| 摘要 |
<p>PURPOSE:To improve the wettability of soldering in the course of reflow soldering so that no inferior soldered part can be produced and necessity of manual modifying works can be eliminated by making the extent to which paste-like cream solder to be applied to a printed wiring board is applied larger than the pad to which surface mounting parts are fitted. CONSTITUTION:In the course of fitting surface mounting parts 6 to a printed wiring board 5 by reflow soldering, the extent 9 to which paste-like solder to be applied to the board 5 is applied is set larger than the pad 1 to which the surface mounting parts 6 are fitted. For example, the part of the cream solder which spreads to the outside of the chip parts fitting pad at the cream soldering time flows to the electrode of chip parts by the surface tension of the molten solder and the surface tension of the contained flux at the reflow soldering time. Therefore, the oversize of the cream solder to the fitting pad 1 is freely set in accordance with the size of the chip parts 6 to be mounted, that is, the size of the electrode 7 by utilizing the action, so that the cream solder can be applied in an appropriate applying size 9.</p> |
