Abstract
<title>Abstract</title> <p> This study optimizes the printing process parameters for high density Surface Mount Technology (SMT) micro-assembly of solder pastes using the Taguchi robust design approach. The rise of electronic packages and fine pitch components have made solder paste printing the most important and vulnerable process in SMT. The effects of three process parameters - squeegee speed (30–70 mm/s), print pressure (4–10 N) and snap-off distance (0.05–0.25 mm) - were studied in an L9 orthogonal array design. Defect rate (%), calculated based on six categories of PCB defects from the <italic>norbertelter/pcb-defect-dataset</italic> (Kaggle), was chosen as the quality characteristic, with 600 labeled PCB defect images including missing holes, mouse bites, open circuits, short circuits, spurs and spurious copper. Signal-to-Noise (S/N) ratio (smaller-is-better), Analysis of Variance (ANOVA), and regression analysis were conducted to determine optimal levels and contributions of each factor. The findings show squeegee speed has the largest contribution to variance (42.3%), followed by print pressure (31.7%) and snap-off distance (18.4%). The predicted optimal setting has achieved an average 62.3% reduction in the total defect rate across all types of defects. A residual regression of R² of 0.9612 was obtained when the predicted optimum was tested. The current approach offers a systematic approach to enhancing first pass yield in high density SMT manufacturing. </p>