Attention ! Always compare current standards. They are often different from each other. Here DIN EN 61191, Part 1 - 4, and IEC 61191, Part 1 - 4, respectively are taken as reference. The assessment of all solder joints is based on the standards stated above.
Description:
Poor solder fillet. In accordance with IEC 61191-3, still acceptable, since the solder fillet fills more than 75% of the through-hole.
Causes/Remedy:
- poor wettability of component
- poor wettability of through-hole
- unsuitable soldering parameter
- pollution of materials to be joined
Source:Microsection
Description:
The solder joint is still acceptable despite disturbed wetting at the contact pin on the left..
Causes/Remedy:
- poor wettability of component
- poor wettability of through-hole
- unsuitable soldering parameter
- pollution of materials to be joined
Source:Microsection
Description:
Example of a solder joint with wetting problems at the component lead (left).No rework necessary though. The solder joint on the right is ideal.
Causes/Remedy:
- poor wettability of component
- poor wettability of through-hole
- unsuitable soldering parameter
- pollution of materials to be joined
Source:visual, optical inspection - general view
Description:
Problem similar to the one in the preceding example. No rework necessary.
Causes/Remedy:
- poor wettability of component
- poor wettability of through-hole
- unsuitable soldering parameter
- pollution of materials to be joined
Source:visual, optical inspection - general view
Description:
Example of ideal wetting of the upper and lower contact areas (long solder outrun, small wetting angle)
Causes/Remedy:
- / -
Source:Microsection
Description:
The vertical solder fillet is distinctly below 75%. Therefore rework is necessary.
Causes/Remedy:
- poor wettability of component
- poor wettability of through-hole
- unsuitable soldering parameter
- pollution of materials to be joined
Source:Microsection
Description:
Hole in the solder joint. The periphery of the through-hole was not completely wetted. In accordance with IEC 61191-3 this solder joint is still acceptable. Rework is nevertheless recommended.
Causes/Remedy:
- poor wettability of component
- poor wettability of through-hole
- unsuitable soldering parameter
- pollution of materials to be joined
Source:visual, optical inspection - general view
Description:
Unacceptable solder joint. The peripheral wetting is less than 75 % of the wettable area. Rework necessary.
Causes/Remedy:
- poor wettability of component
- poor wettability of through-hole
- unsuitable soldering parameter
- pollution of materials to be joined
Source:visual, optical inspection - general view
Description:
Unacceptable solder joint, since the solder fillet fills less than 75 %. Moreover there are cracks in the solder along the lead. Rework necesssary.
Causes/Remedy:
- poor wettability of component
- poor wettability of through-hole
- unsuitable soldering parameter
- pollution of materials to be joined
Source:Microsection
Description:
Unacceptable solder joints, because wetting covers less than 270° of the periphery on the soldered side. Rework necessary.
Causes/Remedy:
- poor wettability of component
- poor wettability of through-hole
- unsuitable soldering parameter
- pollution of materials to be joined
Source:visual, optical inspection - general view
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