Classification of CNC Machine Tool

　　The characteristics of a CNC Machine Tool include high machining accuracy and excellent product quality stability; high production efficiency; a high degree of automation and low labor intensity; yet it features complex control and high maintenance costs. CNC Machine Tools are generally used for parts requiring high precision and mass production. The structural design of CNC Machine Tools incorporates necessary measures and reflects the integration of mechanical and electrical components. First, the structure introduces ball screw-nut mechanisms and various backlash-compensation designs to minimize errors in mechanical transmission as much as possible. Second, software-based precision compensation techniques are employed to further reduce mechanical errors. Third, processing is controlled by programs, thereby reducing the impact of human factors on machining accuracy. These measures not only ensure high machining accuracy but also maintain outstanding quality stability. So, how are CNC Machine Tools classified?

　 　I. Classification of CNC Machine Tool by Processing Technology:

　　(1) General-purpose CNC Machine Tool. This type of machine tool, like traditional general-purpose machine tools, includes CNC lathes, milling machines, boring machines, drilling machines, grinding machines, and more. Moreover, each type comes in many varieties—for example, among CNC milling machines, there are vertical milling machines, horizontal milling machines, tool milling machines, and gantry milling machines. The process capabilities of these CNC machine tools are similar to those of general-purpose machine tools; the key difference is that they can machine parts with complex shapes.

　　(2) Multi-axis CNC Machine Tool. For some parts with complex shapes, even a three-axis CNC Machine Tool cannot handle the machining—for example, propellers or curved surface parts of aircraft. These require composite motions involving three or more axes to achieve the desired shape. As a result, multi-axis CNC Machine Tools have emerged. Their defining characteristic is that the CNC controller manages a greater number of axes, and their machine tool structures are relatively complex. The number of coordinate axes typically depends on the process requirements for the parts being machined. Currently, 4-, 5-, and 6-axis CNC Machine Tools are commonly used.

　　(3) CNC Machine Tool with Machining Center Function. This type of machine tool has evolved from the conventional CNC Machine Tool. It is constructed by adding a tool magazine (capable of holding more than 10 to over 100 tools) and an automatic tool-changing device to a standard CNC Machine Tool, thus becoming a CNC Machine Tool equipped with an automatic tool-changing device (also known as a multi-process CNC Machine Tool or a boring-and-milling-type machining center; commonly referred to simply as a Machining Center). This further advances the CNC Machine Tool toward greater automation and higher efficiency.

　　The difference between a CNC Machining Center and a conventional CNC Machine Tool is that, after the workpiece is clamped once, the CNC system can automatically control the machine tool to change tools, continuously performing multiple machining operations—including milling (turning), boring, drilling, reaming, and tapping—on all machined surfaces of the workpiece. Most of these machines are primarily geared toward boring and milling, and they are mainly used for machining box-type parts. Compared with conventional CNC Machine Tools, they offer the following advantages:

　　① Reducing the number of machine tools simplifies management. For parts requiring multiple machining operations, a single machine tool can complete all processing steps, thereby reducing the inventory of semi-finished products.

　　② Since the workpiece requires only one clamping, positioning errors caused by multiple setups are reduced, allowing machining quality to be ensured solely by the machine tool’s precision.

　　③ Process concentration reduces auxiliary time and improves productivity.

　　④ Since multiple machining operations can be completed in a single setup on one machine tool, the number of specialized fixtures and jigs is significantly reduced, further shortening the production preparation time.

　　Due to the numerous advantages of CNC Machine Tool, it is highly popular among users and thus occupies a very important position in CNC Machine Tool production.

　　Another type of machining center is developed on the basis of lathes and is primarily used for machining shaft-type parts. In addition to turning and boring operations, these centers can also perform drilling, milling, and tapping at arbitrary locations on both end faces and circumferential surfaces. Such machining centers are equipped with a tool magazine that can hold between 4 and 12 tools. These machines are commonly referred to as turning centers (TC: Turning Center).