Investigating Intermittent Soldering Defects

This technical report investigates intermittent soldering defects encountered in the PCB assembly process. It outlines the common misconception that soldering materials are solely responsible for these defects, emphasizing the need for a comprehensive examination of various factors including equipment setup, environmental conditions, and handling processes. The report presents a case study detailing a specific incident of intermittent solderability issues, highlighting the challenges faced during diagnosis, particularly the difficulty in replicating the problem during vendor visits. A checklist for investigating solderability issues is provided, covering aspects such as screen printer setup, pick-and-place processes, and reflow oven performance. The report further discusses the importance of examining component characteristics and environmental factors, as well as the optimization of reflow profiles. It concludes by stressing the significance of vendor collaboration and the need for commitment and patience in resolving soldering issues, suggesting that effective communication with vendors can lead to successful problem-solving.