PRODUCTION OF POLYGON MIRROR

摘要

PURPOSE:To obtain the method for producing the polygon mirror having the reflection efficiency having no problems in practicable use at a low cost by using low-impurity aluminum as a material without using high-purity aluminum as the material of the polygon mirror. CONSTITUTION:The low-purity aluminum 1 melted at 700 to 720 deg.C is dropped by gravity through a sprue 2 having an outlet of a polygonal sectional shape and is rapidly cooled by cooling water 3 at the point where the aluminum of the material emerges from the sprue 2, by which the polygonal columnar aluminum blank material 4 having a fine metallic crystal part of 100 to 300mum crystal structure size formed on the rapidly solidified layer of the surface is produced. The polygon mirror is produced by precision closed forging from such polygonal columnar aluminum blank material 4.