How to choose the right soldering iron
Generally, when users choose a soldering iron, they will first consider the power (Watt) of the soldering iron to measure the performance of the soldering iron. They think that the higher the power, the better. In fact, this concept is incorrect. The performance of the soldering iron depends on many aspects, mainly as follows:
1) Heat/temperature supply: a) heat recovery speed; b) heat capacity; c) temperature accuracy;
2) Management of welding temperature;
3) Security: a) for electronic components; b) for users;
4) Whether it complies with lead-free soldering.
Due to the variety of electronic soldering jobs, not every soldering job needs to have all the features and capabilities of a soldering iron. If you don't know how to choose a soldering iron, you may choose a soldering iron that does not meet your requirements or the price-performance ratio exceeds the standard; sometimes you may choose a soldering iron that is too simple and fail to complete the soldering work effectively. Soldering is actually a simple job, and the choice should make a difference. If you want to choose a soldering iron properly, you must first know what kind of soldering job you want to complete. The following introduction to the performance of the soldering iron guides users on how to choose a suitable soldering iron to meet the actual needs of the work.
1. Heat recovery speed
①Explanation of heating speed: When welding a solder joint, the temperature of the solder tip will drop slightly due to the large amount of heat transferred to the solder joint. When the welding is completed and the welding tip leaves the solder joint, the temperature will gradually return to the original temperature. Then the speed of the whole process from the completion of welding to the temperature rising to the original temperature is called "heat recovery speed".
What is the difference between a soldering iron with a fast heat recovery and a slow heat recovery? Especially noticeable during continuous welding. Continuous welding means that when a welding spot is completed, the second welding spot is welded immediately, so that the welding work is carried out continuously. Figures 1 and 2 show the difference between the two. The two pictures show the temperature change of the welding tip over time. The power is turned on from room temperature, and continuous welding starts after the temperature stabilizes. After the work is finished, wait for the temperature to rise back to the set temperature (the horizontal axis represents time, and the vertical axis represents temperature).
When the first welding work is performed, the temperature of the welding tip drops, and when the first welding is completed and the second welding is prepared, the temperature rises. A soldering iron with a slow heating rate, due to the slow heating rate, the temperature may be insufficient after several soldering operations. However, a soldering iron with a high heat recovery rate can maintain a stable temperature output during continuous soldering.
② Coordination of heat recovery speed and work
If you are doing intermittent one or two spot soldering, you can use some soldering irons that don't reheat quickly. However, if you do continuous spot welding (for example, the production line works continuously, you need a soldering iron with a high heat recovery rate. In addition, if you need to use some special soldering tips to drag and weld PLCC, QFP and other chips, because you need to continuously weld the chips on the chip in a short time For multiple solder joints, it is necessary to use a soldering iron with a high heat recovery rate. If you want to use a soldering iron with a low heat recovery rate for continuous soldering, you must use high temperature, but high temperature will damage sensitive electronic components. Use a soldering iron with a high heat recovery rate Low temperature soldering can be used.
PLCC chip welding
Fast reheating enables sufficient welding at low temperature, reduces damage to circuit boards and sensitive electronic components, prolongs the life of welding tips, and increases the efficiency of continuous welding. Rapid reheating reduces large temperature fluctuations during welding, making welding work easy to control.
2. Heat capacity
Welding tips of different sizes have different heat capacities. The larger the welding tip, the greater the heat capacity, and the less heat will be lost during welding. On the contrary, the thinner the welding tip, the smaller the heat capacity, and the more heat will be lost during welding.
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Coordination of heat capacity and work
When choosing a soldering iron, consider the size of the soldering tip. If you use a large soldering tip, you can use a relatively low-temperature soldering iron; if you use a small soldering tip, you need to use a relatively high-temperature soldering iron. If the soldering work needs to change the size of the soldering tip, you should use a soldering iron with temperature adjustment. Regardless of the size of the soldering tip, you only need to use the temperature adjustment function to cooperate. Small welding tips need to use high temperature welding to provide enough heat because of their relatively small heat capacity. However, high temperature will easily oxidize the welding tips and reduce the life of the welding tips. Therefore, when using small welding tips, pay special attention to maintenance and clean the welding tips frequently. Tsui, turn down the temperature immediately after use.
3. Temperature accuracy of welding tip
Nowadays, the electronic components to be soldered are getting smaller and more precise, and the temperature requirements are getting stricter, so the temperature accuracy of the soldering iron is also very important. Many people think that if there is a difference between the set temperature and the actual temperature of the soldering tip, it means that the performance of the soldering iron is faulty or damaged, but this is not the case. The difference between the tip temperature and the actual temperature is mainly affected by two factors, including (1) the size and shape of the solder resistance, and (2) the loss of the tip and heating core.
