Welding Iron Wire Welding Tips and Welding Accessories
Manual welding process:
1. Inspection before operation
(1) Insert the soldering iron plug into the specified socket 3-5 minutes before welding, and check whether the soldering iron is hot. If it is not hot, first check whether the socket is plugged in properly. If it is plugged in, if it is still not hot, call the administrator immediately. Report, do not take apart the soldering iron at will, let alone touch the soldering iron head directly with your hands.
(2) Soldering tips that are oxidized, uneven or have hooks should be replaced:
1) Can ensure good heat conduction effect;
2) Ensure the quality of the objects to be welded. If a new soldering iron tip is replaced, the maintenance paint should be wiped off after being heated and tin maintenance should be applied immediately. The soldering iron should be cleaned before soldering. If the soldering iron is not used for more than 5 minutes, the power must be turned off. The sponge must be cleaned. Dirty sponges containing metal particles or sulfur-containing sponges will damage the soldering iron tip.
3) Check whether the desoldering sponge has water and is clean. If there is no water, please add an appropriate amount of water (appropriate amount means water seeps out when the sponge is pressed to half its normal thickness. The specific operation is: after the humidity requirement is that the sponge is completely wet, Hold it in the palm of your hand and close your fingers naturally). The sponge should be cleaned. Dirty sponges containing metal particles or sulfur-containing sponges will damage the soldering iron head.
4) Whether the human body and the soldering iron are reliably grounded, and whether the human body wears an electrostatic ring.
2. Welding steps
The specific operation steps of soldering iron welding can be divided into five steps, called the five-step engineering method. To obtain good welding quality, you must strictly follow the five operations as shown in the figure.
Soldering according to the above steps is one of the keys to getting a good solder joint. In actual production, one of the most common violations of operating procedures is that the soldering iron tip does not contact the soldered part first, but first contacts the solder wire. The molten solder drips on the soldered part that has not yet been preheated. This can easily cause false soldering of solder joints, so the soldering iron tip must be in contact with the parts to be welded. Preheating the parts to be welded is an important means to prevent false soldering.
3. Welding essentials
(1) The contact method between the soldering iron tip and the two parts to be welded
Contact position: The soldering iron tip should contact two parts to be welded (such as solder legs and pads) at the same time. The soldering iron is generally tilted at 45 degrees and should avoid contact with only one of the parts to be welded. When the heat capacity of two parts to be welded is very different, the tilt angle of the soldering iron should be adjusted appropriately. The smaller the tilt angle between the soldering iron and the welding surface, the greater the contact area between the part to be welded and the soldering iron with the larger heat capacity, and the stronger the heat conduction capability. For example, the inclination angle is about 30 degrees when welding LCDs, and the inclination angle when welding microphones, motors, speakers, etc. can be about 40 degrees. The two parts to be welded can reach the same temperature in the same time, which is considered an ideal heating state.
Contact pressure: When the soldering iron tip is in contact with the workpiece to be welded, a slight pressure should be applied. The strength of heat conduction is proportional to the amount of pressure applied, but the principle is to not cause damage to the surface of the workpiece to be welded.
(2) Supply method of welding wire
The supply of welding wire should control three key points, namely supply time, location and quantity.
Supply time: In principle, the solder wire is supplied immediately when the temperature of the workpiece to be welded reaches the melting temperature of the solder.
Supply position: should be between the soldering iron and the parts to be soldered and as close to the soldering pad as possible.
Supply quantity: It should depend on the size of the parts to be welded and the pad. After the solder covers the pad, the solder should be higher than 1/3 of the diameter of the pad.
(3) Welding time and temperature settings
A. The temperature is determined by actual use. It is most suitable to solder a tin point for 4 seconds, and the maximum should not exceed 8 seconds. Observe the soldering iron tip at ordinary times. When it turns purple, the temperature is set too high.
B. For general direct-plug electronic materials, set the actual temperature of the soldering iron tip to (350~370 degrees); for surface mount materials (SMC), set the actual temperature of the soldering iron tip to (330~350 degrees)
C. Special materials require special setting of soldering iron temperature. FPC, LCD connectors, etc. must use silver-containing tin wire, and the temperature is generally between 290 degrees and 310 degrees.
D. When welding large component pins, the temperature should not exceed 380 degrees, but the power of the soldering iron can be increased.
