Mpm Printer Squeegee blades are an intracule part of the print process. In a typical printing process, the paste does not fill the aperture until the paste bead has traveled at least 75% beyond the leading edge of the aperture. The aperture fills from the trailing edge of the aperture backwards. It is the rolling of the solder paste bead that generates the downward force that drives the paste to fill the aperture. This understanding of the aperture filling process is important to understanding why the attack angle of the blade becomes critical.