How can high quality heat conducting plastics be embodied?

When we usually use some electronic products, if we want the products to be better used the overall service life to be longer, then some ordinary maintenance care are naturally very important, such as the place they are placed, as well as the daily cleaning so on. In addition, self heating is the performance of the product itself, such as the configuration of some parts. Just like the heat-conducting materials used in large electrical appliances, it may be strange to many friends. But in fact, we often use notebooks LED lights, etc., are also used. So what can we talk about today to show the high quality of thermal conductive plastics?

一、 What are the characteristics of thermal conductive plastics?

1. Uniform heat dissipation. In the process of use, it can realize uniform heat dissipation, effectively avoid hot spots, reduce the deformation of parts caused by high temperature partially completely, adjust the physical properties of heat-conducting plastics, such as improving mechanical properties, increasing strength stiffness; adjust its conductivity according to the needs, make insulating, conductive antistatic heat-conducting plastics.

2. Light weight. The heat conducting plastic is about 50% lighter than aluminum, which can reduce the vibration to the finished equipment improve the stability of the equipment.

3. The choice of base material is extensive widely used. Thermal conductive plastics have a wide range of options, which can be selected a variety of basic resins such as PP, ABS, PC, PA, PPA, PBT, LCP, PPS, Pei, peek even elastomers. According to the product needs, the physical properties of related plastics can be selected, the relatively low-cost plastic substrate can be selected to reduce the product cost. Therefore, it is widely used.

4. The thermal expansion coefficient molding shrinkage of thermal conductive plastics are low, which can be used for products with high requirements for dimensional stability.

5. It is very convenient to process shape. Heat conducting plastics have the same processing technology as ordinary plastics. They can be rapidly formed in large quantities without secondary processing, which greatly shortens the molding cycle of products. It can be made into a more complex shape, so as to improve the product design freedom product added value.

6. Low working temperature high temperature resistance can improve the service life of components equipment.

二、 How to understand the properties of heat conducting plastics?

The thermal conductivity of thermal conductive plastics depends on the interaction between polymer thermal conductive fillers, different fillers have different thermal conductivity mechanisms.

1. Metal filler: the heat conduction of metal filler mainly depends on the electronic movement, which is accompanied by the heat transfer.

2. Nonmetallic fillers: the heat conduction of nonmetallic fillers mainly depends on molecular heat conduction, the heat diffusion rate mainly depends on the vibration of adjacent atoms binding groups, including metal oxides, metal nitrides carbides.

三、 How to choose thermal conductive plastics?

1. Thermal conductivity: as a key technical index, the thermal conductivity of materials various manufacturers is concerned by users. But the technical standards for measuring thermal conductivity are different. Even under the same technical standards, the test methods are different. For example, there are plate method laser method. Under different test methods, the error range of test results is totally different. Generally, the precision of laser method is higher than that of plate method, the equipment involved in laser method is basically dependent on imports expensive.

2. Material fluidity: usually, the melt index is used to express the heat conducting material with good fluidity, which is easy to form smooth to produce. Based on the high fluidity heat conducting plastics, the wall thickness of the radiator can be designed to be relatively thin, usually 1-1.2mm. Because of the thin wall thickness, the heat path will be shortened, so as to improve the heat dissipation effect. At the same time, the thinner wall thickness will reduce the weight of the material reduce the cost of the material. If it is a material with poor fluidity, it is usually easy to be injection molded, it will easily damage the mold increase the maintenance cost of the mold.

3. Forming shrinkage: generally, when the thickness is 3mm, the qualified forming shrinkage should be below 0.5%, more than 0.8% will have an adverse impact on the dimensional accuracy of radiator, the smaller the forming shrinkage, the better. If the material with higher molding shrinkage is selected, the wall thickness will have to be increased to make up.

4. Mechanical properties: the mechanical strength of heat-conducting plastic radiator depends on several key indicators: impact strength of cantilever notch, tensile strength bending strength. Generally, indicators of different materials can be compared. The larger the indicator value, the better. Thermal conductive plastics with excellent mechanical properties can be added to the radiator structure with snap design, so that the interface between PC cover lens radiator can be realized by snap, so as to avoid completely relying on adhesive to fix. The problems of viscose are: curing time is needed, delivery time is extended, at the same time, the glue is easy to atomize under high temperature, which affects the light effect.

5. Flame retardant characteristics: there are two key points: first, whether it conforms to UL94V0 flame retardant grade will be more critical for export to the U.S. market; second, whether it is halogen-free flame retardant. In short, the flame retardant should contain halogen, otherwise the environmental protection grade of the material will decline, it is difficult to pass Europe RoHS, reach.

6. Insulation characteristics: one of the advantages of thermal conductive plastics is the insulation reliability. If the injection molded heat dissipation shell can withstand the high voltage of more than 3500v, it should be easy to pass the safety test. Matching with such an insulating shell, the lamp board power supply scheme can be more flexible, including: high voltage linear lamp beads + high voltage linear power supply, non isolated power supply + medium power lamp beads.

7. Coefficient of thermal expansion: if the structure of plastic clad aluminum is adopted in the radiator structure, the difference of coefficient of thermal expansion between the outer layer of thermal conductive plastic the inner layer of aluminum alloy should be considered. The coefficient of thermal expansion of aluminum alloy is 0.000024mm/mmk, the coefficient of expansion of thermal conductive plastic should be at the same quantity level, otherwise it will cause the failure of synchronous thermal expansion cold shrinkage, resulting in the cracking of the radiator shell.