| 摘要 |
PURPOSE:To accurately judge whether a soldered part is good or not by a method wherein a transmission-amount distribution curve for X-rays projected on a board on which a component has been mounted by a soldering operation is compared with a straight line connecting two points corresponding to contacts. CONSTITUTION:When a component 3 is soldered to a board 2, a soldered part 1a is a good product and a soldered part 1b is a defective product. The board 2 including the soldered parts 1a, 1b is irradiated perpendicularly with X-rays. When their transmission amount is measured, a transmission-amount distribution curve L' for the good product is downward convex, and a transmission-amount distribution curve L' for the defective product is concave. Consequently, the curve L' is situated under a contact-passage straight line L1 in the case of the good product and the curve L' is situated on the straight line L1 in the case of the defective product with reference to the straight line L1 which connects points P1', P2' on the transmission-amount distribution curve L' corresponding respectively to the contact of a surface curve for the soldered part with the board 2 and to the contact of the curve with the vertical side face of the component 3. |
