● Pad surface area
● The lead diameter
● The component
When soldering a thru-hole component, the solder joint usually plays a vital part as it’s used to connect the component and the board. Thus the quality of the solder joint is closely relevant to the quality of connection. Actually, there exist many difficulties in the soldering processes such as cold solder joints or solder joints with contamination. In addition to these situations, are there any other influence factors of quality solder joint?
Surface area for pad
As the heat should be equably dissipated between the pads, the lead and the thru-hole, so enough surface area is quite essential to a quality solder joint. Inadequate pad surface will lead to the pad delaminating which means the pad separates itself from the board. This is extremely bad for the connectivity of the pad and hole wall plating.
The lead diameter
Besides surface area of the pad, the lead diameter is the second factor influencing the quality solder joint. Is the lead solid or hollow? This should be confirmed in advance. Generally speaking, a solid lead will absorb more heat and take longer time to be heated. Hence, the pad surface area should be adjusted accordingly.
An examination should be taken for component in order to ensure the heat dissipation and absorption. If the component’s lead appears to extend into the component, then the additional heat may be required to make the solder adheres to the lead, and the surface area should be adjusted accordingly.