Wave soldering will produce a lot of tin dross, how to reduce wave solder dross?
Wave soldering will produce a lot of tin dross. If you don't find a solution in time, it will cause a lot of waste of cost.
If you want to solve it, you need to know the reason for the wave soldering dross to know how to solve the wave soldering dross. There are many reasons for the wave soldering dross.
The main reason for wave soldering to produce tin slag is that the wave solder has too many impurities and improper operation produces semi-tin oxide slag.
JOYSMT specifically analyzes what causes these two wave solder slag phenomena.
1. Causes of tin impurity content exceeding the standard tin slag after wave soldering
(1) The copper content and trace elements of the peak tin furnace tin exceed the standard.
Among them, excessive copper content and iron content are the main reasons for the formation of more slag.
The circuit boards are made of copper, and most of the electronic feet are made of iron.
In the process of operation, more or less copper and iron elements will fall into the tin furnace.
Over time, the copper and iron elements will exceed the standard. When copper is greater than 0.8% and iron is greater than 0.05%,
a large amount of tin slag will be generated. This affects the bad tin on the circuit board.
(2) The operating temperature of the wave crest furnace is too high. Excessive temperature is also the cause of more slag. Excessive temperature will make the copper and iron elements more likely to exceed the standard.
(3) The usual furnace cleaning is also very important. If the furnace is not cleaned for a long time, the impurity content in the furnace is too high, which is also one of the reasons for the excessive tin slag.
Solution:
1) Periodically test the tin in the wave furnace. When the copper content is greater than 0.8% and the iron is greater than 0.05%, the tin in the wave furnace should be replaced. Usually the tin in the wave furnace is about one month.
2) Control the operating temperature of the wave furnace (about 260-275 degrees Celsius), regularly check whether the wave furnace temperature table is accurate, if there is any abnormality, it should be repaired immediately. The flux should be of good quality. If the flux is not good, it will not Operate around 260-275 degrees Celsius.
3) Spot inspection of welding materials, analysis of liquid tin samples in the tin furnace to test whether there are obvious changes in their composition and impurities. At present, welding material manufacturers are mixed, many manufacturers use secondary recovery tin slag to save costs, welding quality Poor effect is also one of the important reasons for the large amount of tin slag.
2. Causes of wave soldering to produce tin oxide (tofu slag tin slag)
3. At present, the design of some wave furnaces on the market is not ideal. The wave peak is too high, the peak table is too wide, the double wave furnace is too close and the rotary pump is used. The wave peak is too high, when the solder falls from the peak , The temperature drop deviation is relatively large, the solder mixed with air rushed into the tin furnace to cause oxidation and semi-dissolution, resulting in the generation of tin slag. The rotary pump did not take good precautions, constantly pressing the tin slag into the furnace, looping The chain reaction and the production of tin slag.
4. The temperature of wave soldering is generally controlled relatively low, generally 280 ℃ ± 5 ℃ (for the lead-free SN-CU0.7 tin bar), and this temperature is the most basic requirement in the solder process The temperature reached, the temperature is too low tin can not achieve a good dissolution, indirectly causing too much dross.
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Automatic tin machine accurately controls the tin position, effectively reducing losses by 10-20%
5. Tin height difference: the larger the contact area between molten tin and air, the more tin dross. If the molten tin sprayed directly falls into the tin furnace, it is easy to bring air into the molten tin to make the tin and air combine to cause tin oxide .
6. Have you cleaned the dross frequently so that the solder falling from the peak can enter the furnace as soon as possible, instead of being left on the dross, uneven heating will also cause excessive dross.
Fully automatic dip welding machine instead of wave soldering 8 hours below 0.8KG
Solution:
1) Check the tin dross, check whether there is a certain amount of tin dross before the tin furnace is opened, and clean up the tin dross left before the last work in a timely manner, especially the peak motor area and the peak flow gate area.
2) Check the amount of tin in the tin furnace. The amount of tin in the furnace should be within 0.5-1.0 cm of the furnace surface when the wave is stopped. If the amount of tin is small, the area of contact with the air is large, the probability of oxidation is also large, and the peak falls. That is, the impact force of liquid tin also becomes greater, and the torrent will roll over, resulting in more tin slag! It is recommended to add tin bars to the tin furnace immediately.
3) Check the temperature of the tin furnace. When the working temperature is low, hot tin will easily form temporary non-melted material when flowing back from the nozzle. It is recommended that the customer increase the working temperature of the tin furnace within the allowable range of the product.
4) It is recommended that the operator slag slag regularly, and slag must be slagged before work every day. When slag slag is removed, the furnace temperature should be increased by 10 degrees Celsius. , Accelerate the separation of tin and slag, which will significantly reduce the amount of slag.
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