Ultimate quality thanks to early defect detection

Checking all the relevant points in the production process is essential, especially in terms of analyzing the causes of defects, fixing them, and – most importantly – preventing them in the future. That’s why solder paste printing is of fundamental importance for manufacturing complex assemblies: If paste printing isn’t performed correctly, the defect can impact the subsequent assembly and the soldering process, resulting in a tilted component or a poor or missing solder joint.

Optical inspection systems designed for solder paste inspection (SPI) quickly and reliably check the solder paste deposits on the circuit board. They measure the following defect features: surface, height profile, and volume. The measurement and image data from the SPI can be fed back to the solder paste printer (closed loop) and simultaneously transferred onto the automatic placement machine (closed forward loop) so it can adjust the placement position to the actual solder paste printing. Situations in which components are still assembled on the target position despite offset solder paste are critical because this results in a risk of a lifted lead without electrical contact or tombstoning. Solder paste defects such as offset paste, insufficient paste, or bridging are some of the typical defects that the SPI detects. This makes it possible to draw conclusions on improving cleaning cycles, correcting offsets, or even eliminating weak points in the PCB design.