| 摘要 |
PROBLEM TO BE SOLVED: To provide a reflow method for lead-free solder by which thermal damage to flux is remarkably reduced without impairing a soaking property on a board. SOLUTION: In the reflow method for a printed board using lead-free solder whose melting temperature is 195-220 deg.C, a first stage preheating is performed at 140-150 deg.C for 20-60 sec and a second preheating is performed at 180-200 deg.C for 40-80 sec. Since thermal damage to flux contained in a solder paste is remarkably reduced by the above temperature profile and the soaking property on the board at the reflow peak temperature is also satisfactorily obtained, stable soldering is ensured even in an atmospheric reflow. |
