, automotive lightweight structures, and radio frequency and microwave engineering.

In these sectors, Rohacell is selected for its proven performance, reliability, and consistency rather than cost alone.

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Rohacell distribution and support
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Emkay Plastics is an official distributor of Rohacell and operates across more than seventeen distribution territories. Emkay Plastics supplies Rohacell in a wide range of grades, thicknesses, and formats, including precision cut sheets and custom machined components.

As an official distributor, Emkay Plastics provides genuine material with full traceability, technical support, and application guidance to customers across aerospace, motorsport, and industrial markets.

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Summary
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Rohacell is not a general purpose foam. It is an engineered structural material designed to enable lightweight, high stiffness composite structures. Its combination of German engineering, long term proven performance, broad grade availability, and global distribution has made Rohacell the reference standard for composite core materials.

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