What is the main characteristic of a solder joint that passes inspection?

A solder joint that passes inspection is characterized by a smooth and shiny appearance. This is important because a smooth and shiny surface typically indicates that the solder has properly melted and flowed, creating a robust connection between the components and the substrate. Such an appearance suggests good wetting of the surfaces involved, which is essential for achieving strong mechanical and electrical joint integrity.

Additionally, a smooth and shiny solder joint is also less likely to have defects such as voids, cracks, or cold solder joints, which can compromise the reliability of the electronic assembly. A properly formed solder joint will not only meet aesthetic standards but also functional requirements, ensuring a secure electrical connection.

This characteristic is a key indicator in the IPC-A-610 standard, which lays out quality criteria for electronic assemblies, emphasizing the significance of visual inspection as a preliminary assessment of solder joint quality.