With the rapid development of high technology, electronic products that are closely related to people are constantly being updated, and people also need electronic products with high performance, small size and multiple functions, which puts forward new requirements for circuit boards. The double sided circuit board was born because of this. Due to the wide application of double sided circuit boards, the manufacture of printed circuit boards has also developed to light, thin, short and small.
Ⅰ. The features of the double-sided circuit board
The difference between a single sided circuit board and a double sided circuit board is the number of layers of copper. The double-sided circuit board has copper on both sides of the circuit board, which can be conducted through the holes and play a connection role. And 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-ins and cannot be connected. The technical requirements of double-sided circuit boards are that the wiring density becomes larger, the aperture is smaller, and the aperture of the metallized hole is getting 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.
Double-sided High TG ENIG Prototype PCB
Ⅱ. The welding method for the double sided circuit board
In order to ensure the reliable conduction effect of the double sided circuit on the double sided circuit board, the connection holes on the double sided circuit board (that is, the through-hole part of the metallization process) should be welded first with wires and the like, and the protruding part of the connecting line tip should be cut off to avoid injuring the operator’s hand, this is the wiring preparation for the board. The double sided circuit board welding essentials:
1. For devices that require shaping, they should be processed according to the requirements of the process drawings; that is, shaping first and then inserting.
2. After shaping, the model side of the diode should face up, and there should be no difference in the length of the two pins.
3. For devices with polarity requirements, it should be noted that the polarity should not be reversed when inserting, and the roller integrated block components, whether vertical or horizontal, should not have obvious inclination after inserting.
4. The power of the electric soldering iron used for soldering is between 25~40W. The temperature of the electric soldering iron head should be controlled at about 242 °C. If the temperature is too high, the head is easy to “die”. When the temperature is low, the solder cannot be melted, and the welding time is controlled within 3 to 4 seconds.
5. During formal welding, generally follow the welding principle of the device from short to high, from the inside to the outside. The welding time should be mastered well. If the time is too long, the device will be scalded, and the copper clad lines on the copper clad plate will also be scalded.
6. Because it is double sided soldering, a process frame for placing the circuit board or the like should also be made, so as not to slant the devices below.
7. After the welding of the double sided circuit board is completed, a comprehensive inspection of the number and seat type should be carried out to check the places where there are leaks and leaks.
8. In the specific operation, the relevant process standards should also be strictly followed to ensure the welding quality of the product.