Wave Soldering Defects
Flux Residues on a Printed Circuit Board
Flux residues visible on the board are more common due to the reduction in the use of cleaning in the industry. Over 75% of companies in Europe use no clean low residue materials. With the reliability of no clean being demonstrated in automotive products, the number of cleaning processes will continue to decline.
In Figure 1, the residues are either a result of the formulation of the flux or due to poor process conditions. Many no clean materials rely on the correct pre-heat temperature helping to minimize the residues left on the board. Wave contact time may also affect the residues left on the board. Discussion with the flux supplier should provide the correct process parameters.
Figure 1: The flux residues here could have been caused by the formulation of the flux or by poor process conditions.