Finishing and refinement of smt stencils

Optimisation of stencil printing through surface treatment

Despite the use of high-quality materials in combination with state-of-the-art laser systems, fine burrs form during the laser cutting process and plasma residues can remain on the smt stencils. Depending on the stencil and pitch, the smt stencils are optimised for individual requirements after production by the manufacturer BECKTRONIC GmbH using different post-treatment processes. The efficient final treatment of the smt stencils not only saves time in the stencil printing process, but also cost in particular.

Surface treatments of smt stencils in comparison

The double-sided brushing process offers the possibility of efficiently removing residues. A process that smoothes the underside of the smt stencil and slightly roughens the squeegee side. This primarily serves to ensure error-free solder paste printing. BECchem - a unique chemical treatment of the stencil surface - guarantees the highest stencil quality, especially for small structures. This electro-chemical treatment reduces the roughness of the pad's inner edges to less than 1 micron Rz. The positive effect of this process is obvious: through the sustained optimisation of the solder paste release behaviour, precise printing is achieved and paste residues at the stencil openings are minimised. Stencil life is increased while cleaning cycles are reduced.  BECnano - a high quality nano-coating optimises the stencil surface by imparting paste repellent properties to the pcb side. These reduce the drying of solder paste residues and thus the cleaning intervals.