A Fiber-Laser Process for Cutting Thick Yttria-Stabilized Zirconia: Application and Modeling

摘要

A novel laser processing technique is demonstrated for cutting up to 13-mm-thick sections of Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic. Y-TZP is a high toughness engineering ceramic, which is extremely difficult to machine in its final state. However for some applications, this is nevertheless desirable. As an example, Y-TZP-based dentures represent an example of mass-customization in which it is essential to machine the required shape from solid billets rather than to produce customized molds. Typically this is done mechanically and necessitates the use of diamond-tipped grinding and drilling tools;, however, this process is very slow and suffers from problems of high tool wear. In this work, an Ytterbium fiber laser system has been used to achieve full thickness cuts via a novel controlled crack propagation technique at substantially greater thicknesses than previously possible. The build up of heat and stress in the material during the cutting process is analyzed in a finite-element model and compared with experimental data. This illustrates the mechanism by which cracks are driven in a controlled way to generate a cut. Processing rates are substantially faster than alternative cutting techniques available for this material with feed rates of up to 1.8mm/s demonstrated.