The requirement for slim and lightweight LED luminaires has spurred the development of new housing materials. This article gives an overview of the most preferred materials in the fast-moving and diverse field of LED light housings.
By Shruti Mishra
The housing for LED lighting performs the simple yet crucial task of covering and securing the internal components of the LED lights. It also acts as a shield that protects the lights from the wear and tear caused by external elements. LED lights generate heat, and the proximity of the housing material to the LED source determines the exact thermal properties of this material. While these lights are highly efficient, they still generate heat, particularly in the case of high powered LED light sources, for which the operating temperature can vary from 80°C to 110°C.
For housing applications that will be in close proximity to the LED source, a material with excellent thermal stability is needed. Also, the material chosen for LED light housings will impact the core benefits of the LEDs. Therefore, the housing material should be chosen judiciously, so that it offers good protection to the internal components, enhances the operating life of the product, keeps the product light, and allows versatile designs while satisfying the UL anti-flammability requirements.
While selecting a particular type of housing, the first consideration is the material. The options vary from metallic to a range of engineered plastics. Each offering has different benefits and therefore the choice should be made keeping in view the eventual operating environment. Let’s have a look at some of the housing materials that are popular in the LED industry.
Extruded aluminium housings for LED fixtures offer an array of value added features that increase the multi-functionality of the LED lighting systems. As LED lights are significantly hotter than conventional lights, aluminium extrusions play a vital role in their thermal management. The excellent thermal and electrical conductivity of aluminium extrusions helps engineers to design LED lighting systems that efficiently transfer and dissipate heat, thus achieving optimal thermal efficiency. Zero surface porosity is another highlight of their highly conductive nature that leaves absolutely no scope for heat retention.
|Other advantages of aluminium extrusions
Nowadays, aluminium extrusions are designed in such a way that they can also be used as an effective heat-sink material for LED lighting, thereby reducing the need to use any additional heat-sinks. This helps LEDs to significantly outperform other light sources by maximising the lumen output and longevity of the product.
In addition, these extrusions offer customisable design possibilities with the added benefit of integrating other material in the fixtures itself. For instance, to make lighting designs compact and easy to install, designers sometimes attach reflectors and lenses with the housings for a streamlined appearance. As the lighting industry evolves, aluminium housing designs will move beyond the typical heat-sink designs to highly customised shapes. Their rugged nature meets the stringent performance standards and also helps designers to mount their products almost anywhere.
Recently, Larson Electronics launched a new white green LED light bar using an extruded aluminium housing, for industrial applications. The extruded aluminium housing of the product, LEDLB-24E-VISGREEN, is sealed against the intrusion of dust and dirt, so that the light can be used in rugged environments. Similarly, Luminis has released the Scopo range of LED projectors that also use an extruded aluminum housing. The IP66 rating, coupled with the seamless extruded aluminium housing, makes the products ideal for use in harsh conditions.
Thermoplastics are a comparatively new innovation in the LED housing space. The prime reason why this material can compete with aluminium housings is the cost. It is estimated that the price per kilogram of thermoplastics is around 20 to 30 per cent less than that of aluminium. Therefore, in spite of being a little less conductive than its aluminium counterpart, manufacturers now prefer to design their products using thermoplastics, which can significantly lower the overall manufacturing cost.
Thermoplastics are highly engineered plastic polymers that are mouldable above a specific temperature and become rock solid on cooling. From the LED light designers’ perspective, this is an excellent quality that helps them in designing some complex models. What’s more, the property makes the products robust enough to withstand high temperature and also increases their resistance to breakage. In many applications that require miniaturised designs, it is possible to down-gauge or decrease the thickness of the housing when using polycarbonates, which may not be possible with other materials.
|Other benefits of thermoplastics
The most popular types of thermoplastic materials for LED housings are polycarbonates, which are extremely robust in nature and can withstand high temperatures. The polycarbonates used for LED housings can be moulded into countless designs and shapes through injection moulding, profile extrusion, and sheet or thermo-forming processes. The best part is that designers can use special additives to enhance a material’s thermal conductivity characteristics. Polycarbonates can also be made into very thin parts, which is a major plus point for lighting applications, resulting in enhanced lumen output and greater efficacy.
Of late, many companies have embraced polycarbonates as a housing material to make the lights for wet and outdoor locations. For instance, the vapour tight LED series from Earthtronics features a fully polycarbonate housing, which provides the IP66 wet location rating for wash down and dusty conditions. The enclosure is easy to install, maintain and clean. Another launch in this category is from Maxxima, which has introduced a new line of ultra-thin emergency or warning LED lights using a durable polycarbonate housing. The polycarbonate housing in the M20388 series is only 1.27cm deep, making it ideal for automotive applications where visibility and reliability are critical.