Soldering Using Two-Step Fluxing
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
In soldering electronic components such as printed circuit boards, the process usually proceeds in the steps of fluxing, preheating and soldering. In the present method, the soldering process is modified to perform the pretreatment of fluxing and preheating twice so that it proceeds in the steps of first fluxing, first preheating, second fluxing, second preheating and soldering. Different fluxes are preferably used in the respective fluxing steps. In the first step, a weakly activated rosin flux including chlorine at an amount of less than 0.5 percent by weight is applied, and in the second step, a strongly activated rosin flux including chlorine at an amount of 0.5-3 percent by weight is applied. This method is easy to control the fluxing and effective to improve solderability.