PLASTIC ENCLOSURES FOR MARINE, AVIATION AND DEFENCE ELECTRONICS: WHAT ARE THE BEST OPTIONS?

SURVIVAL IN CHALLENGING ENVIRONMENTS

Plastic enclosures for marine, aviation and defence electronics must strike a balance between ruggedness, weight, manufacturability and compliance. While the three sectors differ in their operational extremes and regulations, there are core design principles and attributes that overlap.

Mechanical strength, sealing, thermal management, electromagnetic integrity and ease of integration (mounting, connectors, access) are vital for any good plastic enclosures for demanding environments.

Devices destined for these roles need enclosures that can resist shock, vibration, flexing and mechanical wear over time. Fortunately, modern engineering-grade plastics can deliver excellent rigidity, impact resistance and fatigue life – often with significant weight savings over their metal counterparts.

HOW STRONG MUST THE ENCLOSURE BE?

Marine, aviation and defence electronics are routinely handled by crews wearing gloves, using tools or working under pressure. Equipment can be dropped, bumped or handled carelessly during installation, transportation or maintenance.

An IK07 or IK08 impact rating confirms that the housing can withstand these knocks without cracking, deforming or compromising the internal electronics. The IK rating scale originally ran from IK00 (no protection) to IK10 (extremely high impact resistance). In 2021, an additional IK11 value was added.

Each level corresponds to an energy value measured in joules (J). It represents the kinetic energy of an impact that the enclosure can survive without significant damage.

• IK07 = 2 joules – equivalent to a 500 g object dropped from 400 mm.
• IK08 = 5 joules – equivalent to a 1.7 kg object dropped from 300 mm.

These might sound small but the impact energies simulate realistic knocks, drops or collisions encountered during maintenance, handling or environmental stress.

INGRESS PROTECTION

Environmental sealing is crucial. Enclosures specified for the outdoors must prevent the ingress of dust, salt spray, moisture or pollutants. Consider housings rated to IP 65 (protection against 30 kPa water jets), IP 66 (100 kPa temporary flooding) or IP 67 (30-minute immersion, 150-1,000 mm).

Learn more about IP ratings >>

COPING WITH COMPLEX EMC ENVIRONMENTS

EMC shielding is essential – most defence-related environments remain electromagnetically complex and hazardous. High-power transmitters, close equipment spacing, mobile platforms, and ad-hoc deployments all contribute to elevated EMC risk.

And non-combat does not mean low-EMI/RFI. Any peacekeeping, stabilisation or humanitarian and disaster relief (HADR) deployment that uses modern electronics in confined, unregulated or multi-system environments should be treated as a high-risk scenario and the right shielding should be specified accordingly. In theory, civil contingency operations are ‘medium EMI/RFI risk’ but that is still no reason for complacency.

Marine platforms are notoriously vulnerable to EMI/RFI; ships are dense metal environments that promote reflection and coupling of electromagnetic energy. Vessels carry radar, automatic identification, sonar, satellite and navigation systems – all transmitting simultaneously. Small patrol boats and unmanned surface vessels (USVs) are highly susceptible because their systems are tightly packed. Furthermore, salt water and humidity affect conductivity and grounding, complicating EMC management.

Aviation is equally high risk for EMI/RFI because aircraft are full of high-power transmitters, sensitive receivers and complex power systems, all confined within a small physical space: radar, transponders, VHF/UHF/satellite communications, Instrument Landing System (ILS), GPS, VHF Omnidirectional Range (VOR) and Distance Measuring Equipment (DME) navigational technology, and cabin Wi-Fi.

OKW ENCLOSURES FOR MARINE, AVIATION AND DEFENCE ELECTRONICS

Enclosures such as SOLID-BOX, ROBUST-BOX and IN-BOX are ideal for these demanding applications – especially when weight is a critical factor. They are regularly specified for roles where once a metal enclosure would have been the likely choice.

SOLID-BOX (IP 66, IP 67, IK08)

Wall/pole-mountable SOLID-BOX can be installed ‘lid closed’ to protect the seal and electronics. These PC+ABS enclosures feature snap-on trims that conceal the tamperproof Torx fixings. Mounting points at the rear (sizes 145, 175) match the hole patterns of VESA MIS-D 75/100.

View the SOLID-BOX range >>

ROBUST-BOX (IP 66)

These wall-mount enclosures are available in a wide range of sizes because the two case shells both have pre-moulded threads. As a result, users can decide whether the flat or the high part of the case is used as the base. Trims to conceal the fixing screws are offered in different colours as standard.

View the ROBUST-BOX range >>

IN-BOX (IP 66, IP 67, IK07 ABS, IK08 PC)

IN-BOX is a range of simple, smart and effective wall-mount enclosures. They are available in ABS (UL 94 HB) or PC. The lid (which includes a transparent option) is secured by quarter-turn screws. The complete enclosures in PC are rated UL 94 5V (better than V-0). Accessories include pressure equalisation elements, security kits and wall mounting brackets.

View the IN-BOX range >>

SMART-BOX (IP 66)

This is another tough wall-mount enclosure that can be installed ‘lid closed’. Hinged flush-fitting trims conceal the case fixings, and plastic retaining straps hold the lid in place when it is open – so there is no chance of dropping the lid or trims.

View the SMART-BOX range >>

SMALLER ENCLOSURES FOR HANDHELD AND WEARABLE ELECTRONICS

EVOTEC (IP 65)

Stylish EVOTEC is designed primarily for tabletop electronics – and it also fits neatly in the hand. Soft contours make this model comfortable to hold and operate. The sloping front desktop version can be specified with/without a recess for a membrane keypad or display. All the enclosures are moulded from UV-stable ASA+PC (UL 94 V-0).

View the EVOTEC range >>

MINI-DATA-BOX (IP 65)

OKW’s latest range of small fast-fit enclosures for sensors. These flanged ASA+PC housings can be installed quickly and easily using either cable ties or screws, making them perfect for time-critical situations (or they can be specified without flanges).

View the MINI-DATA-BOX range >>

BODY-CASE (IP 65)

BODY-CASE is a wristwatch-style enclosure for data recording, location-tracking and emergency call applications. These UV-stable ASA housings can be fitted to a standard 18 mm watch strap, suspended from a lanyard, clipped to a belt or carried loose in a pocket.

View the BODY-CASE range >>

TUNING KNOBS FOR MARINE, AVIATION AND DEFENCE APPLICATIONS

Award-winning CONTROL-KNOBS were created as the central element for menu-driven electronics. These collet knobs are moulded from durable polycarbonate with a soft-touch grooved TPE outer surface for anti-slip operation. Low-energy optional illumination – using 5 V SMD RGB LED technology – enables devices to be used in low-light conditions.

View the CONTROL-KNOBS range >>

CUSTOMISED PLASTIC ENCLOSURES

Ask us to customise your enclosure. We carry out all the work in-house to ensure quality and accountability. Our customisation services include machining, lacquering, printing, laser marking, decor foils, special materials (custom colours, V-0), EMC shielding, and installation/assembly of accessories. Register to download a 3D model so you can see how your electronics will fit in your customised enclosure.

Log in or register for 3D models >>

CONTACT US AND REQUEST A SAMPLE

Contact OKW for specialist advice on the best enclosure or tuning knobs for your application. Seek advice as early as possible in the design process – before you have finalised the PCB layout. This can help you to specify a smaller enclosure and cut costs. And don’t forget to request a sample.

Request a sample >>