Contents
What causes grainy solder joints?
Dull (non-shiny) solder joints are usually the effect of coarse grain structure in the solid solder joint (though there can be other causes). The more slowly a joint cools, the coarser the grain growth and, conversely, the faster the joint cools, the finer the grain growth and the shinier the joint.
What is the appearance of a cold solder joint?
A cold solder joint occurs when the solder does not melt completely. A result of insufficient heat, cold joints are often characterized by being rigid, rough, and uneven in appearance. This solder mistake creates an unreliable joint that is highly susceptible to cracking and failure.
Should a solder joint be shiny?
A good solder joint should be shiny and fill but not overflow the pad. Nearly all bad solder joints are caused by one of three things: not allowing the wire and pad to heat sufficiently, applying too much solder, or melting the solder with the soldering iron instead of with the wire lead.
What causes a cold solder joint?
The causes for cold joints are manifold. Amongst the most common causes for this defect are disturbances such as vibrations during the cool down period of the solder, or a too high process temperature which has caused the flux to break down prematurely.
Are cold solder joints bad?
A ‘Cold Joint’ is one where the solder did not melt completely. It is often characterized by a rough or lumpy surface. Cold joints are unreliable. The solder bond will be poor and the cracks may develop in the joint over time.
How can you tell if you have a good solder joint?
A good solder joint should have an even band of solder showing all the way around. If you see an area that looks as if it needs more solder, brush a little flux onto the joint. If the joint is still warm, the flux will melt and flow into the void. Then reheat the joint and resolder.
What happens to the grain in a solder joint?
The more slowly a joint cools, the coarser the grain growth and, conversely, the faster the joint cools, the finer the grain growth and the shinier the joint. Dull or grainy joints are not a big concern – the grain structure will grow in a joint over time anyway.
What does a cold solder joint look like?
Cold solder joints often appear dull and make convex mounting on the pins and the board flex areas. Sometimes, they also take rough shapes, as shown in image 2.
Why are the solder joints on my car so dull?
Dull (non-shiny) solder joints are usually the effect of coarse grain structure in the solid solder joint (though there can be other causes). The more slowly a joint cools, the coarser the grain growth and, conversely, the faster the joint cools, the finer the grain growth and the shinier the joint.
Why is my solder gun cold at the tip?
For engineers using soldering stations, the only possible reason you could encounter cold solder joint problems is dirt that collects on the solder gun’s tip. This problem could also lead to overheating of solder joints. Therefore, the first step to solving cold solder joints is to appropriately clean the tip of the soldering iron.