Parameter interactions in stencil printing of solder paste

The stencil printing of solder paste is affected by a large number of factors, including printer settings, stencil aperture geometry, and environmental conditions. A fractional factorial experiment was designed to determine the effects and interactions of some of these parameters. A two-level design on eleven factors was used, with all main effects, two-way interactions and most three-way interactions estimable. The height of the solder paste deposit was measured at certain points on each of sixty-four boards. These measurements were analyzed using ANOVA and ANCOVA, and the most significant factors and interactions identified.