Although water soluble (OA) flux is technically the easiest flux to remove, it is also the most damaging type of flux if not removed. A dishwasher lacks the pressure and nozzle design to produce the very small water particle size required for thorough under component penetration (impingement).
Dishwasher �technology� is based on high flow, low pressure. Although flow is one component of thorough cleaning, high-density, low standoff applications such as BGA�s mandate significantly higher pressures than any dishwasher or laboratory cleaner can provide. Anecdotally, my wife reminds me to always rinse off the dishes before loading the dishwasher, otherwise, the dishes may not come clean. The surface of my dishes is free from reflowed components mounted 2 mils off of the surface. The temperature in a reflow oven generally exceeds those of a kitchen oven. Additionally, if using a chemical additive in a dishwasher, be prepared to replace quite a few parts as many chemicals used in de-fluxing deteriorate the seals and other parts of a dishwasher. Also, most chemical additives have a chemical de-foaming package built into them. The de-foaming package is temperature activated. Most dishwashers can not sustain the heat required to keep the de-foamers working. The result may be reminiscent of �the blob�.
If cleaning is in your future, consider a cleaning system designed for circuit assemblies, not plates and spoons.
Mike Konrad Aqueous Technologies 909.944.7771 ext 29 www.aqueoustech.com
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