Welding methods for SMT pick and place machine resistors and capacitors

Tools: Electric soldering iron, soldering iron holder, wet sponge, tweezers, rosin, solder, degreasing cotton, 95% alcohol, patch resistor, capacitor, circuit board, 220V power supply. 1. Preheating: Insert the electric soldering iron into the iron holder, connect the power supply, and preheat the electric soldering iron. 2, The welding method for identifying surface mount resistors and capacitors is roughly the same, and the welding points are also very similar. They are two flat contact points, but there is a white line in the middle of the contact points of the capacitor to distinguish the welding points of the resistors. Surface mount resistors and capacitors have small volumes, some as small as two or three hairs. Resistors are usually black, with corresponding numbers on the back label representing their specifications. There will also be corresponding markings on the circuit board indicating its position. If there is a "R+number" next to the corresponding resistance welding point, it can be welded accordingly. This resistor does not differentiate between positive and negative poles, while surface mount capacitors may not. Surface mount capacitors without positive or negative electrodes are generally small squares, and all four sides can be soldered. Capacitors with positive and negative poles are relatively large, with only one soldering surface. The one marked with a dark straight line on the back is the positive pole, and the soldering point marked with the "C+" number on the circuit board is the soldering point of the capacitor. The end marked with the "+" sign is the positive pole. 3, First, use an electric soldering iron to melt a small amount of solder to one of the soldering points. Then, use tweezers to pick up the surface mount resistor and capacitor and place them on the soldering point. Finally, use an electric soldering iron to melt the solder that has just been applied, so that one end of the resistor and capacitor is soldered first and fixed. Attention: The resistor and capacitor should be placed directly in the middle of the two soldering points. If there is a large deviation, use a soldering iron to melt the solder again and adjust the position of the resistor and capacitor so that they are directly in the middle. 4, First, melt some solder to the tip of the soldering iron, and then click on the other section of the solder joint. 5, After welding resistors and capacitors, observe whether the welding points are qualified and aesthetically pleasing. If it is not aesthetically pleasing, it should be re soldered and a suitable amount of rosin should be applied to make the soldering surface smooth. 6, Clean a cotton ball the size of a mung bean, clamp it with tweezers, and dip it in 95% alcohol to clean the surface of the circuit board with rosin.