Prevent misprints in the production of electronic assemblies with thorough cleaning of stencils and screens.
Johann Wolfgang von Goethe once said, “Whoever misses the first buttonhole will never get the coat properly fastened.” This also applies to the cleaning of electronic assemblies. Inadequate cleaning can lead to malfunctions and quality issues. Thorough cleaning of stencils and screens is therefore essential for the production of electronic assemblies with optimal printing results. A clean stencil and a cleaned screen are key factors for success and should therefore always be thoroughly cleaned.
STENCIL CLEANING
Precision Begins in the Details
A clean stencil or a cleaned screen is an important prerequisite for optimal printing results. Solder pastes, SMT adhesives, or thick film pastes are printed or applied through stencils or screens. Residues on the stencil surface can harden and cause printing errors, which is why thorough cleaning is essential at this early stage of production.
Various methods are available for cleaning stencils and screens, which can be tailored to individual requirements.
MACHINE CLEANING
For High Throughput
Reliable production of electronic assemblies requires precise work at every step of the production process. Especially in stencil cleaning, a machine cleaning method is often the best choice as it delivers reproducible cleaning results and significantly reduces mechanical damage. This way, optimal printing results and higher quality of the produced assemblies can be achieved.
MANUAL CLEANING
For Low Throughput
When the throughput is low, manual stencil cleaning can be a reasonable alternative to machine cleaning. However, some important steps should be taken to avoid damaging the stencil.
This includes, for example, the use of a lint-free stencil cloth and a gentle approach without too much force. If these points are considered, manual stencil cleaning can also lead to good cleaning results.
SOLUTION FOR MISPRINTS
Misprint and Underside Cleaning
Even with the greatest care and thorough cleaning in the production of electronic assemblies, misprints on the board can occasionally occur. However, there is no need to worry – in such cases, misprint cleaning can provide a solution.
Cleaning of Misprints
Misprint cleaning enables the targeted removal of erroneously applied solder paste, resulting in higher quality of the produced assemblies and reduction in scrap. Particularly in the case of high-quality, double-sided assemblies that have already been soldered on one side, cleaning is recommended, as misprinted assemblies can be salvaged after cleaning instead of being discarded as scrap. With this process, misprints can be effectively eliminated
Underside Cleaning – SMT Printing
To achieve optimal and consistent printing results in SMT printing, it is important to regularly clean the underside of the stencils.
An important factor in this regard is the choice of cleaner, which should not only have good cleaning power and low media consumption, but also high compatibility with the solder paste used. Regular cleaning of the underside of the stencil can maintain a consistently high printing quality standard.
