Introduction Computer Numerical Control – CNC machines have become very popular in the past few days since they offer acceptable reputability of the machined parameters, allows many operations to be combined, allows machining in more than three axes, carries out the process with very little human intervention and a single operator can operate many machines. The paper provides an in-depth analysis of CNC machines and automated machining. Characteristics of CNC Machines A CNC machine, depending on the type may have two or more axis that can be controlled by a computer program. A CNC machine is defined as “A system in which the actions are controlled by direct insertion of data and the system must automatically interpret and carry out the instructions”. A dedicated computer is built into the control system of the machine and is connected to the servo controllers that provide motion to the machine axes. Based on the program written in G Codes, the axis would move to the new position at the required feed while the machine spindle would rotate at the specified cutting speed. Depending on the type of machine, the turret may have a number of tools that are fixed in special tool holders, and the distance from the tooltip to the spindle seating face is entered into the computer and this is called pre-setting. This distance is called the offset and the spindly axis will move back or forward to ensure that only the tooltip, tool sides are in contact with the faces to be machined. A CNC machine would have multiple programmable axes such as X, Y, and Z and in addition, the machine table which can be programmed to turn so that a fresh face is presented when required. By using proper tooling and design and depending on the number of setups required, it is possible to load more than one component on the different faces of the tooling. The machines can have two fixtures, one that is inside the machine with components and undergoing machines and the other outside so that un-machined components can be loaded and kept ready for the next cycle so that idle time is kept to a minimum (Pabla, 2007). CNC machines can also be integrated with CAD and CAM processes and it is possible to convert a CAD design into a programmable set of instructions so that the required dimensions can be machined. Primary processes and their characteristics CNC machines can be used for performing a number of operations such as milling, drilling, boring, tapping, reaming, spot facing, turning, EDM, grinding, and so on. Materials that can be machined include castings, forgings, bar stock material, roughing operations for dies and molds, stamping, drawing, plastic and wood components for prototyping, and so on. When it comes to CNC machines there is a different class of machines and these are designated as per the machining operations that they can carry out. The different primary processes are grinding, drilling, boring, milling, turning, EDM, drilling/ boring and tapping, metal spinning, deep drawing, and others. The different primary processes and the machine types are given in this section (Smid, 2005). CNC Turning CNC Turning machines are special types of lathes that are used to turn stock material, c