I. Double-sided circuit board characteristics
The difference between single-sided and double-sided circuit boards is the number of layers of copper.
Double-sided circuit board is a circuit board with copper on both sides, which can be connected through holes. And there is only one layer of copper on one side, which can only be used for simple lines, and the holes made can only be used for plug-in but not for conduction.
The technical requirements of the double-sided circuit board are the wiring density, the aperture is smaller, and the aperture of the metallized hole is smaller and smaller. Layer to layer interconnection depends on the quality of the metallized hole, directly related to the PCB reliability.
With the reduction of aperture, the original has no effect on the larger aperture debris, such as brush debris, volcanic ash, once left in the hole inside, will make the chemical precipitation of copper, copper plating lost effect, there is no copper hole, become a fatal killer of hole metallization.
II. Double-sided circuit board in order to ensure that the double-sided circuit has a reliable conductive effect, should first use wires and so on welding the connection hole on the double panel (that is, the metallization process through the hole part), and cut the connection line tip protruding part, so as not to hurt the operator’s hand, this is the board of wiring preparation.
III. Reflow oven welding essentials:
1. Process processing shall be carried out according to the requirements of the process drawings for the devices requiring shaping; That is, after the first plastic plug-in.
2. After shaping, the model face of the diode should be up, and the length of the two pins should not be inconsistent.
3. When the device with polarity requirements is inserted, pay attention to the polarity shall not be inserted back, and the roller integrated block components, after insertion, whether vertical or recumbent device, shall not have obvious tilt.
4. The power of the electric iron used for welding is between 25~40W, the temperature of the electric iron head should be controlled at about 242 deG C, the temperature is too high the head is easy to “die”, the temperature is too low to melt the solder, the welding time is controlled in 3~4 seconds.
5. Formal welding in accordance with the device from high to high, from the inside to the outside of the welding principle to operate, welding time to master, too long time will be hot device bad, will also be hot copper coated wire on the copper coated plate.
6. Because it is double-sided welding, so it should also make a process frame to place the circuit board, so as not to press the device below.
7. after the completion of circuit board welding should be carried out a comprehensive check on the marking type, check the leakage of welding place, confirm the circuit board after the redundant device pin pruning, after flowing into the next process.
8. In the specific operation, should also strictly follow the relevant process standards to operate, to ensure the welding quality of products.
With the rapid development of high technology, electronic products closely related to the public are constantly updated, the public also need high performance, small size, multi-function electronic products, which put forward new requirements for the circuit board.
Post time: Sep-03-2021