DETECTING DEVICE FOR HOLE OF CORE MATERIAL OF MULTILAYERED PRINTED BOARD USING METALLIC PLATE AS CORE MATERIAL

摘要

PURPOSE:To detect the position of a through hole nondestructively and precisely without contacting a multilayered printed board by impressing a magnetic field crossing the surface of the printed board at right angles and measuring variation in magnetic density at the through hole part and its periphery by a magnetic head. CONSTITUTION:The magnetic field crossing the surface of the multilayered printed board is impressed by a coil, and the magnetic head 8 as a magnetic flux detecting means is arranged on the surface side of the board. Magnetic flux penetrating the board is more at the through hole pat than at its peripheral part. Then X and Y motors 16 and 17 are driven with driving signals from X and Y motor driving control parts 14 and 15 to move the head on the board in two orthogonal directions. When the heads 8 reads the through hole part in this state, the detection output increases. When the detection output exceeds a specific value, a level decision part 10 outputs a hole detection signal to a driving decision part 13 to stop the motors 16 and 17. Thus, the through hole of a core material having copper foil laminated on both top and reverse surfaces of the board is detected nondestructively and precisely.