Professional High Power Cooling Solution Service Provider And Manufacturers

LED Cooling

Why do leds needs cooling

Leds convert electricity into light. What's revolutionary about them is that they're a much more efficient light source than any lights source before them. Sadly, they are not 100% effective at converting energy into light energy. In the conversion process, energy is lost, in short, all the "lost" energy in the conversion process is converted into heat. If the LED is not properly cooled, it will quickly burn to death, and if unchecked, it may even reach the temperature at which the LED starts desoldering itselves from the board or strip!

In most cases, the effect is not so sudden, but rather surface over time. Most LED light strips do not show any visible symptoms of killing, but if leds without proper cooling or running at low light output only, they usually do. The most obvious symptom is that the LED light that have been running fine for a period of time (weeks/months) suddenly start to lose their leds, and they either go dimmer, change color, or fail altogether. If too many leds fail, then whole sections of the LED light can fail or even the whole led light. Leds typically have a rating of 20.000 hours or even up to 50.000 hours, but those are only true if cooled properly.

The Thermal Challenges of LED Cooling

Over the past decade, the developments of LED semiconductors have LED to important changes in LED applications, from luminous indicators to illuminators. With leds now entering several lighting fields, leds have become one of the standard methods to produce light, combining more traditional light sources such as incandescent bulbs, fluorescent lamps and high intensity discharge (HID). However, LED lighting is unique in that the light source is not a filament, gas discharge or arc, but rather a semiconductor.

This is changing the technology related to lighting development. How to solve the thermal challenge of LED cooling is the problem we need to solve at present. Here is the LED lighting solutions from Lori thermal.

Heat problem of LED light

A frequently listed advantage of LED is that they do not produce heat. In some ways, this is true, LED is cool to the touch because it usually do not produce heat in the form of infrared (IR) radiation. This obviously doesn’t go for IR specific LED.

IR radiation is what actually heats incandescent bulbs and some other light sources, making them hot to touch. Without IR radiation, LED is able to be placed in spot where the heat from other sources would cause the problem (grow lights, reef tank lights, illuminating food, etc.).

Although the LEDs are cool to the touch, there is plenty of unwanted heat within the devices themselves. Like the traditional light sources, semiconductor light emitting diodes (leds) generate heat during operation, depending on the overall luminous efficiency. Under the action of applied electrical energy, the radiation recombination of electrons and holes produces electroluminescence, and the light emitted near the PN internal needs to pass through the semiconductor medium and packaging medium of chip itself to reach the outside world (air). By integrating current injection efficiency, radiant luminescence quantum efficiency and chip external light removal efficiency, only 30-40% of the input electric energy is converted into light energy, and the rest 60-70% of the energy is mainly converted into heat energy in the form of non-radiation composite lattice vibration.

The influence of LED heat dissipation on the service life

Generally speaking, the stability and quality of LED light work are crucial to the heat dissipation of the light body. The heat dissipation of highbrightness LED light in the market is often natural convection, and the effect is not ideal. LED light made by LED light source are composed of LED, heat dissipation structure, driver and lens. Therefore, heat dissipation is also an important part. If LED cannot dissipate heat well, its life will be affected. With high power LED light, it is crucial that you dissipate heat through efficient thermal management. Without good led cooling solution , the internal temperature of the LED rises,  leading to bad change in the LED characteristics.

With the increase of LED internal temperature, both the forward voltage and the lumen output decreases. Not only is this decreasing the brightness and efficiency of the LED but this internal temperature affects the overall life of the LED as well. LEDs do not usually cause catastrophic failures (although some may, specially in the case of overheating); instead, the led’s lumen output will decrease over time. Higher internal temperatures lead to faster LED deterioration. This is why it is crucial to keep your LED internal temperature low. Also note if you overdrive the LED (putting more current to it than it’s rated current), it raises the temperature so much that it causes permanent damage.

How is the heat transferred from LED light? 

First, the led chip emits heat, which is transmitted through the base to the below led heatsink, which then dissipates it through the cooling surface where the led heatsink fin is located. Therefore, the size of the led heat sink and the area of the heat sink all determine its ability to dissipate heat. In addition, ambient temperature and drive current will affect the temperature of the LED. Other effects are the nature of light, whether it is steady state or pulsed.

