Flux is a core part of all solders (both paste and wire). Flux allows component leads to flow and moisten properly onto PCB pads. Flux particles can sometimes lead to contamination or even electromigration between component leads (leading to shorts) on the PCB. High reliability systems - military, space and other fundamental implementations - typically necessitate the cleaning of notable no-clean fluxes. PCB cleaning is highly needed for these types of PCBs. The sales staff at Restronics Northwest have years of experience in various forms of flux cleaning... from high-volume batch cleaning machines to benchtop flux cleaning sprays and chemistry to remove flux residues. By analyzing the current process and supplying proper recommendations for improvement, we can reduce the manual labor necessary for hand spray cleaning and ultimately boost dependability and cleanliness by employing a DI water-based batch cleaner with aqueous chemistry.
The majority of US manufacturers make high reliability PCBs, so flux cleaning is essential. Cleaning PCBs with solvents, although extremely effective, can be very dangerous for the planet and for users. Organizations are shifting away from solvent-based cleaning and toward aqueous-based flux cleaning due to rising limits on the solvents used in vapor degreasers. Aqueous-based cleaners are usually zero-discharge, which implies that no residue or wash solution is discharged; it remains in the device. Wash chemistry is often a blend of DI water and cleaning chemicals.
The suitable cleaning chemistry must fit the composition of the soils as part of PCB cleaning (could include flux residue, oils, or other contaminants). Most people try to apply a basic alcohol cleaner but it generally causes a white sediment and does not eliminate flux. This is particularly problematic when clients need the PCB to be conformally coated. Most conformal coatings won’t adhere appropriately unless the circuit board has been cleaned effectively. Before applying conformal coatings to military and space applications, all flux residues should be removed and verified using an Ionic Contamination tester.