Soldering iron soldering wire tips and soldering essentials
Manual welding process:
1、Check before operation
(1) 3-5 minutes before welding the soldering iron plug into the specified socket, check whether the soldering iron is hot, such as found not hot, first check whether the socket is plugged in, such as plugged in, if it is not hot, it should be immediately reported to the administrator, can not be since the arbitrary dismantling of the soldering iron, not to mention the direct contact with the iron head with the hand.
(2) has been oxidized uneven or hooked iron head should be updated:
(1) can ensure good heat conduction effect;
(2) Ensure the quality of the soldered object. If replaced with a new soldering iron tip, heat should be maintained after the paint wiped off, immediately add tin maintenance. The cleaning of the soldering iron should be implemented before the soldering operation, if the iron is not used for more than 5 minutes, the power supply needs to be turned off. Sponge should be cleaned unclean sponge containing metal particles, or sponge containing sulfur will damage the soldering iron head.
(3) check whether the tin sponge water and clean, if no water, please add the right amount of water (the right amount is to press the sponge to the normal half-thickness when there is water seepage, the specific operation is: humidity requirements of the sponge all wet, hold in the palm of your hand, five fingers naturally together can be), the sponge should be cleaned clean sponge does not clean sponges contain metal particles, or sponges containing sulfur will damage the head of the soldering iron.
(4) whether the human body and the soldering iron is reliably grounded, whether the human body is wearing a static electricity ring.
2, welding steps
Soldering iron welding specific operating steps can be divided into five steps, known as the five-step engineering method, to obtain good welding quality must be strictly in accordance with the following figure five operation.
According to the above steps for welding is one of the keys to obtain a good solder joints. In actual production, the most likely to appear a violation of the operating steps of the practice is the soldering iron head is not the first contact with the soldered parts, but the first contact with the solder wire, melted solder drops in the end of the preheated parts of the soldered, so it is easy to produce solder joints soldering, so the soldering iron head must be in contact with the soldered parts, the soldered parts preheating is to prevent the production of soldering is an important means.
3、Soldering essentials
(1) soldering iron tip and the contact mode of the two soldered parts (Figure 6)
Contact position: the soldering iron head should be contacted at the same time to connect each other with the two soldered parts (such as soldering feet and pads), the iron is generally tilted at 45 degrees, should be avoided only with one of the soldered parts in contact. When the two soldered parts heat capacity disparity, should be properly adjusted soldering iron tilt angle, soldering iron and the welding surface of the smaller the tilt angle, so that the heat capacity of the larger soldered parts and the soldering iron to increase the contact area, heat conduction ability to strengthen. Such as LCD pull welding tilt angle of about 30 degrees, welding microphone, motor, horn tilt angle can be about 40 degrees. The two soldered parts can reach the same temperature in the same time, is regarded as the ideal state of heating.
Contact pressure: the soldering iron tip and the soldered parts contact should be slightly pressure, heat conduction is proportional to the size of the pressure applied, but to the surface of the soldered part does not cause damage to the principle.
(2) The supply method of the welding wire
The supply of welding wire should grasp the three essentials, both the supply time, location and quantity.
Supply time: in principle, the soldered parts to reach the melting temperature of the solder is immediately sent on the solder wire.
Supply position: should be between the soldering iron and the soldered parts and as close as possible to the pad.
Supply quantity: should look at the size of the soldered parts and pads, solder cover the pad after the solder is higher than 1/3 of the diameter of the pad can be.
(3) Soldering time and temperature settings
A, the temperature by the actual use of the decision to solder a tin point 4 seconds is most appropriate, the maximum does not exceed 8 seconds, usually observe the head of the soldering iron, when it is purple, the temperature is set too high.
B, general direct electronic materials, the actual temperature of the soldering iron tip is set to (350 ~ 370 degrees); surface mount materials (SMC) materials, the actual temperature of the soldering iron tip is set to (330 ~ 350 degrees)
C, special materials, the need for special settings iron temperature, FPC, LCD connectors, etc. to use silver-containing tin wire, the temperature is generally between 290 degrees to 310 degrees.
D, welding large components feet, the temperature should not exceed 380 degrees, but can increase the power of the soldering iron.
