Solder Paste Printing
To apply solder paste to a printed circuit board, stencil printer, and to a lesser extent screen printers, are used. Following the printing, components are placed on to the solder paste deposit. The volume of paste printed is selected via the stencil thickness. In the printing process, the stencil is placed exactly on to the pcb and aligned. A squeegee moves the paste across the stencil, filling the openings (aperture). Once the squeegee has reached its end position, the stencil is lifted off from the pcb, the solder deposits separate from the stencil and remain on the pads of the pcb.