Misprint Cleaning

As the value of double-sided PCB assemblies continue to rise, it becomes increasingly important for manufacturers to be able to recoup their cost from the assembly when a misprint occurs on the B-side (A-side was successfully printed and components placed and soldered, and when a misprint occurs during the printing process on the B-side).

Typically, the cleaning of misprints occurs by hand wiping the misprinted side or cleaning in a conventional stencil type cleaner. Concerns with this approach include:

  • Wiping the misprinted side can wedge or trap solder paste in the solder mask, through-hole vias, and/or into other geometries;
  • Numerous quality problems can occur due to lack of control and definition;
  • Traditional stencil cleaning machines are designed to remove wet solder paste from stencils. Most stencil cleaning processes do not rinse the stencil with water, or may utilize reused water that can include trace levels of metals;
  • Cleaning a production board in a machine designed to clean stencils may result in failure to meet ionic cleanliness standards;
  • The stencil cleaning agent is typically not adequate for cleaning reflowed flux residues from the A-side of the assembly.

Electrovert Aquastorm™ series cleaners (in-line and batch) offer a misprint cleaning feature. This consists of a multi-stage filtration system designed to filter to 5 microns (suitable for a Type 5 solder paste). This feature captures and prevents solder spheres from being re-deposited onto the product. Thus, it provides the ability to deflux side A and clean the misprinted side-B at the same time without solder sphere contamination.

Aquastorm series cleaners with the misprint feature are used in multiple cleaning applications:

  • PCB assembly
  • Defluxing
  • Portable device cleaning
  • High reliability electronics manufacturing
  • Microelectronics
  • Semiconductor
  • Specialty applications