Characterization of a solder paste printing process and its optimization

The objectives of this research are to model the screening process with planned experiments and to identify the optimal setting of the process parameters so as to minimize the printing defects. The percentage volume matching (PVM) and defects per unit (DPU) are the two quality characteristics of interest. A fractional factorial design was employed to study simultaneously the effects of eight process factors on the PVM and DPU and their possible interactions. Subsequent analysis shows that a low level of the stencil cleaning interval and low temperature results in the minimum DPU while maintaining a PVM very close to 100 per cent. Empirical relationships between these two quality characteristics and the important factors were formulated using regression analysis and close matches were found during subsequent validation experiments.