The following is the introduction to the characteristics and substrate of metal PCB arranged by China circuit board factory.
Metal core PCB features
1. The heat dissipation
Conventional PCB substrates are generally poor conductors of heat, and the heat emission of insulating materials between layers is very slow. The internal heating of various electronic equipment and power supply equipment cannot be eliminated in time, resulting in the high-speed failure of components.And the metal core PCB has good heat dissipation, the metal core heat capacity is large, high thermal conductivity, can quickly dissipate the heat inside the board, if the metal core is connected with the chassis and the external radiator heat dissipation effect is better. Due to the use of metal core PCB in electronic equipment and communication system, the fan in the equipment can be saved, the volume of the equipment is greatly reduced, and the efficiency is improved. It is especially suitable for electronic equipment with closed case.
2. Thermal expansibility
Expansion by heat and contraction by cold are the general characters of matter, and the coefficient of thermal expansion of different matter is different.The thermal expansion coefficient of PCB is anisotropic. In the direction of xY axis, the thermal expansion coefficient of PCB CTE is 13×10-6 ~ 18×10-6 / ℃, and in the direction of plate thickness (z-axis), it is 80×10-6 ~ 90×10-6 / ℃, while the CTE of copper is 16.8×10-6 / ℃, and the CTE of flake ceramic body is 6×10-6 / ℃.It can be seen from these data that there is a big difference between the metallized hole wall of PCB and the connected insulation substrate in the CTE of z-axis. If the generated heat cannot be eliminated in time, the heat expansion and cold shrinkage will easily cause the metallized hole wall coating to crack or disconnect.When welding the ceramic chip carrier device on PCB, due to the difference between the device and the PCB material CTE, long-term stress will lead to fatigue fracture of the solder joint.
The thermal expansion rate of metal core PCB is small, and its size is more stable with the change of temperature than that of insulation PCB.Aluminum-based PCB and aluminum-based sandwich PCB, heated from 30℃ to 140 ~ 150℃, have a size change of only 2.5% ~ 3.0%, which can meet the welding reliability requirements of ceramic chip carrier devices.
3. Magnetic shielding
Metal core PCB also has shielding effect, especially CIC core board has good anti-electromagnetic interference performance, can not only replace the radiator and other parts, can effectively reduce the area of PCB, and has the role of electromagnetic shielding, can improve the electromagnetic compatibility of products, reduce the production cost.Several kinds of commonly used
USES and characteristics of metal core substrates:
Copper base – good thermal conductivity for heat conduction and electromagnetic screen shots, but high quality and expensive.
Iron – anti – electromagnetic interference, the best shielding performance, but poor heat dissipation, cheap price.
Aluminum – good thermal conductivity, light weight, electromagnetic shielding is also good.
Metal base type
Commonly used metal core foils are aluminum core, iron core (including silicon steel), copper core and CIC
1. Aluminum base material
The most commonly used aluminum base materials for manufacturing metal core PCB are LF, L4M and LY12, which require tensile strength of 294N/mm.
The elongation rate is 5%, and the general thickness is 1mm, 1.6mm, 2mm and 3.2mm respectively.Generally, the aluminum layer thickness of aluminum-based PCB used in communication power supply is 140um, and copper foil is attached above and below.
2. Copper substrate
The tensile strength of the commonly used copper substrate is 245 ~ 313.6n/mm2, the elongation is 12%, and the general thickness is 1mm, 1.6mm, 2mm, 2.36mm and 3.2mm.
3. Iron based substrates
Usually used in the production of cold-rolled rolled steel plate, belong to the low carbon steel, the thickness of 1mm, 2.3mm two, or the use of phosphoric iron base thickness of 0.5mm, 0.8mm, 1.0mm three.
4. The copper foil
The back of the copper foil is chemically oxidized and coated with zinc and brass to increase its peel strength.The thickness of copper foil is usually 17.5um, 35um, 75um and 140um.
The above is about the metal circuit board characteristics and substrate detailed introduction, we specialize in the production of metal PCB, welcome to consult.