LED lighting cooling solutions

Although LEDs use and dissipate much than conventional incandescent bulbs, leds still create heat in the process of converting electrons into photons. In addition, they tend to concentrate the heat they create in a narrow area. If the LED bulb or fixture is not designed to properly dissipate the heat generated, it may adversely affect the light output and life of the product, thus ensuring its failure in the market. 

With the advent of LED alternatives to incandescent, halogen lamps and even fluorescent light, engineers have been working on ways to ensure that heat is not a problem for LED lighting, and have recently come up with new led lighting cooling solutions. In many cases, the cooling mechanism relies on the traditional cooling methods of electronic devices, but applies them in new ways. But some new approaches show great promise.

Effective thermal management is the key to realizing the advantages of LED lighting. The operating temperature of the LED greatly affects the lighting color and overall life. As the LED industry moves to high-brightness LED’s (HBLED) and the high-density LED arrays, more efficient thermal management solutions are needed to maintain LED junction level operating temperature. Although standardization is common at the junction and PCB level, various lighting applications lead to highly customized cooling solutions at the led heat sink level.

In most conventional lighting applications, heat must be dissipated through a natural convection heat sink (where radiation may play an important role)to meet noise limits. However, thermal management requirements for emerging high-strength LED lighting products often exceed the practical limits of these passive cooling strategies. Integrating heat pipes, vapor chambers, fans, etc. with heat sink reduces LED temperatures and allows current heatsinks to handle higher heat flux.

How to improve LED heatsink performance.

1. LED Heatsink Material

The thermal conductivity of the led heat sink material directly affects the efficiently the heat dissipates through conduction. Copper is the best but because of its high price, aluminum is used more widely and is what the most of the heat sinks we offer here at LORI are. Like our composite LED heat sink, can be used for smaller LEDs with lower cooling requirements.Thermoplastics are useful  because they can be molded into more shapes and are weight less.

2. LED Heatsink Shape

The thermal transfer takes place at the surface of the heat sink. That is why the best heat sinks have a large surface area. In order to increase the area of the led heat sink, it is usually made into columns, mesh and other shapes. also can be achieved by straight up increasing the size of the heat sink, or by the use of heat sink fins. Finned heat sinks  help transfer more heat to the surface. Although fins help, there still needs to be enough space in between fins for air to pass through, creating a temperature difference between the fins and the air. When fins get too close to each other, the air between them will not cool and the temperature will become nearly the same as the fins, preventing them from transferring heat together. Therefore, more fins does not automatically mean better heat dissipation, you need well spaced fins.

3. LED Heatsink Contact Area 

 If there is no good contact between the led chip and the led heat sink, there will be a little impurity in the gap between the chip and the heat sink , and the heat emission of the chip will not go out, and only a small part of the heat transfer to the surface. Therefore, the chip and the heat sink fin should be in full contact, and the gap between the chip and the heat sink should not contain impurities.

4. Led Heatsink Finish

The surface of the led heat sink actually has a direct effect on thermal conductivity as well. The painted surface will actually work better than the bright, unpainted one. This also is the same for anodizing and etching heat sink which will decrease the thermal resistance and make the heat sink overall better.

5. Forced Convection (Air Cooling)

As I said earlier, for larger LED arrays or lights that are in the enclosure where their isn’t much air flow you might want to consider using some sort of ventilation system. This will help because the air surrounding the heat sink will in turn be cooler and allow for better heat transfer from the heat sink surface to outside. Our LED heat sink kits come with a fan included.

Led Heatsink

As an important part of industril lighting, LED light has the advantages of low cost, stable luminescence, energy saving and environmental protection, and it is favored by the government and society. With the rapid growth of world's economy, more and more places will be built with led heatsink for LED street light, household lighting, industrial lighting, automotive lighting, green house let light etc. and each application has its own environmental conditions.

Led heatsinks are an important part of LED lighting because they provide the path for heat to travel from the LED light source to outside elements. Led heatsinks are able to dissipate power in three ways: conduction ( heat transfer from one solid to one solid), convection (heat transfer from one solid to the moving fluid, air in most cases), or radiation (heat transfer from two objects at different temperatures by thermal radiation). LED heat sinks are usually used in natural convection environments.

So It can be seen that the LED  heatsink is still facing great demand in the future, and the high-quality and durable street light can ensure the continuous lighting, and ensure the trust and love of users. The big problem faced by the LED light in the use process are thermally solutions and heat sink structural, because the led light will be on all night, the heat generated by long time of work can not be underestimated, especially in summer , once the heat dissipation can not be stabilized in time, it will burn out.

