Single side aluminum based PCB for LED board

Single sided aluminum based PCB is divided into three layers: aluminum, insulating layer and copper. Aluminum is used for heat dissipation, insulating layer is for heat conduction, and copper is for conducting electricity.

Generally, one side of single-sided Aluminum Based PCB is printed with circuit, and the other side is smooth wireless circuit. The most common aluminum based PCB in the market is single-sided Aluminum Based PCB, most of which are street lamp aluminum based PCB, fluorescent lamp aluminum based PCB, spotlight Aluminum Based PCB, high-power Aluminum Based PCB, etc. the upper side is the circuit, and the lower side is connected with the shell or heat-conducting adhesive to achieve heat dissipation effect. Single sided aluminum based PCB replaces the former FR4 and PCB glass fiber PCB, emphasizing high, good heat dissipation, not easy to break and good flexibility.

The thickness of single-sided Aluminum Based PCB is 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 2.0 mm, 3.0 mm, 5.0 mm, etc., which are generally determined according to the overall thickness of the product. The drawing production of single-sided Aluminum Based PCB is generally relatively simple, which can be divided into series and parallel or series and parallel.

Single sided aluminum based PCB

aluminum based PCB structure

(1) Metal base

Aluminum base material, LF, l4m, LY12 aluminum materials are used, the expansion strength is 30kgf / mm2, and the elongation is 5%. American bages aluminum base is divided into 4 types: 1.0, 1.6, 2.0 and 3.2 mm, and the aluminum model is 6061T6 or 5052h34. Panasonic electric, Sumitomo r-0710, r-0771, alc-1401, alc-1370 and other models are aluminum based copper-clad PCB with aluminum base thickness of 1.0 ~ 3.2mm.

(2) Insulating layer

It is used for insulation, usually 50 ~ 200um. If it is too thick, it can insulate and prevent short circuit with metal base, but it will affect heat emission; if it is too thin, it can better heat dissipation, but it is easy to cause short circuit between metal core and component lead.

The insulating layer (or semi curing piece) is placed on the anodized and insulated aluminum PCB, and the copper layer on the surface is firmly bonded together after lamination.

Obviously, the size of aluminum based printed PCB is much more stable than that of insulating material. From 30 degree Celsius to 140 ~ 150 degree Celsius, the dimension of aluminum based printed PCB and aluminum sandwich PCB is 2.5 ~ 3.0%

(4) Other reasons

Aluminum based printed PCB has shielding effect, replaces brittle ceramic substrate, uses surface mounting technology at ease, reduces the real effective area of printed PCB, replaces radiator and other components, improves heat resistance and physical properties of products, and reduces production cost and labor.

Performance of aluminum based PCB

(1) Heat dissipation

At present, many double sided PCB and multi-layer PCB have high density, high power and difficult heat dissipation. Conventional printed PCB substrates such as FR4 and cem3 are poor thermal conductors, insulation between layers, and heat cannot be emitted. Local heating of electronic equipment cannot be ruled out, which leads to high temperature failure of electronic components. Aluminum Based PCB can solve this heat dissipation problem.

(2) Thermal expansion

Thermal expansion and cold contraction are the common nature of materials, and the coefficient of thermal expansion of different substances is different. Aluminum based printed PCB can effectively solve the problem of heat dissipation, so as to alleviate the thermal expansion and cold contraction of components on printed PCB, and improve the durability and reliability of the whole machine and electronic equipment. Especially solve the problem of SMT (surface mount technology) thermal expansion and cold contraction.

(3) Dimensional stability

Classification of aluminum based PCB

Aluminum based copper-clad PCB can be divided into three categories:

One is a general-purpose aluminum based copper-clad PCB, and the insulation layer is composed of epoxy glass cloth adhesive sheet;

The other is high heat dissipation aluminum based copper-clad PCB, and the insulation layer is composed of epoxy resin or other resins with high thermal conductivity;

The third is aluminum based copper-clad PCB for high-frequency circuit, and the insulation layer is composed of polyolefin resin or polyimide resin glass cloth adhesive sheet.

The biggest difference between the aluminum based copper-clad PCB and the conventional FR-4 copper-clad PCB lies in the heat dissipation. Compared with the aluminum based copper-clad PCB, the thermal resistance of the FR-4 copper-clad PCB with the thickness of 1.5mm is 20-22 degree Celsius, and that of the latter is 1.0-2.0 degree Celsius.