| 摘要 |
PURPOSE:To lessen delay of delivery and reduce increase of failure expenses due to reproduction by finding an arrangement error of a multilayer printed wiring board on each internal layer layer face at an early stage. CONSTITUTION:On a printed wiring board 1 provided with clearance holes at corresponding positions previously on each of internal layer layer fades, hole drilling is carried out while continuously measuring torque and z-axial moving amount of a spindle motor 8. It is possible to find an arrangement error of an internal layer at an early stage by continuously measuring variation of torque of the spindle motor 8, and accordingly, it is possible to lessen delay of delivery and reduce increase of failure expenses due to reproduction. |
