Common bad causes of PCBA welding resistance film

Solder resistance film is a very important coating material in PCBA processing, which can provide medium and mechanical shielding for PCBA plate during and after welding, and prevent solder deposition in this position. Generally, there are two kinds of welding film commonly used in the processing of electronic processing plants, liquid and dry film.

Solder resistance ink is very important in PCBA processing and SMT patch processing, its main role is to protect the circuit board, prevent the conductor from tinning, prevent short circuit caused by moisture and other reasons, prevent the circuit breaker caused by unqualified contact mode in processing, and is one of the reasons to ensure that the PCBA board can be used normally in harsh environments.

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1, pad and through hole connection. In principle, solder resistance should be applied to the wires between the mounting pad and the through holes.

2. The solder resistance design between the pad and the pad, and the solder resistance graphic specifications should conform to the design of the welding end distribution of specific components; If the open window block welding between the pad and the pad causes a short circuit between the pad during welding, the pad and the pad are designed with an independent pin block welding mode, so that there will be no short circuit between the pad during welding.

3, the component solder resistance graphic size is improper, too large solder resistance graphic design, each other will "shield" and lead to open welding, so that the spacing of components is too small.

4. There are holes under the components without welding resistance film, and there are no welding resistance holes under the components. The solder on the holes after over-wave welding may affect the reliability of IC welding, and may also cause defects such as short circuit of the components.

1.Maximum board: 310mm*410mm(SMT);

2. Maximum plate thickness: 3mm;

3. Minimum plate thickness: 0.5mm;

4. Minimum Chip parts: 0201 package or parts above 0.6mm*0.3mm;

5. Maximum mounting parts weight: 150g;

6. Maximum part height: 25mm;

7. Maximum part size: 150mm*150mm;

8. Minimum pin part spacing: 0.3mm;

9. Minimum ball parts (BGA) spacing: 0.3mm;

10. Minimum ball parts (BGA) ball diameter: 0.3mm;

11. Maximum parts mounting accuracy (100QFP) : 25um@IPC;

12. Patch capacity: 3-4 million points/day

1.Strength guarantee

- SMT workshop: with imported SMT machines and a variety of optical inspection equipment, it can produce 4 million points per day. Each process is equipped with QC personnel who can keep a close eye on product quality. - DIP production line: There are two wave welding machines. Among them, there are more than 10 old employees who have worked for more than three years. Skilled workers can weld all kinds of plug-in materials.

2. Quality assurance, high cost performance - high-end equipment can mount precision parts, BGA, QFN, 0201 materials. Proof can be machine paste, also can hand swing.

- Samples and large and small batches can be produced. Proofing starting price 800 yuan, batch starting price 0.008 yuan/point, no start-up fee.

3. Rich experience in SMT and welding of electronic products, stable delivery time and accumulated service for thousands of home appliance subsidiaries, involving SMT processing services for various types of automotive equipment and industrial control motherboards. Products are often exported to Europe and the United States, and the quality is affirmed by new and old customers. - On time delivery, generally delivered within 3-5 days after the board is assembled, small batch expedited can also be shipped on the same day.

4. Strong maintenance ability, perfect after-sales service

- Experienced maintenance engineers, can repair various welding problems caused by bad products, and can ensure the connectivity of each circuit board. - 24-hour customer service staff will be ready to respond and solve your order problems as soon as possible.