Steve Hello everyone. I’m Steve, a Soldering Engineer at Japan Unix.
This time, I’ll talk about a frequently asked topic: the causes of solder balls.

Solder balls refer to the phenomenon where solder forms into ball-like lumps

and scatters onto the PCB.

There are three main causes of solder balls.

Let’s take a look at each one.

Steve The first cause is “the impact when the tip contacts.”

Solder balls attached to the soldering tip may drop off due to the shock of contact.

Also, when pulling away, the heated solder

may pop and fall off.

To counter this, first, it is important to keep the soldering tip clean.

Additionally, you can prevent it by reducing the speed of contact,

or verifying the contact angle.

Steve The second cause is “the speed of solder feeding.”

If the solder feeding is too fast, the flux inside the solder

can gasify and pop, causing solder balls.

Conversely, if the solder feeding is too slow,

overheating can cause the flux inside the molten solder to gasify, also leading to solder balls.

To prevent this, it is important to properly set

the optimal solder feeding speed.

Also, making a slit in the solder itself is another effective method.

Steve The third cause is “moisture in the PCBs.”

When moisture in the PCB is heated,

it can pop and be released outward, resulting in solder balls.

To prevent this,

it is important to thoroughly manage the condition of the PCBs and components.

Especially during the rainy season,

please make sure to remove moisture before starting work.

Steve That was the explanation of the three causes of solder balls.

If you have any other questions or things you want to know,

please feel free to contact Japan Unix.

See you again next time!