White residue, a sticky film and loose solder balls are three different post-soldering conditions. They should not be treated as one general \u201cdirty PCB\u201d problem.<\/p>\n\n\n\n
White residue may originate from flux, the cleaning process or the solder mask. A sticky film usually points towards remaining organic material or an incomplete cleaning process. Loose solder balls are metallic particles produced by soldering, printing, handling or material conditions.<\/p>\n\n\n\n
None of these observations identifies the root cause by itself. The first question is not simply how to remove the contamination, but when it appeared, where it is located and which process created it<\/strong>.<\/p>\n\n\n\nObservation<\/th> What it may indicate<\/th> What appearance alone cannot confirm<\/th><\/tr> White powder, haze or spots<\/td> Flux residue, incomplete rinsing, cleaner incompatibility, poor solder-mask cure or a material change<\/td> Ionic contamination or corrosion risk<\/td><\/tr> Sticky or tacky film<\/td> Remaining rosin or resin, incompletely conditioned flux, excessive flux, cleaning-agent mismatch or partial cleaning<\/td> Whether the residue is electrically harmful<\/td><\/tr> Loose solder balls<\/td> Printing, placement, reflow, wave or selective-soldering instability<\/td> Which process parameter created the balls<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n Table of Contents<\/h2>