The effective removal of misprinted solder paste and adhesives can oftentimes become more cost effective than their disposal. This is particularly true for double-sided, populated assemblies, which due to their added value need to re-enter the process after the cleaning step. The contamination to be removed consists of misprinted solder paste as well as flux residues from the already soldered and populated side.
After extensive studies conducted by independent research institutes, ZESTRON was able to show that no electrically conductive residues remained on the substrates. This is of particular significance, especially for high reliability applications.
The increased usage of OSP coated assemblies, has provided for a unique application. While removing any misprinted solder paste from assemblies the cleaning process has to ensure that sufficient organic solder protect remains. ZESTRON therefore collaborated with renowned material manufacturers to ensure the full compatibility of our products. It was found, that it is of particular importance to remove misprinted solder paste immediately after printing, simply to minimize irreparable damage caused to this protective film.
The cleaning of misprinted assemblies can be easily accomplished by common stencil cleaning equipment. ZESTRON therefore recommends the use of VIGON® SC 200, which is water based. For the removal of flux residues as well as solder paste from single sided reflowed assemblies, the use of VIGON® SC 202 is preferred due to its slightly alkaline pH value.
For solvent-based processes, ZESTRON® SD 301 has been specially developed to set new standards for misprint and stencil cleaning processes.