How to do PCB Assembly Visual Inspections?

2017-06-24 17:31:28 zhengxiaowei 165

PCB assembly manual inspection is the most primitive method of PCBA quality inspection, only using the eyes and magnifying glass to check the welding of PCBA board circuit and electronic components, such as welding method, wheather the solder joints are bridging, heather false welding or welding is not Integrity. The magnifying glass is the basic tool in the visual inspection, and the metal inserts can be used to check the weld imperfections on the IC leads.

PCB Assembly Visual Inspections

One/The Wire Part

1, Broken wire

2, There are broken or discontinuous phenomena on the wire. The circuit is located at the edge of PAD and can be repaired by less than or equal to 2mm. The circuit is located at a distance greater than 2mm from the PAD or hole and can't be repaired.

3, short circuit

4, Wire depression / indentation

5, Wire dip tin

6, Wire exposed copper

Two/through the hole part

1, Hole broken

2, Parts of the hole with green paint

3, The tin in the hole

4, The hole out of PAD, not maintenance

5, BGA VIA HOLE plug tin, not repairable

Three/Text part

1, Text out of correct space

2, Text color doesn't match, and printed color is wrong

3, Text ghosting

4, Test is Missing

5, Text ink pollution board surface

6, Text is unclear

Four/PAD part

1, Tin pad gap

2, BGA PAD gap

3, Poor solder joints

4, BGA spray tin uneven

5, PAD falls off

6, QFP is not under ink and can not be repaired

7, QFP drops off the ink

8, PAD exposed copper

9, PAD sticky paint or solder resist ink

Five/other parts

1, PCB sandwich separation

2, Board pollution, the board can not have gray pressure, fingerprints, grease, rosin, rubber residue and so on

3, Forming size is too large or too small, the size of the tolerance beyond the recognition of the standard book

4, Thickness, thin or platey

5, Forming burr

With the increase in PCB production and the reduction in trace spacing and the number of components, visual inspection has become increasingly impractical in the PCBA industry. While it will generally be replced by other advanced test methods.

TAG:   PCB Assembly Visual Inspections