There are numerous firms involved in manufacturing plastic enclosures which widens the consumer choice. But some can be little more than a disaster waiting to happen. Here, Steve Gallon examines some of the key issues surrounding the original equipment manufacturer selection procedure.

The use of polycarbonate and polyester enclosures is becoming well established in the original equipment manufacturer (OEM) industry.
There is now an array of companies manufacturing plastic enclosures. However, there are some concerns arising from this trend. Some 'cheaper' versions are manufactured from inferior materials - a hazard waiting to happen, for example, when some materials burn, toxic gases are given off.
Mindful of these health and safety issues, Fibox only uses high grade, UL 94 certified materials. The enclosures carry nine other European approvals. The company manufactures enclosures from glass reinforced polycarbonate and polyester, or ABS where cost is an issue. Customers demand and are supplied with quality products. The enclosures are strong enough to park a car on without causing damage.

Hostile environments

At the same time, as all these polycarbonate enclosures are UV stabilised and IP67 rated, they can be used in hostile environments. They are used to safely house very valuable electronic and electric circuitry.
Customers have peace of mind, knowing that they can 'fit and forget' - an important feature when aiming to reduce maintenance costs. In all, 550 sizes are available.
The move away from steel housing for OEMs is gaining momentum. Historically steel has been far longer used for housings than plastics. However, though steel is often specified out of habit, design engineers now realise the inherent strengths of the plastic enclosures and that there are several drawbacks to using steel.
For instance, if a steel door is dented this will cause ingress - especially undesirable in hostile environments.

Rusting housings

In addition the steel housings will eventually rust, leading to a higher replacement rate than plastic enclosures. Indeed, some customers who fitted plastic enclosures 25 years ago still do not need to consider replacements.
So, when thinking of the whole life and maintenance costs, having plastic enclosures is a definite bonus.
Further trends are occurring in the enclosure market place. Plastic enclosures can offer far more flexibility when it comes to the customisation option. This will transform a basic housing into a specialised item.
Customisation can take many forms, from a single machine drilled hole for a cable to an individually designed housing with a clear plastic face for easy viewing of instruments.
More than 40 per cent of Fibox's customers have already taken advantage of the complete in-house service offered by the company, which has five engineers on hand ready to answer questions and offer advice.
At its simplest, enclosures come with ready-made holes and openings supplied to the customer's specifications. Fibox, however, uses the technique of producing a totally customised enclosure through a mould in multi- parts, rather than the usual two piece.
The mould has four slides, all of which may be modified to meet the customer's requirements. A flange interface, for example, may be added to the enclosure simply by altering one of the sides. The result is very little extra cost to the customer as most of the tools are in standard form and already available.

Aesthetic looks

Coloured enclosures are becoming more popular as customers demand a more aesthetic look to their end product. A corporate image or colour can be followed through in all products. Plastic raw material readily accepts colour pigmentation.
The ability to satisfy customers' requirements will give any company the edge, and as enclosure manufacturers adjust to ever changing trends, flexibility and the capability to meet both off-the-shelf and customisation requirements is the way to keep ahead of the competition.

Steve Gallon is with Fibox, Middlesbrough, UK. www.fibox.com