Surface finish and edge preparation of Al₂O₃ + MgO cutting inserts by grinding and their application in hard turning

Author(s)

Nardy, Maysa Freitas Mainardes ; de Souza, Jose Vitor Candido ; dos Santos, Sergio Francisco ; de Sampaio Alves, Manoel Cleber ; Ribeiro, Marcos Valerio ; Antonialli, Armando italo Sette ; Ventura, Carlos Eiji Hirata

• Document type: Journal article
• Source: INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY; v. 134, n. 1-2, p. 13-pg., 2024-07-25.

Abstract

Due to their high hardness at elevated temperatures and chemical stability, alumina-based ceramic cutting tools have been successfully applied in the machining of ferrous materials, especially quenched and tempered steels. Their low fracture toughness, however, makes it difficult to finish them by grinding, as cracks and defects can occur. In addition, its application in machining processes demands appropriate edge preparation to avoid tool failure. Within this context, the paper aims to demonstrate the applicability of an experimental Al2O3 + MgO ceramic cutting insert in hard turning. For this, grinding tests were performed to determine the most appropriate conditions to improve its surface and edge quality. The effects of cutting and feed speeds, grinding wheel bonding material, and abrasive grain size were investigated. Moreover, different cutting-edge geometries were prepared in this tool material and tested in turning a hardened AISI 4140 steel (50 HRC) to determine their performance regarding tool life and workpiece roughness. The results demonstrated that a finer grinding wheel (D15) combined with high cutting (60 m/s) and feed (10 mm/min) speeds leads to the lowest surface roughness and edge chipping. In addition, both symmetric (Kappa = 1) and asymmetric (Kappa = 2) edge roundings led to higher tool lives in hard turning in comparison to a single chamfered tool, as they contributed to better load distribution in the cutting region. The paper provides information for the manufacture and application of alumina-based ceramic cutting inserts in the metalworking industry, as it disseminates good manufacturing practices and recommendations for appropriate cutting-edge geometry. (AU)

• FAPESP's process: 15/15622-2 - Influence of grinding parameters in the manufacturing of cemented tungsten carbide inserts on their performance in turning of a titanium alloy
• Grantee: Carlos Eiji Hirata Ventura
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 17/12304-5 - Multi-user equipment approved in grant 15/15622-2: CNC grinding machine for cutting insert preparation
• Grantee: Carlos Eiji Hirata Ventura
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 17/12309-7 - Multi-user equipment approved in grant 15/15622-2: microscope for three-dimensional image analysis
• Grantee: Carlos Eiji Hirata Ventura
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 18/24614-1 - Plan of Implementation of the Year 2018 Technical Reserve Parcel (Base 2017) for Infrastructure Institutional Costs Center for Physical Sciences and Technology (CCET) UFSCAR
• Grantee: Luiz Fernando de Oriani e Paulillo
• Support Opportunities: Research Grants - Technical Reserve for Institutional Research Infrastructure