Experimental study of stencil/substrate separation speed in on-contact solder paste printing for reflow soldering

The paper reports on an experimental study on solder paste printing in which the speed of separation between stencil and substrate was varied and the resulting prints were examined for height and defects. The main conclusion of the study is that the speed of separation does not significantly affect the number of printing defects for some solder pastes whereas for others a very low value of separation speed results in more defects. These differing responses reflect the differing solder particle size distributions and chemical structures of the four solder pastes tested. The flow behaviour of the pastes is a crucial factor in determining defect rates.