What is rohacell?

Rohacell is a closed-cell rigid expanded foam plastic based on PMI (polymethacrylimide), which does not contain any CFCs. The natural colour of Rohacell is white.

Rohacell has excellent mechanical properties, high dimensional stability under heat, solvent resistance, and has a particularly a low coefficient of heat conductivity. The strength values and the moduli of elasticity and shear are presently not exceeded by any other foamed plastic of the same gross density.

ROHACELL has very high specific strengths. The cell structure has been oriented by a special method which produces a difference in strength between the plane of the sheet and at right angles to it. In this way, and depending on the situation in which the ROHACELL sheets are installed, excellent sandwich constructions can be obtained.

For a number of uses in sandwich construction it is therefore reasonable to allow the direction of the principal stress to coincide with the direction of the highest material strength, i.e. to use the core with an upright cell structure.

*The compacted ROHACELL rigid foams are supplied as sheets. Normally they are bonded with adhesives to a height corresponding to the width of the required sandwich core. Out of the resultant block the cores are sawn at right angles to the joints so that the cell structure is vertical when the core is in a horizontal position. It is not necessary for this technique to be used in every case. If the strength values measured in the molding direction satisfy a given purpose, the ROHACELL sheets may be used flat.

Shaping of Rohacell

3/5 Axis Machining

Rohacell is machined using high speed tools designed for wood or plastics, without the use of lubricants. Dust must be carefully removed by vacuum. Common planing machines used for wood can also be used to plane edges and surfaces. Thin sheets can be cut with a knife.


Grooves, rebates and other profiles can be cut with a routing cutter. With due care the material can be cut to lap joint widths of 2mm. Parts matching the contours of a template can be done with a suitable milling cutter.


Circular saws are used for cutting sheets to size. Band, compass and jigsaws can be used for complex shapes.


Rohacell is machined using high speed tools designed for wood or plastics, without the use of lubricants. Dust must be carefully removed by vacuum. Common planing machines used for wood can also be used to plane edges and surfaces. Thin sheets can be cut with a knife.


Rohacell becomes thermoelastic and can be therefore be shaped at a temperature of 170º C – 190º C. The required forming temperature depends on the degree of shaping and the density. Care must always be taken to see that the hot air swaps uniformly over both sides of the Rohacell and that no heat is allowed to accumulate. The forming temperature must be accurately controlled in order to prevent secondary foaming. Cracks may form when shaping is rushed or done at too low a temperature.


Another possible method of shaping is cold and hot embossing. For cold embossing the requered shaped and profiles are pressed into the material into the material during which time, foam is compressed beyond its maximum compression strength. For hot embossing therefore, polyethylene of PVC foams can be sealed directly to the surface without any adhesive.

Cold Shaping

It is possible for sheets to be cold bent. For this purpose the foam plastics sheets are lined on one side with a thin, flexible skin (e.g. aluminium sheet) and bent in such a way that the skin absorbs the tensile forces. With this process, the attainable bending radii is about twice the sheet thickness.


The majority of grades of Rohacell are with us ready to be processed, including IG, IG-F, HF, WF, RIMA & XT. We are very pleased to say we have the capability in most cases to offer next day delivery anywhere in the UK as standard.

Only a few niche grades are not held in stock and will be subject to a MOQ and lead time, but we will make you aware of this at the point of your order; we will always listen to your applications and help with alternate suggestions if you require material quickly and we don’t have it in stock.

With the highly popular and widely used grades IG, IG-F & HF, no order is too small! Other grades may be subject to a MOQ and this can vary depending on the grade. Please get in touch and we will gladly take time to discuss your exact requirements and tailor your purchase for you.

We are very proud of our state of the art factory, especially after our recent expansion and we have a number of machines that will cut and prepare Rohacell along with the skilled hands of our staff. Our plant includes a Horizontal Band Saw, Sanding Plant, Circular Saw & Laser Machine. This technology allows us to engineer Rohacell to within a guaranteed +/-0.5mm tolerance, or better still, +/-0.2mm on request. With our Laser machine, we can cut complex 2D shapes with minimal waste material.

Anything you require, on request. Our cutting plant means that we can machine Rohacell to any length, width and thickness within our largest sheet sizes of 2500mm x 1250mm as well as oversized 2600mm x 1300mm on request. Maximum dimensions & thickness can depend on the grade, so ask our advice. If you need a specific sized sheet with a thickness not listed, let us know and we will accommodate for you.

Beyond our ISO Standards, Industry and Quality Assurance certifications, our continued success if built on our core business values of delivering market leading products coupled with first class customer care, from our team of dedicated and passionate individuals. We take time to listen to your needs, however big or small those are and work hard to maintain a rapport with our clients. Our facilities in Norwich mean we can cater for purchases from all over the world. We are impartial, independent and confidential; we are Emkay.

Get in touch with us on the number or email at the top of our webpage. In office hours, we have a friendly team at the end of the phone who have a vast combined expertise with Rohacell and if we don’t know the answer, we will know where to find it for you! We will talk you through the order, payment and delivery process so that you stay fully in the loop.