How to judge whether there is faulty soldering of components? False soldering detection of electronic components

Date：2022-05-18 15:43:56Views：1289

False welding and false welding reduce the reliability of products, cause unnecessary maintenance to the production process, increase the production cost, reduce the production efficiency, cause great quality and safety hazards to the products that have left the factory, increase the after-sales maintenance cost, increase the mistrust of customers, reduce orders and affect the image of the company. How to judge whether there is faulty soldering of components? What are the general reasons for the faulty soldering of components? In order to help you have an in-depth understanding, the following contents are sorted out by Chuangxin testing network for your reference.

Common types of false soldering

1. The false solder joint occurs in the middle of the solder joint

This kind of phenomenon often occurs around components with high working temperature. The main reason is that the amount of tin used at the solder joint is relatively small. The welding temperature is too high (Accelerated oxidation) or too low, resulting in poor welding quality. There will be a circle of obvious collapse around the solder joint, and the solder joint is not smooth, and the color of the solder joint is dark gray. Therefore, it is relatively easy to find.

2. The false soldering position is between the solder joint and the pad

The reason for this phenomenon is that although the component pins are handled well, the surface of the copper clad pad of the circuit board is not handled well, resulting in insufficient tin during welding. This kind of false soldering phenomenon is not easy to find because it is hidden under the solder joint.

3. The solder joint is between the component pin and the solder joint

The main reason is that the component pins have not been well treated, resulting in the poor fusion between the pins and solder joints. After a long time, the oxidation phenomenon of component pins intensifies, resulting in poor contact between on and off.

Causes of false soldering

1. Defective pad design;

2. Poor reducibility or insufficient amount of flux;

3. The surface of the welded part is not cleaned in advance and the tinning is not firm;

4. The temperature of the soldering iron head is too high or too low, and there is an oxide layer on the surface;

5. The welding time is too long or too short, which is not well mastered;

6. When the solder has not solidified during welding, the welding elements are loose;

7. Oxidation of component pins;

8. Poor solder quality.

Methods to solve false welding

1. Moisture proof storage of components:

If the components are placed in the air for too long, it will lead to moisture absorption and oxidation of the components, resulting in the failure of the components to fully remove the oxide during the welding process, resulting in false welding and false welding defects. Therefore, PCBA processing plants will be equipped with ovens, which can bake components with moisture during welding and replace oxidized components.

2. Select well-known brand solder paste:

The defects of false soldering and false soldering in the process of PCBA welding are closely related to the quality of solder paste.

3. Adjust printing parameters:

Most of the problems of false soldering and false soldering are due to the lack of tin. In the printing process, adjust the pressure of the scraper and select the appropriate steel mesh. The opening of the steel mesh should not be too small to avoid the situation of too little tin.

4. Adjust reflow temperature curve:

During the reflow welder procedure, the welding time shall be well controlled. If the time in the preheating area is not enough, the flux cannot be fully activated and the surface oxide of the welding joint can be removed. If the time in the welding area is too long or too short, false welding and false welding will be caused.

5. Select appropriate testing equipment:

Select AOI detection equipment or X-ray detection equipment. When X-ray detection equipment can detect the parts of circuit board false welding, circuit board cavity and circuit board fracture by detecting the difference of ray intensity of penetrating objects, detect the welding quality and reduce the outflow of false welding and false welding defective products.

This article can only lead you to have a preliminary understanding of the false soldering detection of electronic components. I hope it will be of some help to you. At the same time, it needs to be summarized constantly, so as to improve professional skills. You are also welcome to discuss some knowledge points of this article.