You are correct, white residues on the pallets and the boards are unattractive and unprofessional, so everybody always has to work to minimize or even eliminate these results. While there are many sources of white residues, the most common source of white residues are the halites in the no-clean fluxes which have not been encapsulated by the heat of the wave solder system. As such, those salts are open to the atmosphere and can cause corrosion and premature failures.
To clean the pallets, I would recommend a strong, noncorrosive, aqueous based cleaner (you don’t want to use flammables around a wave solder machine, and the fast-drying solvents would evaporate too quickly around the heat of the systems). While there are several good ones on the market, MicroCare makes an excellent product which is safe for people and the pallets.
The “Reflow Oven Cleaner” is nonflammable, slower-drying, and actually uses the heat of the pallet and the wave soldering system to improve it’s cleaning. MCC-ROC is available in refillable pump sprays, gallons, pails and drums.
To clean the boards, now this is a trickier issue because we can’t leave any residues, you require faster drying so your people aren’t wasting too much time on this process, and you can’t use a really strong cleaner (like the Reflow Oven Cleaner) because you’ll worry about materials compatibility.
One excellent option is PowerClean™ from MicroCare. PowerClean is just about as strong a cleaner as you can get in a nonflammable, residue-free defluxer. Importantly, it was engineered specifically to remove the white residues frequently produced by lead-free materials. Not only will it remove those residues, it actually precludes their formation. So most customers will find PowerClean a great choice on lead-free PCBs. MCC-PW2 is available from all authorized MicroCare distributors around the world.
