Summary
Circuits for the electrical industry are preferably manufactured using screen printing techniques, which still require the use of large quantities of organic solvent blends in all phases of cleaning. In contrast to other screen printing applications, water-based pastes and dyes cannot be used here, since the screens need to be structured with direct coatings, which do not meet the required high quality standards for the print master with regard to line weight, layer thickness and edge sharpness.
The aim of the multi-stage association project was to develop a concept for the use of water in all areas of the printed circuit manufacturing process. As part of this sub-project, printing screens for water-soluble pastes were to be manufactured and tested under real-life conditions.
Results:
- Sufficiently waterproof screens of optimal quality were successfully manufactured. They are suitable for the most sophisticated technical screen printing applications. Stainless steel wire cloth with a mesh size of 325 to 400 mesh, wire diameter of 0.018 to 0.030 mm and a weave angle of 22.5° or 45° was used. The screen was then structured using direct / indirect coating technology, with a film thickness of 20 µm.
- The screens showed good printing performance when used with the silver-palladium based conductor paste (FK 1205 W) developed by the project partner.
