Enclosures: material man offers equipment view

Selecting the right material for an enclosure is dependent on many factors including application and the environment.

Typically, enclosures are manufactured from metals and plastics. These types of materials are widely available, and are popular for their different properties.

Plastics

Plastic enclosures, for instance, are often designed using ABS, polycarbonate or nylon – among other various compounds.

Enclosures made using these types of materials can be cost-effective and lightweight, making them ideal for instrumentation boxes, control systems, for holding display screens and a variety of other light duty applications.

Plastic surfaces can also be particularly glossy, which can be favourable if the application is to be visible or on display.

Metals

Metal enclosures, meanwhile, are generally selected for their strength and are typically available in stainless steel or die cast aluminium.

Stainless steel is often requested for its superior corrosion resistant properties, which are beneficial for the food industry, where the enclosure may be regularly exposed to water.

Stainless steel is also suited to applications in a marine environment, which would be subjected to salt water. For sectors such as medical and food, the need for cleanliness is imperative. Therefore, stainless steel is also highly appropriate for its clean, sanitary assets.

For other industries, impact resistance may be a priority and die cast aluminium is well known for its high impact rating.

Metal enclosures are generally selected for their strength and are typically available in stainless steel or die cast aluminium

Combined with a very robust and sturdy construction, it makes this type of enclosure an excellent choice for applications that could be bumped or knocked by vehicles, for example.

While such enclosures are often manufactured with a seal, unsealed impact resistant enclosures are available, which are designed to offer a more cost-effective solution.

This type of enclosure can also be useful for housing particularly noisy electronic equipment, as the contact between the lid and the base assist with electromagnetic compatibility (EMC) protection.

Die cast enclosures are also often obtainable with hardwearing nylon or powder coatings for increased performance such as UV protection or chemical resistance. Clearly, die cast aluminium and stainless steel enclosures are popular for industrial applications as they are hardwearing and can withstand higher ambient temperatures than plastics.

Ingress protection (IP)

IP ratings, which can be vital for correct product specification, refer to the level of protection offered by an electrical enclosure, against solids and liquids.

The letters ‘IP’ are followed by two numerals – such as ‘67’ – which indicate the degree of protection offered, according to the British Standard BS EN 60529:1992.

This means that in an environment where dust or water could damage electronic components, for instance, a sealed enclosure will be used to prevent such ingress and ensure the electronics are kept safe. They are commonly used for applications that may be exposed to the elements. Typically, they are found on offshore oil and gas platforms and within food processing plants.

• Darren Fuller is product manager at Deltron Enclosures.