The difference between single-sided circuit boards and double-sided circuit boards is the number of copper layers. Popular science: double-sided circuit boards have copper on both sides of the circuit board, which can be connected through vias. However, there is only one layer of copper on one side, which can only be used for simple circuits, and the holes made can only be used for plug-in connections.
The technical requirements for double-sided circuit boards are that the wiring density becomes larger, the aperture is smaller, and the aperture of the metallized hole becomes smaller and smaller. The quality of the metallized holes on which the layer-to-layer interconnection relies is directly related to the reliability of the printed board.
With the shrinking of the pore size, the debris that did not affect the larger pore size, such as brush debris and volcanic ash, once left in the small hole will cause the electroless copper and electroplating to lose its effect, and there will be holes without copper and become holes. The deadly killer of metallization.
Welding method of double-sided circuit board
In order to ensure the reliable conduction effect of the double-sided circuit board, it is recommended to weld the connection holes on the double-sided board with wires or the like (that is, the through-hole part of the metallization process), and cut off the protruding part of the connection line Injury the operator’s hand, this is the preparation for the wiring of the board.
The essentials of double-sided circuit board welding:
For devices that require shaping, they should be processed in accordance with the requirements of the process drawings; that is, they must be shaped first and plug-in
After shaping, the model side of the diode should face up, and there should be no discrepancies in the length of the two pins.
When inserting devices with polarity requirements, pay attention to their polarity not to be reversed. After inserting, roll integrated block components, no matter it is a vertical or horizontal device, there must be no obvious tilt.
The power of the soldering iron used for soldering is between 25~40W. The temperature of the soldering iron tip should be controlled at about 242℃. If the temperature is too high, the tip is easy to “die”, and the solder cannot be melted when the temperature is low. The soldering time should be controlled within 3~4 second.
The formal welding is generally performed according to the welding principle of the device from short to high and from the inside out. The welding time must be mastered. If the time is too long, the device will be burnt, and the copper line on the copper clad board will also be burnt.
Because it is double-sided soldering, a process frame or the like for placing the circuit board should also be made, so as not to squeeze the components underneath.
After the circuit board is soldered, a comprehensive check-in check should be carried out to find out where there is missing insertion and soldering. After confirmation, trim the redundant device pins and the like on the circuit board, and then flow into the next process.
In the specific operation, the relevant process standards should also be strictly followed to ensure the welding quality of the product.
With the rapid development of high technology, electronic products that are closely related to the public are constantly being updated. The public also needs electronic products with high performance, small size and multiple functions, which puts forward new requirements on circuit boards. This is why the double-sided circuit board was born. Due to the wide application of double-sided circuit boards, the manufacture of printed circuit boards has also become lighter, thinner, shorter and smaller.