Although the NC machine tool also has the bed, column, guide rail, worktable, tool holder and other components of the ordinary machine tool, in order to match the high machining accuracy and high-speed cutting of the NC machine tool, the structural design of the host part of the machine tool also puts forward the requirements of high precision, high stiffness, low inertia, low friction, high resonance frequency and appropriate damping ratio, Therefore, there are significant changes in the structural design of the key components of NC machine tools compared with ordinary machine tools.

The main drive system realizes the cutting power required by various cutting tools and workpieces, and ensures constant power output within the rotating speed range as large as possible. At the same time, in order to enable the NC machine tool to obtain the best cutting speed, the main drive must realize stepless speed change in a wide range. The current CNC machine tools adopt high-performance DC or AC stepless speed regulation spindle motor, which is much simpler than the mechanical hierarchical variable speed transmission chain of ordinary machine tools. The accuracy, stiffness, vibration resistance and thermal deformation performance requirements of the spindle assembly that have a direct impact on the machining accuracy can be guaranteed through the structural design of the spindle assembly, reasonable bearing combination and the selection of high-precision special bearings. In order to improve productivity and automation, the chuck on the spindle has automatic clamping, loosening, chip cleaning and chuck quasi loosening mechanisms for cutting tools or workpieces. Recently, Japan has developed a new type of ceramic spindle with light weight and low thermal expansion. It is used in machining centers with high rigidity and precision.

The feed system of NC machine tool is driven by servo motor, which drives the tool or workpiece to complete the feed movement in each coordinate direction through ball screw. In order to determine the transmission accuracy and working stability of the feed system, the mechanical device is designed on the principle of low friction, low inertia and high stiffness. The specific measures are as follows: ① adopt low friction, light drag and high efficiency ball screw and linear rolling guide rail; ② The servo motor with large torque and wide speed regulation is directly connected with the lead screw to shorten and simplify the feed transmission chain; ③ Eliminate the transmission clearance of gear, lead screw and coupling through clearance elimination device; ④ Preload and stretch the rolling guide rail and lead screw.

The appearance of CNC machine tools mostly adopts the plate combined fully enclosed safety cover with simple line type, and is equipped with the operation panel integrating operation, display and control with modern characteristics, which eliminates all kinds of operation handles, hand wheels and polyhedral surface forms with complex and scattered line type of ordinary machine tools. The safety cover can prevent high-pressure and large flow coolant and iron filings from splashing, reduce dust intrusion, sound insulation and noise reduction, which is conducive to the accuracy maintenance and environmental protection of the machine tool, and truly reflects the characteristics of mechanical, electrical and hydraulic integration; Advanced numerical control digital display device; There are strict requirements for the accuracy and stiffness of the machine tool, reliability, safety protection and environmental protection; Adopt advanced standard tool system and automatic tool change device with reasonable installation position; Adopt a complete set of commercialized and standardized new accessories, automatic chip removal, lubrication and cooling devices, etc. The desktop or suspended CNC operation panel designed according to the principle of ergonomics is the only interface for the contact and information exchange between the machine tool and the operator. The design of indicator light, button and key arrangement is not only suitable for human operation characteristics, but also conducive to the coordination and communication between man and machine. Through good visual key surface color and standardized pictographic symbols, It can accurately reflect and transmit the information between the two. In addition, the touch screen operation makes the man-machine interface more friendly, and the dynamic real-time display of the processing process makes the processing process more intuitive and easier to operate.

● NC device is the core of NC machine tool, including hardware (printed circuit board, CRT display, key box, paper tape reader, etc.) and corresponding software. It is used to input digital part program, complete input information storage, data transformation, interpolation operation and realize various control functions.

● driving device, which is the driving part of the actuator of NC machine tool, including spindle driving unit, feed unit, spindle motor and feed motor. He realizes spindle and feed drive through electrical or electro-hydraulic servo system under the control of NC device. When several feeds are linked, the machining of positioning, straight line, plane curve and space curve can be completed.

● auxiliary devices, some necessary supporting parts of index control machine tool, to ensure the operation of NC machine tool, such as cooling, chip removal, lubrication, lighting, monitoring, etc. It includes hydraulic and pneumatic devices, chip removal devices, exchange worktables, CNC turntables and CNC indexing heads, as well as cutting tools and monitoring and detection devices.

● programming and other auxiliary equipment can be used to program and store parts outside the machine. It is not only an important part of mechatronics, but also an important symbol of the technical level of modern machine tools.

Generally speaking, CNC boring and milling machine with automatic tool exchange device (ATC) is called machining center. It can carry out milling, boring, drilling, expanding, reaming, tapping and other processes. The grinding function cannot be included because fine abrasive particles may enter the machine tool guide rail, thus damaging the accuracy of the machine tool. There are special protective measures on the grinder. Machining centers can be divided into vertical machining centers and horizontal machining centers. The vertical spindle is vertical and the horizontal spindle is horizontal.

CNC machine tool is the product of comprehensive application of high and new technologies such as computer automatic control, automatic detection and precision machinery. It is a typical mechatronics processing equipment with high technology intensity and high degree of automation. Compared with ordinary machine tools, its advantages are obvious. It not only has high machining accuracy, stable product quality, but also has a high degree of automation, which can reduce the physical labor intensity of workers and greatly improve the production efficiency. In particular, it is worth mentioning that NC machine tools can complete the machining of complex curved parts that are difficult or impossible to be machined by ordinary machine tools, Therefore, the position of CNC machine tools in mechanical manufacturing industry is becoming more and more important. CNC machine tool embodies the mainstream of the current world machine tool technology progress. It is an important index to measure the level of mechanical manufacturing process. It plays an important basic and core role in advanced manufacturing technologies such as flexible production and computer integrated manufacturing. Therefore, how to better use CNC machine tools is a very important problem.