Automated stencil cleaning is the preferred method to ensure that the cleaning results are always reproducible as compared with a manual cleaning process. Manual cleaning can cause mechanical damage and soften the stencil epoxy over time resulting in possible delamination issues.
IPC standard (IPC 7526), recommends the use of an automated cleaning system in order to meet all production requirements.
There are numerous processes available for stencil cleaning including spray and ultrasonic dip tank processes. Depending on the type, these can be used with solvent and aqueous-based cleaners. These cleaning machines can be further differentiated by the number of chambers that are available for the various process steps such as cleaning, rinsing and drying. This enables the cleaning process to take place in one or more chambers. Steel stencils, fine pitch and nano-coated stencils as well as screens are commonly cleaned in these machines.
When cleaning pump print stencils, one should pay particular attention to the correlation between the aperture thickness and size. Compared to typical SMT stencils, pump print stencils require longer cleaning cycles.
Cleaning agent options for automated stencil cleaning applications are detailed below. All ZESTRON cleaning agents are in compliance with the latest RoHS, REACH, and WEEE regulations worldwide in addition to current worker safety standards and applicable environmental requirements.