Common Issues in PCB Production and Solutions
Issue 1: Black-and-White Streaks on Photosensitive Solder Mask
One common problem encountered in PCB production is the presence of black-and-white streaks or dust on the photosensitive solder mask after development. This residue can be easily wiped off with dust-free paper but often indicates incomplete development.
The main cause of this issue is insufficient baking time for the photosensitive black-and-white oil and low exposure energy, preventing the bottom layer from fully curing. To solve this problem, increase the pre-bake time to 75°C ± 5°C for 40 to 50 minutes. Adjust the exposure conditions to achieve clean results without residue.
Issue 2: Oil Residue in Holes After Printing Solder Mask
Another common issue in PCB production is the presence of oil residue in holes after printing solder mask oil. This problem occurs due to poor control of the silk screen during printing, leading to excessive oil entering the holes and causing blockages.
To address this issue, ensure proper control of the silk screen to prevent excess oil from entering the holes. If oil residue remains, consider returning the board to 75°C for 10 minutes before re-developing to achieve complete cleaning.
Preventing Oil Contamination in PCB Holes
Proper control of the printer is essential to prevent excessive oil from entering the holes during PCB manufacturing. If oil residue remains in the hole after development, consider re-baking and re-development as possible solutions. It is advisable to avoid continuing the development process or using caustic soda directly to re-foam, as this may result in wastage.
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