| 摘要 |
PURPOSE:To prevent local concentration of stress and to decrease the deformation during boring by fixing the outside peripheral edge of a perforated plate to be worked by high-rigidity fixing plates, providing slits to the periphery of the perforated plate and exerting tension in the direction of the outside peripheral edge. CONSTITUTION:The front and rear surfaces on the outside peripheral edge of the perforated plate 1 are grasped respectively by the fixing plates 5 and 6. The outside periphery of the perforated plate 1 are fastened and fixed by the fixing plates 5 and 6 by means of bolts and nuts 7. The slits 8 or clearance holes are provided to the periphery of the perforated plate 1 and thereafter, heat energy is irradiated thereto to bore holes, then the generated stress and strain are relieved by the slits 8. Eccentric bolts 10 are inserted into holes 9 to be inserted with the bolts and nuts 7 and the strain is forcibly exerted to the perforated plate 1 to be worked by acting the tension in the outside peripheral direction of said plate, then the boring is executed in the state of maintaining the plane of the perforated plate if the perforated plate to be worked has many microholes 4. The perforated plate is put into an annealing furnace after the boring and is subjected to a stabilization heat treatment by which the internal strain is relieved. |
