Sep. 11, 2019
PCBA board surface tin beads size acceptable standard shared by electric circuit board assembly manufacturer.
Acceptable standards for tin beads:
1. The diameter of the tin bead shall not exceed 0.13mm.
2. The number of tin beads with a diameter of 0.05mm-0.13mm in the range of 600mm2 shall not exceed 5 (single side).
3. The number of tin beads below 0.05 in diameter is not required.
4. All tin beads must be bound by flux and cannot be moved (the flux is judged to be bound when it is sealed to more than 1/2 of the height of the tin bead).
5. In printed circuit board fabrication, Tin beads do not reduce the electrical gap of conductors of different networks to less than 0.13mm.
Note: special control areas are excluded.
Standard for rejection of tin beads:
Any non-conformity of the receiving standard shall be deemed as rejection.
1. Special control area: tin beads visible under a 20x microscope are not allowed within 1mm around the capacitor pads on the differential signal line at the goldfinger end
2. The presence of tin beads itself represents the warning of the process, PCBA processing manufacturer should continue to improve the process, so that the occurrence of tin beads to the minimum.
PCBA appearance inspection standard is the most basic standard for acceptance of electronic products. According to different requirements of different products and customers, the acceptable requirements for tin beads will be different. Generally, the standard is determined based on national standards and combined with the requirements of customers.