CNC machine tools: The core force driving manufacturing with precision

From the curved surface processing of aero engine blades to the precision cylinder block manufacturing of automotive engines, from the microstructure grinding of chip packaging bases to the high-precision turning of high-speed rail wheel axles, all processing scenarios in modern manufacturing that have requirements for precision, efficiency and complexity cannot do without the support of CNC machine tools. As a modern production equipment that combines numerical control technology with traditional machine tools, numerical control machine tools automatically control the processing actions and paths of the machine tools through preset programs, making high-precision batch processing of complex parts possible. It is undoubtedly the "mother machine of industry" in modern manufacturing. Its technological level and industrial scale directly determine the core competitiveness of a country's manufacturing industry.

Core technologies and key parameters: The core indicators that determine processing capabilities

The performance of CNC machine tools is jointly determined by technical parameters and core configurations. Different parameters correspond to the requirements of different processing scenarios and also determine the application boundaries of the equipment

Core processing parameters

Maximum processing size It is the most fundamental parameter of a CNC machine tool, referring to the maximum size range of the workpiece that the equipment can process. Taking the common vertical machining center as an example, the stroke parameter is usually expressed by the maximum movement distance of the X, Y, and Z axes. For the VMC850 model, the X stroke is 800mm, the Y stroke is 500mm, and the Z stroke is 500mm. It can meet the processing requirements of the vast majority of small and medium-sized mechanical parts. The travel range of the gantry machining center can reach several meters, and it can process super-large workpieces such as wind turbine blades and large ship components. Band saw machines, as CNC machine tools for blanking, are usually classified by the maximum diameter of round and square materials they can cut, ranging from 300mm to 1500mm, to meet the cutting requirements of raw materials of different sizes.

Machining accuracy: It is a core performance indicator of CNC machine tools, usually divided into positioning accuracy and repeat positioning accuracy. The positioning accuracy of ordinary economic CNC machine tools is about 0.01mm, while high-end precision CNC machine tools can reach the 0.001mm level, which is equivalent to one eightieth of the diameter of a human hair. Take the No. 4/5 CNC turret milling machine of Zaozhuang Luji CNC as an example. The spindle runout is controlled at 0.005 millimeters, and the parallelism of the worktable movement in the X-axis direction is only 0.02 millimeters, which is sufficient to meet the strict precision requirements of mold processing and precision parts.

Spindle parameters: The spindle speed range and output power determine the processing capacity of the machine tool. The spindle speed range for ordinary processing is usually between 0 and 8000rpm, while for high-speed processing, it can reach tens of thousands of RPM, which can meet the high-speed cutting requirements of light metals such as aluminum and copper, as well as composite materials such as acrylic and carbon fiber. The output power of the spindle determines the hardness of the material that can be processed. A high-power spindle can easily handle the cutting processing of high-strength materials such as hardened steel and stainless steel.

Core system and structural configuration

The numerical control system is the "brain" of a CNC machine tool, responsible for processing processing instructions and controlling the movement trajectories of each axis. Currently, the mainstream numerical control systems are divided into two major categories: imported and domestic. Imported brands have advantages in stability and precision retention, while domestic systems have more advantages in cost performance and localized services. In recent years, with technological progress, Domestic numerical control systems have gradually expanded from the low-end market to the mid-to-high-end market, achieving a gradual replacement of imported products.

Structural rigidity is the core foundation of machine tool reliability. Machine tools with a bed of integral casting structure have much better rigidity than those with welded structures. When processing heavy materials, they are less likely to vibrate, which not only ensures processing accuracy but also extends the service life of vulnerable parts such as saw blades and cutting tools. The emergence of electric spindle technology has simplified the structure of five-axis linkage machine tools, reduced manufacturing difficulty and cost, and promoted five-axis linkage processing technology to gradually move from the high-end military field to ordinary civilian manufacturing.

Main categories and typical application fields

According to different processing methods and functions, CNC machine tools can be classified into multiple categories. Each category corresponds to different application scenarios, covering almost all processing demands in the manufacturing industry.

Machining centers and milling machines

Machining centers are the most commonly used category of CNC machine tools, which are classified into multiple types such as vertical, horizontal, gantry, and five-axis linkage. They are mainly used for processing planar, grooved, and curved surface structural parts and are widely applied in fields such as mold manufacturing, aerospace parts, and automotive components. Among them, the five-axis linkage machining center is one of the most technically challenging categories. It can achieve one-time processing of complex three-dimensional surfaces, and the surface finish of the processed parts is higher. The processing speed is more than twice that of traditional three-axis machine tools. It is an indispensable core equipment in the aerospace and new energy vehicle fields.

CNC lathes and turning centers

CNC lathes are mainly used for processing rotary parts such as shafts and discs. They are one of the most widely used types of CNC machine tools at present. They are divided into two structures: flat bed and inclined bed. Inclined bed CNC lathes have more advantages in chip removal and precision stability. They are mainly used for batch processing of automotive half shafts, motor shafts, and valve parts. Turning centers can also integrate milling functions. Realize the compound processing of turning and milling, and complete all processing procedures with one clamping, further improving the processing accuracy and efficiency.

CNC band saw machine

The CNC band saw machine is a core CNC equipment in the field of metal blanking. It controls fixed-length feeding and automatic cutting through a CNC system and is widely used in the raw material blanking process of industries such as mechanical manufacturing, automotive parts, and mold manufacturing. It can automatically complete cutting according to set parameters, with high cutting accuracy and small deformation, saving a lot of processing costs for subsequent fine processing. According to different application scenarios, it can be divided into various structures such as horizontal, vertical, and double-column. The double-column structure band saw machine has stronger rigidity and is suitable for cutting large-sized and heavy materials.

In practical applications, over 85% of mechanical parts in China are processed on CNC machine tools at present, and CNC technology has permeated every sub-sector of the manufacturing industry: The aerospace industry requires five-axis linkage CNC machine tools to process precision components with complex structures. The automotive manufacturing industry needs a large number of CNC lathes and machining centers to process various parts. The mold manufacturing industry needs high-precision CNC milling machines to process mold cavities. The construction machinery industry needs large-sized band saws and gantry machining centers to process large structural components. Even in the field of vocational education, Stable and easy-to-operate CNC machine tools are also needed as teaching and training equipment.