| 摘要 |
PURPOSE:To reduce the weight of a polygon mirror and to improve rapid rotational performance by constituting a peripheral edge part of Al or Al alloy, constituting a center part of Mg or Mg alloy and uniting these parts through a diffusion joined face. CONSTITUTION:A solid-like Mg alloy 1 heated to a temperature less than a melting point is continuously supplied to a guide tube 3 consisting of a heat insulating part by a pinch roll 7 through a water cooling part 8. The guide tube 3 is led into a furnace 4 stocking the molten metal 2 of Al alloy or the like and Mg alloy or the like 1 is brought into contact with the molten metal 2 of the Al alloy or the like in the vicinity of the outlet 4a of the furnace 4 and supplied to a water cooling mold 5 as a clad material with the Al alloy or the like. The water cooling mold 5 is formed like the shape of the polygon mirror, and while regulating the outline of an outer layer tube of the Al alloy or the like, cools the clad material. Since the contact faces 11 between the peripheral edge part 9 and the center part 10 are mutually diffused and joined, alloy formation can be attained and respective parts are united. Consequently, a lightweight polygon mirror excellent in rapid rotational performance can be obtained. |
