Computer numerical control (CNC) machining is an essential manufacturing technology in modern industry, playing a vital role in the manufacture of key components in a variety of fields, such as energy, power, national defence, vehicles, and aerospace, among others. In these fields, the requirements of high-end equipment are strict, meaning that a large number of precise and complex curved parts with considerable machining difficulty and tight performance tolerances have emerged. The machining requirements for these parts have been evolving from simple shape and position accuracy in the past towards high performance of the machined parts. This brings severe challenges for traditional CNC machining theory and methods for complex curved parts.

CNC machining processes are driven directly by the locus of a cutter, therefore, efficiently generating a tool path becomes essential. However, most methods plan tool paths only from a geometric point of view, ignoring the influence of the kinematic performance of machine tools on tool paths. Another challenge in CNC machining is the detecting and subsequent elimination or reduction of machining error, and to combat this, the ability to simulate exactly the machining process with proper mathematical models is essential. Simultaneously, keeping the machining process stable is vital for maintaining workpiece accuracy and improving efficiency. Theories of chatter and corresponding depressing methods are necessities for preserving stability. Deformation in machining processes is still a major resource of machining error, and so controlling the deformations of walls or tools is an important area of research. Recently, robot machining technology has become the subject of increasing attention, due to the ability to reach inaccessible areas of complex parts and the reduced workspace requirements. However, the low structural stiffness when compared to a traditionally designed machine tool is a major drawback, restricting its use in high force machining applications such as milling and drilling. Therefore, the development of theories to control robot machining processes is an important challenge.

The aim of this Special Issue is to provide a platform for work addressing the challenges in meeting the demand for extreme performance and machining theory/technology, benefitting both researchers and manufacturers. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• Machining dynamics, stability prediction, and chatter suppression theory/technology
• Tool path design and optimisation theory/technology
• Computer-integrated machining theory
• Mechanical behaviour of processing systems
• Deformation and compensation in the machining process
• Machining error and corresponding depressing error theory/technology
• Robot machining theory/technology
• Simulation theory/technology using finite element methods (FEM)
• Surface-integrity control theory/methods/technology
• Computer-aided design theory/methods