Specifications for the manufacture of aluminum base pcb

The aluminum boards produced by PCB manufacturers are mostly used for LED lamps. What are the specifications for the production of aluminum base board in the production process?

Aluminum boards produced by aluminum board manufacturers are often used in power devices, and the power density is large, so the copper foil is relatively thick. If a 3 oz or more copper foil  is used, the etching process of the thick copper foil requires engineering line width compensation, otherwise, the line width after etching will be excessive. The surface of the aluminum boards produced by the aluminum board manufacturer must be protected with a protective film in advance during the PCB processing. Otherwise, some chemicals may erode the aluminum base board surface, resulting in damage to the appearance. Moreover, the protective film is easily scratched, causing a gap, which requires that the entire PCB processing process must be inserted.

Manufacturers may have many different difficulties in the production of aluminum base boards:

First, aluminum pcb manufacturers use mechanical processing to produce. After the aluminum board is drilled, no burrs are allowed on the edge of the hole, because the burr will affect the withstand voltage test. The aluminum substrate milling process is very difficult. The punching shape requires the use of advanced molds, which are very skillful in making molds and one of the difficulties in producing aluminum substrates. After the shape is punched, the edge requirements are very neat, without any burrs, and do not hurt the solder mask on the edge of the board. Usually, the military model is used, the hole is punched from the line, the shape is punched from the aluminum surface, and the force is the upper cut and the pull down when the circuit board is punched, and so on. After punching the shape, the board warpage should be less than 0.5%.

Second, the manufacturer is not allowed to wipe the aluminum base in the entire aluminum substrate production process. The surface of the aluminum base is touched by hand, or the surface is discolored and blackened by certain chemicals. This is absolutely unacceptable. Some customers who re-polished the aluminum surface do not accept it, so the whole process is not scratched or touched. Aluminum base is one of the difficulties in producing aluminum pcb. Some enterprises use passivation technology, and some put protective films on the front and back of hot air leveling (HASL). 

Third, the manufacturer is testing the aluminum pcbs under high voltage. The communication power supply aluminum pcb requires 100% high voltage test. Some customers require DC power, some require AC power, voltage requirements are 1500V, 1600V, time is 5 seconds, 10 seconds, 100% printed board is tested. Dirty objects, holes and aluminum-based edge burrs, line serrations, and any other bit of insulation on the board will cause high-voltage test fire, leakage, and breakdown. The pressure test boards were layered and foamed , which are rejected.