The patch processing factory teaches you two welding techniques
First, wire and wire welding skills
There are three basic forms of lap welding, hook welding and wire bonding between wire and wire.
The lap welding attaches the tin-plated wire to another tin-plated wire. This method is the simplest, but the lowest strength and the least reliable. It is only used for temporary wiring during maintenance and debugging or is inconvenient to wind. Welding, hook welding, and some long-term soldering of the plug-in. When welding, it is necessary to pay attention to the fact that the wire cannot be loosened from the start of welding to the solidification of the solder.
Hook welding bends the tin-plated wires into hooks, joins them together and clamps them with pliers for welding. The strength of the hook welding is lower than that of the welding, but the operation is simple and convenient.
Wrought-iron-welded tin-plated wires are wound and then welded. The thickness of the wires is different, and the welding method is different. If the wires are thick and thin, the thin wires can be wound onto the thick wires. If the wires are the same thickness, they can be twisted and twisted. The method of tightening. The specific winding method is shown in Figures a and b. The reliability of the welding is the highest, so the welding method is generally used in the welding of wires and wires.
The connection between the wires is mainly based on the welding, and the steps of the welding are as follows
1) Remove the wire from the insulation cover of a certain length as required;
2) pre-welding the wire;
3) Put the wire on a heat-shrinkable tube of suitable diameter;
4) stranding two or more wires and welding them;
5) Heat the shrink tube on the heat, and fix the heat shrink tube to the joint of the wire after cooling.
Class 3 components to be distinguished during desoldering
Second, the desoldering skills
1. For components with few smt component pins, such as resistors, capacitors, diodes, and triodes, first tin the solder on one of the pads on the PCB, then use the tweezers to hold the components to the mounting position and hold the board against the left hand. The right hand soldering the pins on the tinned pads with a soldering iron. The left hand tweezers can be loosened, and the remaining wires are soldered with tin wire. It is also easy to remove such components, as long as the soldering iron is used to remove the components. The end is heated at the same time, and after the tin is melted, the component can be removed by gently lifting it.
2. For smt chip processing components with more pins and wider pitch components, a similar method is used. First, tin is plated on one pad, then the left hand is soldered with a tweezers. Well, use tin wire to weld the remaining feet. The disassembly of such components is generally better with a hot air gun. A hand-held hot air gun blows the solder, and the other hand removes the component with a clamp such as a tweezers.
3. For components with high pin density, the soldering step is similar, that is, solder one leg first, then solder the remaining pins with tin wire. The number of pins is relatively large and dense, and the pins are aligned with the pads. It is the key. Usually the pads on the corners are plated with only a small amount of tin. Use a pair of tweezers or hands to align the components with the pads. The sides of the pins are aligned. Press the component on the PCB with a little force. Use a soldering iron. Solder the corresponding pins of the tin pad.
Finally, it is recommended that the high-pin-density components be disassembled mainly with a heat gun, clamp the components with tweezers, blow all the pins back and forth with a heat gun, and lift the components when they are melted. If the components are removed, then blow Whenever possible, do not face the center of the component, and the time should be as short as possible. After the component is removed, use a soldering iron to clean the pad.
The above is the industry consultation provided by smt patch processing factory Shenzhen Pengzexiang Technology Co., Ltd., I hope to help you! Please contact us if necessary: http://www.oem-pcb.com email@example.com