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OKW Enclosures Robert Cox's Enclosures Column

The development of Aluminium Enclosures over the last 40 years
April 2011

Over the last four decades, one pioneering company more than any other has led the way in the development of aluminium enclosures for the electrical and electronics industry.

It was ROLEC's founder Friedhelm Rose who was first to develop diecast aluminium enclosures in industry standard sizes and formats in the early 1970s.

OKW Sales and Marketing Director Robert Cox examines the considerable impact of ROLEC's designs on the aluminium enclosures market over the last 40 years.


ROLEC founder Friedhelm Rose's influential designs have been with us for so long that it seems inconceivable to imagine life before industry standard diecast aluminium enclosures.

But that is exactly what Herr Rose gave the industry in 1971 with the design that would become known today as the aluKOM.

In every field, standardisation is usually driven by visionaries and it was no exception with aluminium enclosures.

1971 - The first standard format diecast enclosures introduced by Friedhelm Rose

In the early 1970s, the development of electrical and electronics equipment in many different fields naturally led to the need for standardised diecast enclosures. Rose delivered precisely that with his first range of enclosures which later became the design model for many other manufacturers.

And yet Friedhelm Rose's enclosures range did more than satisfy a need, more than simply bring greater order to a product sector where previously none had existed.

It became a blueprint, the progenitor that would herald a million copies. This was, after all, the first range of standardised aluminium IP66 enclosures with internal mounting bosses in common formats.

But, as important as these enclosures were in 1971 (and still are in 2011), they marked merely the beginning.

1987 - aluNORM Single channel fixings provide more useable internal space

By the mid-1980s, the electrical and electronics industry was facing new challenges. Designers needed enclosures with greater internal space than their existing housings, but without a corresponding increase in the physical footprint.

This counterintuitive requirement was satisfied in 1987 when ROLEC launched the aluNORM range of standard diecast enclosures. This had two clever design features which set it apart.

The first centred on the mounting channels and assembly screws. Until now, enclosures had separate screws and channels for mounting and fitting the lid. But aluNORM combined both actions in a common channel with unique two-part lid assembly screws - giving designers the vital extra space they needed for their assemblies.

The second innovative feature was the aluNORM's ability to mix and match lids and bases in a wide array of options - 86 different permutations to be precise. It gave designers a huge amount of freedom when specifying the position and orientation of cable glands, switches and controls.

1997 - conFORM Shielded enclosures with cast-in contact ribs. No need for expensive EMC gaskets

Ten years later, however, the industry faced another major development with the implementation of the EC directives on EMC and the requirements for providing shielding within the enclosures.

Put simply, equipment manufacturers faced the prospect of having to ensure existing equipment passed the EC directives. As a result, the first solution was to fit the enclosures with expensive and fragile EMC gaskets in order to ensure electrical contact between all mating faces and provide a higher level of attenuation than existed before.

This was an expensive solution which commonly added 30 per cent to the unit cost of the enclosure. A more robust and cost effective solution was urgently required. ROLEC responded with conFORM, a range that separated the sealing and conductivity functions. A tough standard cost silicon gasket was used to achieve the IP66 protection class. EMC contact was provided with a series of ridges cast into the base section and a continuous rail in the lid. On assembly, the rail clamped on to the ridges - providing electrical contacts on a very short pitch (for high attenuation).

Throughout the 1990s and into the 21st century, electronics were being developed for more types of industrial application.

Electronics engineers were creating ever more sophisticated and delicate systems for use in harsher environments. They were demanding diecast enclosures that were not just tougher but also more versatile.

And more than anything, they wanted electronic enclosures that could be mounted without the need to open the lid during installation. That way, they could ensure the absolute integrity of the equipment sealed safely inside.

ROLEC's response came in 2003 with aluCASE, a completely new concept in diecast aluminium enclosures.

2003 - aluCASE Designer aluminium enclosures can be installed without opening the lid

The aluCASE range boasted many new features including a recessed lid for membrane keypads or labels; clip-on trims to conceal the fixing screws; lid retaining straps and integrated hinges.

The aluCASE was a smart, aesthetic enclosure range that could be installed quickly, easily and with maximum product security thanks to the fact that the lids no longer had to be opened during the installation process. The mounting channels were outside the sealed area and hidden by clip-on trims.

Just five years later in 2008 ROLEC went on to speed up installation still further with the launch of the aluCLIC range. Following customer research, ROLEC discovered a new trend for fast equipment replacement. Whole systems were simply replaced on-site, rather than serviced or repaired. The aluCLIC was designed to make this process very easy.

2008 - aluCLIC Enclosures with snap-on mounting device for fast installation/replacement

As the name suggests, aluCLIC enclosures can simply be clicked into place thanks to a unique snap-on mounting device on the underside of the housing. It makes changing or replacing units very fast indeed.

Fast forward two years and ROLEC launched not one but two new ranges at the 2010 Electronica Fair, both in reply to new demands from electronics engineers.

First came aluPLUS, a direct response to feedback from electrical and electronics engineers who wanted a new hybrid type of enclosure from ROLEC.

2011 - aluPLUS Advanced features for industry standard size aluminium enclosures.

The dilemma for engineers was that they liked the 2003 aluCASE range with all its extra features and its 'mount while closed' functionality - but they also wanted the industry standard sizes and formats first defined by the aluKOM type enclosures back in 1971.

So why make them choose? With aluPLUS they could have aluCASE features in standard aluKOM sizes - significantly cutting the cost of the enclosures and making them much more accessible for a greater range of projects.

The second new range launched in 2010 was aluDISC - the world's first round diecast aluminium enclosures for industrial electronics and electrical equipment.

2011 - aluDISC The first round diecast enclosures for electronics equipment.

For years, engineers working on electronic systems for cylindrical equipment or pipework had been forced to compromise the aesthetics of their designs by adding square or rectangular control housings.

Why? It makes sense to use a round housing that enhances the finished product - especially one that comes with benefits such as a keypad recess, hidden fixings and lid retainers.

And aluDISC has also another trick up its sleeve. Its circular face is complemented by two squared off mounting faces that enable easier fitting of cable glands and other connections.

Forty years on from aluKOM, aluDISC is a big step forward and one that has - like all its predecessors - been driven directly by demand.

It also illustrates how dramatically the pace of demand-led innovation in industrial enclosures has accelerated. From aluKOM to aluNORM took 16 years but from aluCLIC to aluPLUS and aluDISC has taken just two years.

And that suggests the next big innovation after aluDISC may be just around the corner.

For more information on ROLEC aluminium enclosures, contact OKW Sales and Marketing Director Robert Cox +44 (0)1489 583858, or view ROLEC's website at

To view previous issues of Robert Cox's Column click on the links below:

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