Specifying enclosures tough enough for industry and outdoors

In this article, Rolec walks electronics buyers through the dos and don’ts of purchasing electronics enclosures destine for harsh working environments

Harsh industrial environments pose three main hazards to fragile electronics: impact, dust/water ingress and chemicals. Sometimes the threat can come from all three simultaneously. However, the sheer robustness and water resistance of an enclosure may not be enough. Specifying the correct material and technical features are equally important—because even the toughest housing can have an Achilles heel.

Impact is the obvious risk in many industrial applications, which is why diecast aluminum enclosures are often the first choice. They are strong, light and corrosion resistant. Aluminum dissipates heat well and can withstand a wide range of chemicals.

However, durability must mean more than just the thickness of the enclosure walls. Diecast enclosures such as aluDOOR feature strong integrated lid hinges with A2 stainless steel lid screws and threaded inserts for corrosion-resistant assembly in extreme conditions. The lid is screwed shut with tamperproof Torx screws. The seal is a continuous foamed-in gasket that offers better protection from dust and water because there is no join that could weaken.

Specifying GRP and diecast aluminum enclosures for tough industrial electronics
AluDOOR diecast aluminum enclosures for high-performance industrial electronics
PolyDOOR (left) and polyTOP (right) are highly resistant GRP polyester enclosures for electronics and electrical systems

Ingress protection is always a critical factor for industrial electronic enclosures. IP66 enclosures are completely dust-tight, with protection against temporary flooding (such as in heavy seas).

IP67 enclosures must be able to withstand immersion (150mm to 1m) for at least 30 minutes. IP68 takes this protection a stage further with the agreed depth and duration greater than those specified for IP67.

Meanwhile, IP69K enclosures can cope with high pressure water jets and steam cleaning. This is essential for sectors such as food processing, chemicals, agriculture and auto manufacturing. (aluDOOR is rated to IP66, IP67, IP68 and IP69K.)

However, specifying the highest number rating may be wrong for the application. This is particularly true for NEMA ratings, the US equivalent of IP. NEMA and IP correlate approximately but there are pitfalls. For instance, NEMA 6 is similar to IP67 but NEMA 12 is more like IP52, which is insufficient for situations requiring IP66, IP67, IP68 or IP69K protection.

Metal enclosures are not the only option. Tough thermoplastic housings are increasingly being used to safeguard industrial electronics. A case in point is technoPLUS, a plastic housing for pole-mounted devices.

It is molded from UV-stable ASA which can withstand the sun’s rays far better than ABS. Being rated IP66, IP67 and IP69K, it can resist temporary flooding, immersion and also water under pressure—such as the destructive combination of heavy rain and strong winds.

Chemicals represent the other major threat. As good as aluminum enclosures are, it can often be better to specify glass-fiber reinforced polyester (GRP) housings for locations where aggressive substances pose a hazard.

GRP is inert to many chemicals and its dense structure makes it highly impermeable to liquids and gases. GRP enclosures such as polyTOP (IP66, IP67) and polyDOOR (IP66) can withstand a wide range of acids, alkalis, solvents, oils and other corrosive substances.

These include sulfuric acid, sodium hydroxide, acetone, ethanol, diesel, gasoline, chlorine and ammonia. However, while GRP is highly resistant to many chemicals, its performance may vary depending on factors such as temperature, concentration and length of exposure.

When specifying industrial electronic enclosures, always choose a manufacturer that can provide the full range of customization services in-house: CNC machining, engraving, display windows, powder coating, painting, photo-quality printing and assembly of accessories. This ensures quality and saves time and money.