A Solder Paste Screen Printer for SMT is needed to screen solder paste onto the printed circuit board (PCB) before placement of surface mount components.
Solder Paste Screen Printer for SMT have been widely used in electronics by the PCB industry for screen solder mask. This equipment / machine has also been extensively used in the hybrid industry for screening solder paste. However, different equipment is used for the screening of solder mask and solder paste. The cost of screen printers can vary widely, depending on their degree of automation and the size of boards they can handle.
Solder Paste Printing Systems are available in three configurations: manual, semi-automatic and fully automatic. The machine can be table mounted, stand-alone, or in-line. Many semi-automatic printers offer manual vision alignment capability, while fully automatic printers offer automatic vision alignment.
Stencils are preferred over screens because of better image accuracy, volumecontrol, and longer service life. Screens are not in common use today. Stainless steel is the most common stencil material. Other choices include brass 42 and molybdenum. Chemical etching is commonly used to fabricate stencils.
Several other methods have been developed to aid fine pitch applications including plating (electroless nickel), electrodeposition, laser cutting, and electropolishing. Stepped thickness stencils have been developed to apply various thickness of solder paste to different component types on a substrate. Fine pitch printing require very accurate alignment of the stencil apertures to the land patterns.