The stencil maintenance and poorly screen-printed boards has become increasingly important in the production of surface-mounted electronic boards.

Increasing integration, density and new components place new demands on stencil cleaning.

Correct solder paste volume is a critical issue for fine, ultra-fine, chip-scale, BGA and flip-chip components.

Insufficient solder paste deposition due to partial occlusion of stencil openings is one of the main causes of defects.

Correct and regular cleaning of stencils ensures a constant and even deposit.

Stencil maintenance should remove all metal dust particles and flux (organic substances) from the stencil openings without damaging the stencil.

The Institute for Printed Circuits estimates that around 70 per cent of defects in the surface-mounting process are due to screen-printing problems.

Today, there are water-based products (PROMOCLEAN™ DISPER 610), semi-water-based products (TOPKLEAN™ EL 606) and solvents (PROMOSOLV™ 70) that are effective, safe for workers and safe for the environment.

Until a few years ago, cleaning was done manually with isopropyl alcohol (IPA).

Today, there are immersion systems with ultrasound or air sprays that guarantee high and repetitive cleaning results.

In addition to cleaning stencils, it is also possible to clean misprinting boards and squeegee.