Design and fabrication of an aluminium oxide cutting insert with an internal cooling channel

Abstract

This paper presents the design and fabrication of an aluminium oxide cutting insert with an internal cooling channel formed through an additive manufacturing method. The formed insert is subjected to a controlled densification process and analysed through a series of characterisation investigations. The purpose of the study is to develop the design concept and analyse the forming and sintering parameters used in the lithographic ceramic manufacturing process. The results validated the feasibility of the geometrical design, providing the required structural conformity with the integrated internal feature using conditional specifications. It is confirmed that the forming parameters would affect the material properties of the green body. Furthermore, the results indicate that the heating rate and temperature variance of the de-binding and thermal treatment regime influences the microstructural growth kinetics and the quality of the densified insert. Using a novel application of liquid gallium as an internal coolant, experimental results showed a decrease in tool wear difference of 36% at \(V_{{\text{c}}}\) = 250 m/min, and 31% in tool wear difference at \(V_{{\text{c}}}\) = 900 m/min between cooling and non-cooling conditions. When external cooling was applied, the results showed at \(V_{{\text{c}}}\) = 250 m/min, the difference between the tool wear rates with the internal coolant relative to the external coolant was 29%. Increasing to \(V_{{\text{c}}}\) = 900 m/min, the results revealed a 16% tool wear difference. The results clearly indicate the potential of liquid gallium as a heat transfer agent in internal cooling applications for cutting inserts, and by extension demonstrable reduction in tool wear.