A contribution to the study of titanium alloy milling: tool life, cutting forces and workpiece roughness

Author(s)

Henrique Kull Neto

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica
• Defense date: 2013-02-14

Examining board members

Anselmo Eduardo Diniz; Robson Pederiva; Marcio Bacci da Silva

• Advisor: Anselmo Eduardo Diniz

Abstract

Titanium and its alloys are known as difficult to machine materials because of their unique combination of properties, such as high strength at elevated temperatures, low thermal conductivity, high chemical reactivity with almost all tool materials and low modulus of elasticity (which favors vibration). Because of the high tendency of vibration in titanium milling, it is necessary to keep vibration under control in order to achieve high productivity. This work focused on the study of tool life, cutting forces and work piece roughness in the end milling of Ti-6Al-4V alloy. The main objectives were to find a tool holder material that provides reduction of vibration in the milling process, increasing tool life, and to find cutting parameters (cutting speed and feed per tooth) that provide longer tool lives. The bored tool holder and the tool holder filled with polyurethane exhibited higher natural frequency. However, it was noticed a decrease in the tool holder stiffness, which caused variation of cutting force and higher axial load. Results showed that at low cutting speeds (with low cutting frequency), tool holder deflection is the main factor affecting tool life and, therefore, the bored and the polyurethane filled tool holders generated shorter tool lives than the commercial tool holders of steel and cemented carbide. Attrition was the main wear mechanism in all tests. The influence of cutting speed, feed per tooth and tool holder material (steel and cemented carbide) on the tool life (measured in terms of volume of chip removed per cutting edge) was analyzed. It could be seen that the only parameter which had any influence on tool life was the cutting speed (AU)

• FAPESP's process: 11/02129-5 - Study of vibration when milling titanium alloy
• Grantee: Henrique Kull Neto
• Support Opportunities: Scholarships in Brazil - Master