Electronics Forum | Thu Oct 05 16:04:00 EDT 2006 | GS
I am not expert, just my comment, the total ionic contamination allowed after SMT, by using No Clean process, theoretically it should be close to Zero. Any way the Standard IPC-JSTD-001 allows 1,56 ugr NaCl/cm2 for the final Printed Board assembled.
Industry News | 2018-09-23 09:57:15.0
Industry-leading associations IPC and SMTA jointly announce the High-Reliability Cleaning and Conformal Coating Conference, scheduled to take place November 13-15, 2018 at Chicago Marriott, Schaumburg, Illinois. The conference is focused on the cleanliness of highly dense electronic assemblies to achieve quality and reliability within the stated in-field environment.
Technical Library | 2020-03-09 10:50:17.0
A customer called the Helpline seeking advice for cleaning no-clean fluxes prior to applying a conformal coating. The customer's assemblies were manufactured with a no-clean rosin based solder paste (ROL0) and were cleaned with an isopropyl alcohol (IPA) wash. After cleaning, a white residue was sometimes found in areas with high paste concentrations and was interfering with the adhesion of the conformal coating (Figure 1). For conformal coatings to adhere properly, the printed circuit board (PCB) surface must be clean of fluxes and other residues. In addition, ionic contamination left by flux residues can lead to corrosion and dendrite growth, two common causes of electronic opens and shorts. Other residues can lead to unwanted impedance and physical interference with moving parts.
SMTnet Express, Septemeber 8, 2016, Subscribers: 26,370, Companies: 14,943, Users: 41,052 How Clean is Clean Enough – At What Level Does Each of The Individual Contaminates Cause Leakage and Corrosion Failures in SIR? Terry Munson, Paco Solis
10.06 micrograms of NaCl equivalent per square inch (1.56 micrograms NaCl equivalent per square centimeter). There is no industry standard for acceptable bulk ionic levels, but it is better to have as low a value as possible