A contribution to the study of the internal turning of hardened steels

Author(s)

Daniel Iwao Suyama

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica
• Defense date: 2014-07-15

Examining board members

Anselmo Eduardo Diniz; Amauri Hassui; Robson Pederiva; Alexandre Mendes Abrão; Reginaldo Teixeira Coelho

• Advisor: Anselmo Eduardo Diniz

Abstract

The machining of hardened materials with hardness over 45 HRC, emerges as an alternative to grinding in the 70s, with the commercial availability of Cubic Boron Nitride (cBN) tools. However, the low toughness of this type of tool makes it very sensitive to damage caused by vibrations, which are critical in the operations which the part or tool are susceptible to large deflections. This work aims to contribute to the study of vibrations in internal turning of holes in hardened AISI 4340 steel in finishing conditions. Different machining conditions and different tool holders (steel, carbide and equipped with particle damper) were tested. The surface finish, the acceleration (vibration) signals and tool wear of cBN inserts were evaluated. The results show that the vibration can take a secondary role in the surface finish, the machining with defined geometry tools can replace grinding in some cases, and the use of passive dampers can be a simple solution for machining longer holes (AU)

• FAPESP's process: 10/08457-1 - Analysis of tool's vibration in internal turning
• Grantee: Daniel Iwao Suyama
• Support Opportunities: Scholarships in Brazil - Doctorate