Advances in the Machining Finishing of Ceramic Composite Components for Aerospace Applications

Abstract

In general, ceramic materials have high thermomechanical strength at low density and offer high potential for lightweight applications in aerospace. Their advantages lie particularly in temperature ranges above 1000°C where alternative lightweight materials reach their limits of use. However, in many cases, their use in structural applications is prevented by their low fracture toughness and associated lack of damage tolerance. In addition, the existing manufacturing processes limit the freedom of design to simple geometric shapes. In contrast, 3D printed CMCs based on silicon carbide and short carbon fibers can offer higher functionality through more complex design options. 3D printed CMCs are therefore considered a key technology for high-temperature aerospace applications.

A further step towards increasing the potential applications of CMCs is to optimize the value chain for components with complex geometries. This article investigates a combination of near net shape manufacturing and machining finishing with the aim of finding suitable tool geometries for high surface qualities and minimal tool wear. Due to the high hardness of ceramic materials, machining today is usually performed using processes with geometrically undefined cutting edges, such as grinding. The PCD tools with geometrically defined cutting edges investigated in this article promise a significant increase in efficiency. The investigations focus on linear-orthogonal cutting tests on additively manufactured C/SiSiC workpieces with diamond tools of different macro cutting geometries. An additional increase in productivity is sought through the continuous recording and documentation of all process parameters and data, whereby deviations from the target state are to be detected, as early as possible.

Keywords: Milling, Ceramic, Diamond tool