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How to Prevent Virtual Welding of thumbwheel potentiometer
Date：2018-11-27
Views：487
What is false welding? False welding is false welding spot. These virtual solder joints on the welding foot of thumbwheel potentiometer are interrupted from time to time, and the resulting faults are sometimes absent, and are not easy to find and eliminate. The resistance body of the dial potentiometer needs to be connected by tin soldering to lead out the electrodes. The quality of solder joints will seriously affect the overall quality of the potentiometer. We must pay attention not to produce virtual soldering. Then, how to prevent the virtual welding of thumbwheel potentiometer?
1. Proper amount of tin.
The amount of tin dipped in soldering iron is determined according to the size of solder joint needed, so that solder can encapsulate the solder toughness sufficiently to form a suitable and smooth solder joint. On the contrary, the possibility of virtual soldering of this kind of solder joint is greater. thumbwheel potentiometer with switch may be that the solder is accumulated on it rather than soldered on it. If the amount of tin is insufficient at one time, it can be repaired again, but the soldering iron must be removed after the previous tin is melted together; if the amount of tin is too large at one time, the appropriate amount can be taken away by the soldering iron head.
2. Welding temperature should be appropriate
In order to make the temperature appropriate, the appropriate power of soldering iron should be selected according to the size of potentiometer. When the power of the selected soldering iron is fixed, attention should be paid to controlling the length of heating time.
When solder of thumbwheel potentiometer with switch is automatically scattered from the soldering head to the solder, the heating time is sufficient. At this time, quickly remove the soldering head, leaving a smooth solder joint at the solder joint. If after removing the soldering iron, there is little tin left or no tin left at the solder joint, it means that the heating time is too short, the temperature is not enough or the solder is too dirty. If before removing the soldering iron, the solder will flow downward, which indicates that the heating time is too long and the temperature is too high. Generally, the temperature control of soldering head is the best welding temperature when flux melts faster without smoking.
3. Welding time should be appropriate
The proper use of welding time is also an important part of welding technology. If it is the welding of printed circuit board, it is generally appropriate to use 2-3S. The welding time is too long, the flux in the solder is completely volatilized, losing the role of welding aids, making the surface of the solder joint oxidized, resulting in defects such as rough, blackened, dull, burred or flowing surface of the solder joint. At the same time, the copper foil of components or printed circuit boards can be easily scalded if the welding time is too long and the temperature is too high. If the welding time is too short to reach the welding temperature, the solder can not be fully melted, affecting the wettability of flux, easy to cause virtual welding.
4. Keep the iron head clean
Because the electric soldering headof thumbwheel potentiometer with switch is in high temperature for a long time, its surface is easy to oxidize or burn, which makes the thermal conductivity of the soldering head worse and affects the welding quality. Therefore, the impurities on the iron head can be wiped with wet cloth or sponge. When the temperature is too high, the plug can be temporarily unplugged or dipped in rosin to cool down, so that tin can be hanging on the iron head at any time.
5. Do not touch the solder joint during solidification
Before solidification of solder joint, even if thumbwheel potentiometer has a small vibration, the solder joint will be deformed and virtual soldering will be caused. Therefore, the solder joint should be fixed before the soldering head is withdrawn, such as clamping with tweezers, or blowing with the mouth quickly after the soldering head is withdrawn. The purpose of these methods is to shorten solidification time of solder joint.
1. Proper amount of tin.
The amount of tin dipped in soldering iron is determined according to the size of solder joint needed, so that solder can encapsulate the solder toughness sufficiently to form a suitable and smooth solder joint. On the contrary, the possibility of virtual soldering of this kind of solder joint is greater. thumbwheel potentiometer with switch may be that the solder is accumulated on it rather than soldered on it. If the amount of tin is insufficient at one time, it can be repaired again, but the soldering iron must be removed after the previous tin is melted together; if the amount of tin is too large at one time, the appropriate amount can be taken away by the soldering iron head.
2. Welding temperature should be appropriate
In order to make the temperature appropriate, the appropriate power of soldering iron should be selected according to the size of potentiometer. When the power of the selected soldering iron is fixed, attention should be paid to controlling the length of heating time.
When solder of thumbwheel potentiometer with switch is automatically scattered from the soldering head to the solder, the heating time is sufficient. At this time, quickly remove the soldering head, leaving a smooth solder joint at the solder joint. If after removing the soldering iron, there is little tin left or no tin left at the solder joint, it means that the heating time is too short, the temperature is not enough or the solder is too dirty. If before removing the soldering iron, the solder will flow downward, which indicates that the heating time is too long and the temperature is too high. Generally, the temperature control of soldering head is the best welding temperature when flux melts faster without smoking.
3. Welding time should be appropriate
The proper use of welding time is also an important part of welding technology. If it is the welding of printed circuit board, it is generally appropriate to use 2-3S. The welding time is too long, the flux in the solder is completely volatilized, losing the role of welding aids, making the surface of the solder joint oxidized, resulting in defects such as rough, blackened, dull, burred or flowing surface of the solder joint. At the same time, the copper foil of components or printed circuit boards can be easily scalded if the welding time is too long and the temperature is too high. If the welding time is too short to reach the welding temperature, the solder can not be fully melted, affecting the wettability of flux, easy to cause virtual welding.
4. Keep the iron head clean
Because the electric soldering headof thumbwheel potentiometer with switch is in high temperature for a long time, its surface is easy to oxidize or burn, which makes the thermal conductivity of the soldering head worse and affects the welding quality. Therefore, the impurities on the iron head can be wiped with wet cloth or sponge. When the temperature is too high, the plug can be temporarily unplugged or dipped in rosin to cool down, so that tin can be hanging on the iron head at any time.
5. Do not touch the solder joint during solidification
Before solidification of solder joint, even if thumbwheel potentiometer has a small vibration, the solder joint will be deformed and virtual soldering will be caused. Therefore, the solder joint should be fixed before the soldering head is withdrawn, such as clamping with tweezers, or blowing with the mouth quickly after the soldering head is withdrawn. The purpose of these methods is to shorten solidification time of solder joint.