 LED heatsink types

Lori related led heatsinks

professional high power custom led heatsink manufaturer and led thermal solution provider.

 

High power led heat sink
Round led heat sink
LED heatsink manufaturing methods

As a professional high power led light cooling solution service provider and custom led heatsink manufaturer, Lori committed to producing reliable and durable led heat sink for LED light, providing high efficiency and stable heat dissipation for LED light, and helping the safe and lasting lighting of LED light . This led heatsink uses aluminium 6063, high purity, no impurities, thermal conductivity of 155-160. It not only has beautiful appearance, light weight, but also strong heat dissipation capacity, very suitable for matching with sunflower aluminum heat sink LED light. Lori led heatsinks have different manufacturing process, so led typs are  extruded aluminum heat sink, Die cast aluminumheat sink, Stamping heat sink, cold forged heat sink, differnt process led heat sink have differnt features and use for different industuril. 

1. LED extruded aluminum heat sink manufacturing and features

LED extruded aluminum heat sink is formed by aluminum extrusion, and by CNC machining, embedded in heat pipe, and finally finished by surface treatment. Led aluminum heat sink is liquid aluminium formed through a fixed mold. Then cut the led heat sink aluminum profile and mchined into the desired shape. The post processing cost is high, and the heat sink fin can be made very thin to increase the heat dissipation area. When the led heatsink works, air convection diffusion heat automatically formed, and the thermal conductivity is good. Common materials used in aluminum extrusion are AL6063 and AL6061. LED extruded aluminum heat sink shape are round or square, for the round heat sink we called sun flower heat sink.

  1. LED aluminumextruded heat sink features include:
  2. 1. it has relatively low mold cost
  3. 2.It can be customized in various shapes and size.
  4. 3. Heat sink fin can be done very thin , good thermal conductively.
  5. 4. The cost of post machining is relatively high,The forming is relatively simple,the shape of aluminum extrusion die is relatively single, and many of its features are mainly made up by post-processing.

LED Die cast aluminum heat sink manufacturing and features

Die casting heat sink is a kind of pressure casting parts, it is manufacturing by the die casting machine, which installed pressure casting mold, the heating for liquid copper, zinc, aluminum or aluminum alloy into the mouth poured into the die casting machine, die casting machine die casting, casting the shape and size of aluminum or aluminum alloy parts, such parts are usually called aluminum die casting heat sink. LED Die-cast aluminum heat sink are generally large in size, with irregular design and controllable production cost. The heatsink cannot be made very thin, so it is difficult to maximize the heat dissipation area.The commonly used die casting materials for the LED heatsink are ADC10 and ADC12.

LED die casting heat sink Features:

1.die casting heat sink can produce many complex shapes, with high precision and smoothness

2. There will be flow marks on the surface of the die casting heat sink, so the die casting heat sink needs to be polished

3. Die casting heat sink mould costs a lot, and heat dissipation is poor compared with other processes

4. High production efficiency and multi-hole mold

 Cold forged heat sink manufacturing and features

Cold forged heat sink is made by steel, aluminum alloy sheet stamping, pull to rise, make a cup of tube type of heat sink, cold forged heat sink inside and outside perimeter smooth, LED cold forged heat sink commonly used aluminum alloy material is AL5052, AL6061, AL6063, the quality of cold forged heat sink is small, high material utilization, high production efficiency, is a low cost solution.This process is mainly used in the manufacture of LED light heat sink.

Led stamping heat sink manufacturing and features

LED Stamping heatsink is a forming and processing method that relies on press and mold to exert external force on plate, strip, pipe and profile to produce elastic deformation, plastic deformation or separation, so as to obtain the required shape and size of the stamping heat sink .

Stamping and forging belong to the same plastic processing (or pressure processing), collectively known as forging. Stamping materials are mainly hot and cold rolled steel and steel strip. Compared with die casting heat sink and forging heat sink, stamping heatsinks are thin, even, light and strong. The quality of stamping heatsinks is very small, the material utilization rate is high and the production efficiency is high.

All in all, with the increase of power level and the reduction of package size, LED design engineers are faced with more demandingthermal management requirements. Solutions that use conventional metal passive heat sink become thermally inefficient and are too bulky and bulky for newer LED products. The thermal diffusion technologies (such as heat pipes, vapor chambers, fan) can provide excellent thermal management solutions for higher power, densier LED devices cooling. Please contact us to discuss your specific LED thermal management application with Lori teams.

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