Tips for soldering irons, soldering wires and all you need for soldering
Pre-operation check
(1) 3-5 minutes before welding the soldering iron plug into the specified socket, check whether the 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, should immediately report to the administrator, can not be since arbitrarily dismantle the soldering iron, not to mention the direct contact with the iron head with the hand.
(2) has been oxidised uneven or with hooks of the soldering iron head should be updated:
1, can ensure good heat conduction effect;
2, to ensure the quality of the soldered object. If replaced with a new soldering iron tip, heat should be maintained after the paint should be wiped off, immediately add tin maintenance. The cleaning of the soldering iron should be implemented before the soldering operation, if the soldering iron is not used for more than 5 minutes, the power supply needs to be turned off. Sponges should be cleaned clean sponges containing metal particles, or sponges containing sulphur 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 is 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 sulphur 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 parts, 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 of the important means.
3,Soldering essentials
(1) soldering iron tip and the two soldered parts of the contact mode (Figure 6)
Contact position: the soldering iron head should be contacted at the same time to be connected to each other 2 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, the smaller the soldering iron and welding surface 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, which 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 in the soldering iron and the soldered parts between 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 weld a tin point 4 seconds is most appropriate, the maximum does not exceed 8 seconds, usually observe the soldering iron head, 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 you can increase the power of the soldering iron.
