In the manual welding iron cored solder wire, soldering iron head temperature set at 300 DEG C. The green electronic technology requirements brought a huge challenge to the flux cored:
1) the active temperature of rosin general below 300 DEG C temperature exceeds 315 DEG C when almost no activity, rosin cored lead free soldering flux for soldering activity which is widely used at present.
2) welding harmful residues of more, the rosin based flux contains halogen and its residues in the halogen ions in high humidity environment with high temperature easy corrosion circuit board, solder joints and components, resulting in insulation of difference and the circuit connection is bad and waste liquid produced in the residues of the cleaning process also seriously pollute the environment;
3) rosin based solid flux for soldering solder easy to change color, high temperature rosin easy carbonized color, black spot, affect the appearance, limiting the its use in high-end electronic products.
Flux vector components deal with organic acid active ingredients and other components with good solubility, can form a uniform liquid. The second is to satisfy the actual wire cored solder preparation and welding temperature requirements. Sn-0.7Cu lead free cored solder wire extrusion molding temperature of 110 DEG C to 130 DEG C, the flux required at 110 DEG C to melt completely, formation of a uniform liquid and flow of good, can successfully pressed into the solder wire is formed inside the continuous cored. In addition to the flux cored wire is not out in the drawing process, the flux required at 80 DEG C for solid. Lead-free solder iron hand soldering temperature above 300 DEG C, the boiling point of flux should be and close to, not deviate too much. This is because of the low boiling point of flux vector is easy to volatilize, in the welding process in the premature loss of activity and high boiling point will lead to residue after welding is increased. Rosin is typical of a carrier material, temperature was neutral, the metal no any corrosion and dissolved organic matter, does not absorb moisture, non conducting, is good active agent and film-forming agent, has been used as the carrier, carrier group for stearic acid boiling point for 37.61 degrees, adding rosin can adjusting the boiling point. But Sn-0.7Cu lead-free drug core solder wire manual soldering iron temperature is high, lose activity rosin, carbonized color and experimental study show that reduce rosin adding amount and adding other organic matter can achieve good welding.