| 摘要 |
PURPOSE:To improve the life and working efficiency of a forming tool by chamfering the outside corner parts of small ceramic nib pieces for said tool to provide a clearance between the hole of nib holding members and the corner part thereby avoiding stress concentration during working. CONSTITUTION:Plural small ceramic nib pieces 22 having a trapezoidal cross section are combined and nibs 16, 18 having an inside hole for working with a polygonal cross section are formed. The nibs 16, 18 are fitted into the hole of nib-holding members 10, 20. The outside corner part 30 of each piece 22 mentioned above is rounded to form a clearance 32 between the part 30 and the hole of the member 20. Stress concentration during working is averted by such tool and the life and working efficiency of the tool are improved. |
