How to reduce wave solder slag

The wave solder slag is fiercer than the tiger. If you don't find a solution in time, it will cause a lot of cost waste. What about wave soldering so much tin slag? If you want to solve it, you need to know the reason why the wave soldering slag is much. There are many reasons for the wave solder slag. The main reason for the generation of tin slag by wave soldering is that too much impurity in the wave solder and improper operation result in the formation of tin slag (tofu slag). The following GUS wave soldering will give you a detailed explanation of the causes of these two wave solder slag phenomenon.

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. The copper content and iron content exceeding the standard are the main reasons for the formation of slag. The circuit board is made of copper. Most of the electronic feet are made of iron. Copper and iron are more or less in the operation. The elements fall into the tin furnace and lead to excessive copper and iron over time. When copper is more than 0.8% and iron is more than 0.05%, a large amount of tin slag is generated, which affects the tin defect on the circuit board.

2. The operating temperature of the wave furnace is too high. Too high a temperature is also a cause of excessive slag. Excessive temperature will make copper and iron elements more likely to exceed the standard.

3, the usual cleaning furnace is also very critical, there is no clear furnace for a long time, the impurities in the furnace is high, which is one of the reasons for excessive tin slag.

Solution:

1. Regularly test the tin in the peak 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 peak furnace tin is used for about one month.

2. Control the operating temperature of the wave furnace (about 260-275 degrees Celsius), check the accuracy of the peak furnace temperature meter regularly, and repair it immediately. The flux should be of good quality. If the flux is not good, it will not be Work around 260-275 degrees Celsius.

3. Spot check of welding materials, chemical analysis of tin and tin samples in tin furnace, test whether the composition and impurities have obvious changes, the current welding material manufacturers are mixed, many manufacturers in order to save costs, using secondary recovery of tin residue, welding quality The inferior effect is also one of the important reasons for the large amount of tin slag.

Second, the cause of the wave soldering to produce semi-tin oxide (tofu dross)

4. At present, some of the wave furnaces on the market are not ideally designed. The peaks are too high, the peaks are too wide, the double peak furnaces are too close, and the rotary pump is used. When the peak is too high and the solder falls off the peak, the temperature drop is relatively large. The solder mixes the air into the tin furnace to cause oxidation and semi-dissolution, resulting in the generation of tin slag. The rotary pump did not take precautions, and the tin slag was continuously pressed into the furnace, and the chain reaction of the loop was added with the slag.

5. The temperature of wave soldering is generally controlled to be relatively low, generally 280 ° C ± 5 ° C (for lead-free SN-CU 0.7 tin bars), 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 caused too much tin slag.

6. The larger the contact area of molten tin with air, the more tin slag is. If the molten tin that flows out falls directly into the tin furnace, it is easy to bring in air into the molten tin to combine tin with air to cause tin oxide.

7. Is there any time to clean the dross, so that the solder that falls off the peak can enter the furnace as soon as possible, instead of staying on the dross, the uneven heat will cause too much dross.

Solution:

1. Check the tin slag, check whether the tin furnace has a certain amount of tin slag before opening the operation, and clean the tin slag left before the last work, especially the peak motor area and the peak flow channel area.

2. The amount of tin in the tin furnace should be checked. The amount of tin in the furnace should be close to 0.5-1cm of the furnace surface when stopping the wave. If the amount of tin is small, the contact area with air is large, the probability of oxidation is also large, and the peak of the waterfall falls. As for the big, the impact force of liquid tin also becomes larger, the torrents roll, and the amount of dross formed will be more! It is recommended to add tin bars to the tin furnace immediately.

3. Tin furnace temperature check, when the working temperature is low, hot tin will easily form temporary non-melt accumulation when flowing back from the nozzle. It is recommended that the customer adjust the working temperature of the tin furnace to a higher extent within the allowable range of the product.

4. It is recommended that the operator regularly slag, and the slag must be smashed before going to work every day. When the slag is used, it is not necessary to take the board. The furnace temperature is raised by 10 °C (actual temperature) and then slag is used. It is better to use a small amount of reducing powder when slag is used. Accelerate the separation of tin from slag, which will significantly reduce the amount of slag.

If it is difficult to completely solve the wave soldering dross, we can minimize the wave soldering dross. If you want to reduce the wave soldering dross in addition to the above methods. There is also a wave soldering equipment itself is the key, if you can buy the provincial tin energy-saving wave soldering is the best. GUS wave soldering has been developed through more than ten years of research and development. The tin-saving energy-saving wave soldering has been widely praised by users of wave soldering.

GUS Technology has 20 years of SMT professional manufacturing experience and has trained more than 1,000 technicians and trusted Chinese suppliers in more than 50 countries around the world;

For more product technology, please contact:

Kiman chen

WeChat application: 15711997565

Email: [email protected]

Shenzhen GUS Technology Co., Ltd.

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