In the PCB solder mask process, sometimes we will have some production problems, today we will be part of the statistical problems and solutions for reference.
| Problem | Causes | Improvement Measures |
| Printing White Spots | Printing issues | Use a matched thinner. |
| Dissolution of screen sealing tape | Switch to using white paper for sealing the screen. | |
| Phosphor Screen Adhesion | Ink not baked dry | Check the degree of ink drying. |
| Over-vacuum | Check the vacuum system (consider not using air guides). | |
| Poor Exposure | Inadequate vacuum | Check the vacuum system. |
| Inappropriate exposure energy | Adjust to suitable exposure energy. | |
| Exposure machine temperature too high | Check the exposure machine temperature (below 26°C). | |
| Ink Not Baked Dry | Poor oven ventilation | Check the oven ventilation condition. |
| Oven temperature insufficient | Measure the actual oven temperature to see if it meets the product requirement. | |
| Not enough thinner used | Increase the thinner and ensure thorough dilution. | |
| Thinner dries too slowly | Use a matched thinner. | |
| Ink layer too thick | Adjust the ink thickness appropriately. | |
| Incomplete Development | Long dwell time after printing | Control the dwell time within 24 hours. |
| Ink exposure before development | Work in a darkroom before development (wrap fluorescent lights with yellow paper). | |
| Insufficient developer solution | Check the concentration and temperature of the developer solution. | |
| Development time too short | Extend the development time. | |
| Overexposure | Adjust the exposure energy. | |
| Overbaking of ink | Adjust the baking parameters, avoid over-baking. | |
| Inadequate ink stirring | Stir the ink evenly before printing. | |
| Thinner mismatched | Use a matched thinner. | |
| Overd evelopment (Over Etching) | High concentration and temperature of developer | Reduce the concentration and temperature of the developer. |
| Excessive development time | Shorten the development time. | |
| Insufficient exposure energy | Increase exposure energy. | |
| High pressure during development | Lower the development water pressure. | |
| Inadequate ink stirring | Stir the ink evenly before printing. | |
| Ink not baked dry | Adjust baking parameters, refer to the problem "Ink Not Baked Dry". | |
| Solder Mask Bridge Breaking | Insufficient exposure energy | Increase exposure energy. |
| Substrate not properly treated | Check the treatment process. | |
| Excessive development and rinse pressure | Check the development and rinse pressure. |
More FQA will show in the next news.
