Flux residues removal

Spray batch and spray in-line cleaning systems for OA, no-clean, and RMA pastes and lead-free flux residues Removes all types of flux residues including lead-free in batch washing Flux residue removal in ultrasonic immersion cleaning systems requiring no sump side additives... 

The impact of Pb-free technology on wave soldering has largely occurred in the equipment performance. It has been determined that the same solder bath temperatures that are used for Sn-Pb processes (250 to 270°C) are suitable for the Sn-Ag-XCu Pb-free alloys. Therefore, excessive dross formation and flux residue removal have not become a significant problem during equipment operation. The lack of shiny fillets with the Sn-Ag-XCu alloys has been addressed by modified alloys having Ni and Ge additions that alter the solidification process, which leads to shinier fillet surfaces. 

Fig. 20 Side view of T-resonator with fiux residues visible on the left, and flux residues removed on the right. Source Ref 43...

It is sometimes necessary to remove flux residues after processing due to their corrosive nature. This can be an added source of variability. 

For optimum corrosion resistance it is recommended that similar composition fillers be used wherever possible, and obviously any flux residues that may be present must be removed. 

Trichlorotrifluoroethane (CFC 113) was widely used in the electronics industry for the removal of soldering flux residues from printed circuit boards, for degreasing components in the precision engineering industry, and for the dry cleaning of garments. 

This is a method solely used to obtain crystals of the borides. The raw materials of the borides are mixed into large amount of a low melting metal (e.g. Al, Cu, Sn) which will function in the role of the flux for the crystal growth, and then the mixture is heated. The flux is removed by an acid or alkali leaving the crystals as a solid residue. 

An interesting combination of methods is the polysulfide flux method, which can be usedforthe preparation of Ln202S (Ln trivalent rare-earth ion)-based luminescent materials (e.g. Y202S Eu or Gd202S Pr) [5.228]. In this method, the mixed oxides of the metals are mixed with excess sulfur and an alkali metal carbonate. On heating, the alkaline carbonate decomposes and reacts with sulfur to form a Uquid polysulfide flux. The oxides react with the polysulfide flux to form the oxysulfide. Flux residues can be removed by washing the reaction product in water. 

Open top and vacuum vapor N/A degreasers for circuit assembly cleaning, and flux and ionic residue removal Batch or in-Une vapor N/A... 

Precision cleaning of electronic parts in removing no-clean and rosin flux residues in vapor degreasing and cold cleaning... 

Hand wipe and immersion N/A cleaning for removal of no-clean water soluble and rosin solder paste, white residue associated with isopropanol cleaning, and flux residues... 

An active flux chemically removes the oxide film, has an acid base, and is highly corrosive. These fluxes are usually hydrochloric acid in which zinc has been dissolved to form zinc chloride, known as killed spirits . Any joint prepared using an active flux must be thoroughly washed in warm water when soldering is completed, to remove any flux residue. For this reason an active flux is not suitable for electrical applications. 

The contamination that must be removed after the soldering process is predominantly from flux residues. The removal of flux residues from the soldered assemblies (6) is generally the most critical application. Thus it is the important fliat the assemblies are cleaned. A subsequent coating process demands a very clean and residue-free surface to assure long term stability of the coating against environmental stresses such as humidity. ... 

There is a large number of products on the market that are mixtures of water and water-soluble organic solvents. These media are recommended for the removal of solder paste, SMT adhesives and flux residues from stencils, misprints and populated reflowed PCBs."... 

The substrates that have to be eleaned should be free of all kinds of residues that might have some negative influence on the functionality of the substrates. The eontamination consist predominantly of flux residues, solder paste or SMT adhesive. Another important aspect with respect to the cleaning result is the compatibility between substrates and the cleaning chemistry. It is painless to remove the contamination while destroying the substrates. 

A semi-aqueous cleaning process consists of a wash cycle using a mixture of different organic solvents followed by a rinse with deionized water. Organic contaminations, predominantly rosin flux residues, are removed through the lipophilic solvents, whereas the ionics are minimized by the polar rinse media. The different kinds of solvent formulations that are... 

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