Punched-out ceramic green sheet and die null for ceramic green sheet punched-out

摘要

PURPOSE:To make a blanked ceramic sheet into a ceramic board which is extremely free from generation of breaking during transportation and conveyance in a process, by a method wherein a blanked ceramic green sheet whose corners of the side, top and bottom each are rounded off and the center of the side is expanded within a range of a specific length is fired. CONSTITUTION:Corners of the side 31, top 32 and bottom 33 each are rounded off, in a blanked ceramic green sheet 30. The center 34 of the side 31 is expanded within a range of up to 15mum. The reason why the center 34 of the side 31 is made within a range of up to 15mum is that when expansion of at least this range is desired, a clearance between a blanking die and punch becomes too microscopic. When the blanked sheet 30 is fired and made into a ceramic board, breaking during conveyance is hard to occur. Since blanking and end face processing are performed simultaneously, a production cost is low and a time also necessary for manufacturing can be reduced. Since processing of the surface is not performed after firing of the blanked sheet, a change in physical properties is not generated on a ceramic surface.