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PCB visual inspection specification
PCB News
PCB visual inspection specification

PCB visual inspection specification

2021-11-09
View:78
Author:Kavie

One, the line part:


PCB


1, disconnection,
    A, there is a break or discontinuity on the line,
    B, The length of the broken wire on the line exceeds 10mm and cannot be repaired.
    C, The disconnection is near the PAD or the edge of the hole, (the disconnection is at the PAD or the edge is less than or equal to 2mm and can be repaired. The disconnection is greater than 2mm from the PAD or the edge of the hole, and it cannot be repaired.)
    D, The adjacent lines are disconnected side by side and cannot be repaired.
    E. The line gap is broken at the turn, (the distance from the break to the turn is less than or equal to 2mm, and it can be repaired. The turn at the break is greater than 2 mm, and it cannot be repaired.)
2, short circuit,
    A, There is a foreign object between the two wires that causes a short circuit, which can be repaired.
    B. The inner short circuit cannot be repaired.
3, the line gap,
    A. The line gap is less than 20% of the original line width and can be repaired.
4. Line depression & indentation,
    A. The line is uneven, press down the line and it can be repaired.
5, the circuit is tinted,
    A. The circuit is tinned, (the total tinned area is less than or equal to 30 mm2, which can be repaired, and the tinned area is greater than 30 mm2 and cannot be repaired.
6, the line is poorly repaired,
    A, The offset of the compensation line or the specification of the compensation line does not meet the original line size (acceptable if it does not affect the minimum width or spacing)
7, the line exposed copper,
    A, The solder mask on the circuit falls off and can be repaired
8, the line is crooked,
    A, The spacing is smaller than the original spacing or there are notches, which can be repaired
9, the line is stripped,
    A, There has been peeling between the copper layer and the copper layer, and it cannot be repaired.
10. Insufficient line spacing,
    A. It is impossible to reduce the distance between the two lines by more than 30%. Repairable, more than 30% can not be repaired.
11, residual copper,
    A, The distance between the two lines cannot be reduced by more than 30%, and it can be repaired.
    B, The distance between the two lines is reduced by more than 30% and cannot be repaired.
12. Line pollution and oxidation,
    A. Some of the lines are discolored and dark due to oxidation or contamination, and cannot be repaired.
13, the line is scratched,
    A. If the wire is exposed to copper due to scratches, it can be repaired, and if there is no exposed copper, it will not be regarded as scratched.
14, the thread is thin,
    A, The line width is less than 20% of the specified line width and cannot be repaired.

Second, the solder mask part:
1, color difference (standard: upper and lower two levels),
    A, The ink color of the board surface is different from the standard color. You can check the color difference table to determine whether it is within the acceptable range
2. Anti-welding cavitation;
3. Anti-welding exposed copper;
    A, The green paint peels off the exposed copper and can be repaired.
4. Anti-welding scratches;
    A, the solder mask can be repaired if the copper is exposed or the substrate is seen due to scratches
5. Solder mask ON PAD,
    A, The parts tin pad & BGA PAD & ICT PAD are stained with ink and cannot be repaired.
6. Poor repair: the green paint coating area is too large or the repair is incomplete, the length is greater than 30mm, the area is greater than 10mm2 and the diameter is greater than 7mm2; it is not acceptable.
7. There are foreign objects;
    A, There are other foreign objects in the solder mask. Repairable.
8 uneven ink;
    A. There is ink accumulation or unevenness on the board surface, which affects the appearance, and local slight ink accumulation does not require maintenance.
9. VIAHOL of BGA is not filled with ink;
    A, BGA requires 100% ink plugging,
10. The VIA HOLE of CARD BUS is not plugged with ink
    A, The VIAHOLE at the CARD BUS CONNECTOR needs to be 100% plugged. The inspection method is that there is no light through the backlight.
11.VIA HOLE is not plugged;
    A, VIA HOLE requires 95% cold, and the hole inspection method is opaque under backlight
12. Dip tin: no more than 30mm2
13. False exposed copper; repairable
14. Wrong ink color; not repairable

3. Through hole part;
1, hole plug,
    A. Foreign matter in the part hole causes the part hole to be blocked and cannot be repaired.
2, the hole is broken,
    A, The ring hole is broken and the hole cannot be connected up and down, which cannot be repaired.
    B, The dotted hole cannot be repaired.
3. Green paint in the hole of the part,
    A, The part hole is covered by solder resist and white paint residue, which is not repairable
4. NPTH, tin dip in the hole
    A, NPTH holes are made into PHT holes, which can be repaired.
5. Hole lock, not repairable
6, The hole leaks the lock and cannot be repaired.
7, The hole is off, the hole is off the PAD, it can not be repaired.
8, the hole is big, the hole is small,
A, The hole size exceeds the specification error value. It cannot be repaired.
9, BGA's VIA HOLE hole plug tin, can not be repaired.

Fourth, the text part:
1, The text is offset, the text is offset, and the painting is overwritten to the tin pad. It is not repairable.
2, The text color does not match, and the text color is printed incorrectly.
3. Text ghosting, text ghosting is still recognizable and repairable,
4. The text is missing, and the text is not repairable.
5. The text ink stains the board surface, and the text ink stains the board surface, which can be repaired.
6, The text is unclear, the text is unclear, which affects the recognition. It can be repaired.
7, the text is off, there is a 3M600 tape for tensile test, the text is off, and it can be repaired.

Five, the PAD part:
1, the tin pad gap, the tin pad is notched due to scratches or other factors, it can be repaired,
2, BGA PAD gap, the tin pad of the BGA part has gaps and cannot be repaired,
3. Poor optical dots, optical dots spray tin burrs, uneven, uneven or inaccurate alignment caused by paint, causing parts to shift and cannot be repaired,
4, BGA tin spraying is uneven, the thickness of the spraying tin is too thick, and the tin is flat after being pressed by external force, which cannot be repaired.
5. The optical point falls off, and the optical point falls off and cannot be repaired.
6, PAD falls off, PAD fall off can be repaired.
7, QFP is not inked and cannot be repaired,
8. The QFP under the ink drop off, QFP under the ink drop within 3 pieces can be accepted. Otherwise it can not be repaired,
9, Oxidation, PAD is polluted and discolored, repairable,
10. PAD exposed copper, if BGA or QFP PAD exposed copper, it cannot be repaired.
11.The PAD is stained with white paint or solder resist ink, and the PAD is covered with white paint or ink, which can be repaired.

Six, other parts:
1, PCB sandwich separation, white spots, white spots, not repairable,
2, The texture is exposed, there are woven glass weave traces in the board, and it is not repairable if it is greater than or equal to 10mm2.
3. The board surface is contaminated. The board surface must not have dust pressure, fingerprints, oil stains, rosin, glue residue, or other external pollution, which can be repaired.
4. The molding size is too large or too small, and the external dimension tolerance exceeds the approval standard and cannot be repaired.
5. Poor cutting, incomplete forming, no repair,
6, The board thickness, the board is thin, the board thickness exceeds the PCB production specifications, and cannot be repaired,
7, The board is warped, the height of the board is greater than 1.6mm, and it cannot be repaired.
8. Molding burrs, poor molding causes burrs, and the board edges are not flat and can be repaired.

The above is the introduction of PCB visual inspection specifications. Ipcb also provides PCB manufacturers and PCB manufacturing technology.