第三讲　整机装焊　　焊接与生产时 ,焊料中会带入一些杂质 ,需要注意和控制这些杂质带来的有害作用 ,表 1列出了焊料中的主要杂质的来源、允许的极限值及对焊接的影响。表 1　焊料中的主要杂质及对焊接的影响元素 允许极限值 (Ｗ % ) 杂质来源影响焊接效果Ｚｎ 0 .0 0 2 被焊 Lecture 3 welding and welding machine production, the solder will bring some impurities, the need to pay attention to and control the harmful effects of these impurities, Table 1 lists the source of the solder in the major impurities, the allowable limits and Impact on welding. Table 1 Solder in the main impurities and the impact of welding Elements allowable limits (W%) Impurity sources affect the welding effect Zn 0 .0 0 2 was welded