Red ink test

Red ink test
Red Ink Test - A technique for verifying the surface mount technology (SMT) of electronic parts with or without empty soldering or cracking. This is a groundbreaking experiment that is commonly used in surface mount technology (SMT) on PCB assembly to help engineers check for flaws in the soldering of electronic components. Because it is a destructive experiment, it is generally only used on boards that have been unable to detect problems through other non-destructive methods, and almost exclusively used in analysis.
BGA (Ball Grid Array) packaged IC, usually in order to better understand the product's undesirable phenomenon, as a reference for quality improvement of subsequent production, or to clarify responsibility.
The method is to use the appropriate viscosity of red syrup (red ink) to inject under the BGA IC suspected of having poor soldering habits. First, confirm that the red syrup has completely entered the BGA IC, wait for a while or bake the red syrup to dry. Later, using a tool (usually a flat-blade screwdriver) to pick up directly from the board (PCB), it is also useful to glue the BGA IC and then use the drawing machine to hard remove the IC. It should be noted that the heating temperature must not exceed the temperature at which the solder remelts.
The principle is to use the liquid to have the characteristics of penetration, which can penetrate all the gaps to judge whether the welding is intact. In general BGA ICs, the two ends of the solder balls should be individually connected to the circuit board and the BGA IC body. If a red syrup appears in the spherical place that should be welded, it means that there is a gap in this place, that is, there is a weld break. The rough surface of the welded fracture is judged to be the original poor welding or the fracture caused by improper use.
Service flow