The State of Thermal Dissipation Plastics for LEDs|
Article - May 25, 2017 By LarsonElectronics.com
The State of Thermal Dissipation Plastics for LEDs
Too much heat can cause lights to malfunction or fail prematurely. For LEDs, high levels of heat are mitigated through thermal-managing components. During operation, the fixture’s heat sink dissipates heat, moving it away from the unit. This movement is done in a continuous manner to ensure functionality.
Initially, LED manufacturers used aluminum for heat sinks. But now, the state of thermal dissipation trends is shifting to a new material: thermoplastics.
Heat Sink Materials and Dissipation Factors
A heat sink’s primary role is to push heat away from the LED fixture. There are several factors that can affect the performance of a luminary’s heat sink. The heat sink’s surface area must be large in order to accommodate the transfer more effectively. Designs that incorporate more fins or wider surface areas are known to boost heat dissipation. The finish of the heat sink’s surface could also affect its efficiency. Painting the surface is known to improve or increase the amount of heat dissipation.
The material used for thermal dissipation in LEDs is crucial to the heat management process. Previously, manufacturers looked to copper due to its high thermal conductivity properties; but quickly found the material to be too expensive to scale for mass production. Stainless steel was also considered at one point, due to its non-corroding features. Unfortunately, it lacked superior conducting properties that other materials supported. Aluminum was a top choice for heat sinks in LEDs, because it had high heat conduction capacity (higher than stainless steel, but lower than copper). The material is also general inexpensive, making it a great option for LED manufacturers that wanted to keep their products affordable for consumers. This development ushered in the proliferation of using aluminum for LED heat sinks in the industry.
Decreasing LED Manufacturing Costs
Thermoplastics is the latest preferred material used for heat dissipation in LEDs. Temperature tests from leading LED technology research institutions suggest that thermoplastics dissipate heat very well. When used on eight-watt and 10-watt LED bulbs, the material can keep the units below 80 degrees Celsius during operation, which is considered to be optimal, based on LED lighting industry standards. Thermoplastics can be applied to a wide range of LED fixtures, such as PAR, candle and high bay lights.
Compared to aluminum, the material offers up to seven times higher radiation ratio, and is specifically suitable to meet the demands and heat dissipation requirements of LED lights. From a manufacturing perspective, thermoplastics can reduce costs by up to 30 percent (at the rate of around $10 per kilogram of thermoplastic). Heat dissipation using thermoplastics is not as proficient as metals. However, manufacturers have been able to design heat sinks using a combination of thermoplastics and aluminum to promote its heat dissipating features.
The costs are greatly reduced during the injection molding stage, where the thermoplastics have a higher production efficiency rate than metals. In order to understand this benefit, one has to know that the process for creating aluminum heat sinks is tedious, and in some aspects, flawed for scaling. The material is required to go through numerous small processes, including polishing, buffing, drilling and anodizing. The complicated process creates bottlenecks during manufacturing. On the other hand, thermoplastics can be created entirely through injection molding, with less wastage and time spent on production.
Thermal Plastics Case Studies
PolyOne, an Ohio-based plastics technology research firm, released two case studies that display the advantages of using thermal plastic components for LED manufacturing. In the first case study, the company teamed up with engineers from Kruunutekniikka Oy of Finland, a contractor that specializes in injection molding for lighting products. PolyOne helped the company design a thermal plastic LED component that is lightweight, cost effective, corrosion resistant, IP67 rated and heat resistant. It also complies with UL94-V0 flammability guidelines.
Results from the collaboration includes the following: 10 percent in savings during manufacturing, less material requirements by up to 37 percent and less time spent on the production line due to the incorporation of injection molding machines. The manufacturer was also able to recycle scraps leftover from the process.
In the second case study, PolyOne partnered with Mars Otomotiv, an automobile lighting parts manufacturer that is based in Turkey. The company encountered issues with using die-cast aluminum heat sinks, which was supplied from a third-party. This required the group to perform tedious customizations, such as surface treatments and drilling holes, before manufacturing. During the study, the team explored non-metal options by converting its in-house metal molding process to accommodate thermoplastics. The project lasted four months, and the duo completed the transition successfully.
The Turkey-based company benefited greatly from the transition, which helped increase productivity levels on the manufacturing line (lead time and on-time order completion). Specifically, the application of thermoplastics reduced the weight of the organization’s products by up to 39 percent. It was also able to increase heat sink production by 50 percent, while decreasing costs up to 20 percent per component.