Solder Paste Viscosity and Area Ratio Print Performance
Matching paste particle size and viscosity to stencil area ratio maintains stable transfer efficiency above 80 percent on fine-pitch components.
Micro-Stencil Rework
Localized Deposition
Manual application of solder paste to a single component site using a miniature stainless steel foil allows for the replacement of complex parts without affecting the rest of the board. This localized printing method provides a repeatable volume of material for micro-stencil rework when dealing with fine-pitch devices like ball grid arrays or land grid arrays.
Repair Precision
Execution of the process begins with the complete removal of old solder and residue from the pads using a desoldering station. Once the site is clean, the technician aligns the micro-stencil rework tool over the pads using high-magnification optics. Solder paste is then spread across the small foil with a hand-held blade.
Removing the foil carefully prevents the freshly printed deposits from smearing before the new component is placed.
Thermal Management
Selective reflow heating follows the deposition to complete the joint formation. A localized hot air stream or infrared heater targets the reworked component while shielding nearby parts from excessive heat. Excessive temperature at this stage can cause delamination or damage to adjacent sensitive components.
Successful completion of the repair requires a final x-ray inspection to verify that the internal balls have collapsed and wetted correctly to the pads.