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Die-cutting of heat-dissipating materials: knowledge of conductive graphite film that you don't understand
- 2019-04-25-

At present, the heat-dissipating material die-cutting widely used in the industry is a graphite heat-dissipating material processed by graphite. What is a thermally conductive graphite film? Let's have a big popularity today, not much nonsense, and the students who want to know look down.

What is the heat-dissipating material die-cutting graphite film?

Compared with metal materials such as aluminum and copper, graphite has the characteristics of high temperature resistance, small thermal expansion coefficient, good thermal conductivity, stable chemical properties and large plasticity, which enables better heat conduction and faster heat transfer. The electronic device is unusable due to excessive heat during use.

At the same time, graphite has a good soaking effect, which can effectively prevent local overheating of electronic products.

Classification of thermally conductive graphite film

According to different manufacturing methods, thermal conductivity, size and thickness, graphite heat-dissipating materials can be divided into natural heat-conducting graphite sheets, synthetic heat-dissipating graphite films and nano-composite graphite films. Among them, the natural heat conductive graphite sheet is a graphitized film obtained by a chemical method under high temperature and high pressure, the thermal conductivity is 800-1200 w/mk, and the thinnest thickness is 0.1 mm.

Synthetic graphite film is a carbon crystal high crystalline graphite film produced by graphite synthesis method under extremely high temperature environment. The thermal conductivity of the crystal surface of the film is 1500-2000W/mk, and the thickness can reach 0.03mm. It is an ideal soaking material for eliminating local hot spots, and can act as a heat transfer bridge between the hot spot and the heat sink.

The nano-composite graphite film is made of expandable graphite, and is subjected to high-temperature expansion and ultrasonic vibration treatment to obtain nano-graphite, and further oxidize and reduce the nano-graphite to obtain re-oxidized graphite and reduced graphite, which are combined with nano-graphite and re-oxidized graphite. A heat-dissipating material prepared by recombining a conductive filler such as graphite has a thermal conductivity of 1800-2500 w/mk and a thickness of 0.03 mm.

Since the process of the nano-composite graphite film is complicated, the cost is high, and the available fields are limited, the current demand for the nano-composite graphite film is low. Graphite heat-dissipating materials have been widely used in smart phones due to their good heat dissipation characteristics, successfully solving the heat dissipation problem of mobile phones. In the future, with the miniaturization and thinning of electronic products, graphite materials will be widely used in electronic products such as mobile phones and tablet computers, and become the main material for solving the heat dissipation problem of electronic products, and promote the healthy and rapid development of the graphite heat dissipation material industry.

Characteristics and application of graphite film

The thermally conductive graphite film is a new heat-conducting heat-dissipating material that conducts uniform heat conduction in both directions and shields heat sources and components while improving the performance of consumer electronics. The thermally conductive graphite film has ultra-high thermal conductivity, easy operation, low thermal resistance and light weight. According to the performance characteristics can be divided into: synthetic thermal graphite film and natural thermal graphite film.

Thermal graphite film applications: IC, CPU, MOS, LED, heat sink, LCD-TV, notebook computers, communication equipment, wireless switches, DVD, handheld devices, cameras / digital cameras, mobile phones, etc.

Graphite film processing method

Adhesive processing

In order to better adhere to the ic and electronic component circuit board, the surface of the heat conductive graphite sheet needs to be back-coated, which can be divided into two types: double-sided adhesive and single-sided adhesive.

Film processing

Some products require insulation and insulation in the circuit design, and the thermal graphite sheet itself is electrically conductive. At this time, it is necessary to carry out lamination processing on the surface of the thermal graphite sheet to optimize the product performance.

Edge processing

In the die-cutting process, the edge is easy to fall off, and sometimes the heat-conducting graphite sheet is edged.

The graphite film on the outer surface of laptops, LEDs, and digital cameras is partially peeled off or thin, and what is the impact on the work of the product? A small amount of the falling off of the graphite film layer does not work normally, and it can be left untreated. If it falls off more, use 6B pencil to coat off the thin or thin area, then use the multimeter Rx1K side and apply the resistance between any two points of the layer (should be no more than 10-20 kohms). In order to prevent the coated pencil powder from being knocked out, a layer of varnish can be applied as a protective layer.

Graphite film product characteristics

Versatility: The surface can be combined with other materials such as metal, plastic, and self-adhesive to meet more design functions and needs.

Low thermal resistance: thermal resistance is 40% lower than aluminum and 20% lower than copper;

Light weight: 25% lighter than aluminum and 75% lighter than copper;

High thermal conductivity: The graphite heat sink can be smoothly attached to any flat and curved surface and can be cut in any form according to customer's requirements. Ultra-high thermal conductivity in the plane of 1200 W/mK.

Graphite film industry competition pattern

The use of heat-dissipating material die-cutting began with the rapid development of consumer electronics products. It began to be used in large-scale smartphones in 2011 and is an emerging industry.

The earliest companies in the field of graphite heat-dissipating materials were foreign companies, including Matsushita of Japan, Graftech of the United States, and Kaneka of Japan. Domestic graphite heat-dissipating materials manufacturers are relatively few, including carbon yuan technology, Siquan new materials. Affected by the late development of the industry, the concentration of domestic graphite heat dissipating materials industry is relatively low. With the advancement of technology of various manufacturers, the development speed of the industry will increase, the competition will be more intense, and the concentration of the industry will gradually increase.