High-Energy Particles Online Discriminators Based on Nonlinear Independent Components

The present invention relates to a method for depositing a viscous material (11), such as solder paste, onto a substrate (16), such as a printed circuit board. The solder paste is expelled (12) out from a dispenser (20) into a void between a pair of flexible members (30) extending therefrom for contact with a foraminous member (12) such as a stencil, proximate the printed circuit board. A relative motion is imparted between the dispenser and the foraminous member so that at least one of the flexible members forces the solder paste through the openings in the stencil and onto the circuit board. In accordance with the invention, the dispenser is pivoted when the relative motion is imparted between the dispenser and the stencil to raise the leading one of the flexible members a predetermined distance from the stencil. In this way, the solder paste expelled from the dispenser will remain substantially confined between the flexible members, yet be allowed to mix with whatever portion of the solder paste (typically flux) remains on the stencil after the previous pass of the dispenser thereacross.