Thoughts related to CNC machine tools

Abstract: This article first describes the advantages and disadvantages of CNC machine tools, and then elaborated on the types of CNC machine tools, and finally that the CNC control technology and CNC machine tool control technology trends.

Keywords: CNC machine tool control technology

CNC machine tools is a typical mechatronics product, CNC control technology is a Computer and software technology, automatic control technology, electronics technology, automatic detection technology, hydraulic and pneumatic technology and precision machinery technology as one of the multidisciplinary integrated technology With the rapid development of science and technology, the rapid development of mechatronics, CNC machine tool widely used in business, production line operators on the knowledge and capacity requirements higher and higher.


First, the advantages and disadvantages of CNC machine tools

(A) the advantages of CNC machine tools
The adaptability of the parts, surface parts of complex shape can be processed in the same CNC machine tools, simply replace the processing program, you can adapt to different varieties and sizes of the workpiece automatic processing, which is a complex structure of the single, small mass production and trial of new products provide a great convenience, especially for those hard to ordinary machine processing or not processing of sophisticated surface (such as the spiral surface), CNC machine tools can be automatically processed.

High precision, processing quality and stability now, and CNC machine tool control table minimum amount of movement (pulse equivalent) common to 0.0001mm, and numerical control system can automatically compensate for the feed drive chain backlash and lead screw pitch error, CNC machine tools to achieve high precision. In addition, the manufacture of high precision CNC machine tools, the automatic processing methods to avoid the producer's human operator error, therefore, consistent with a good number of the workpiece size, high rate of qualified products, processing quality stable.

Production efficiency due to structural rigidity CNC machine tools, allows for powerful cutting a large amount of cutting, from the spindle speed and feed rate of change in scope than the ordinary machine tool large, so the choice of the best in the processing cutting, CNC machine tools to improve the cutting efficiency, saving maneuver time compared with ordinary machine tools, CNC machine tool production efficiency can be increased 2-3 times.

Good value for money using CNC machine tools for single-piece, small batch production, it can save hours of work crossed to reduce the adjustment process and testing time, saving the direct production costs, while saving tooling design, manufacturing costs, CNC machining high precision, stable quality, reduce scrap rates, production costs decline further. Additionally, CNC machine tools can achieve more than one machine, CNC machine tools while prices so high, can still get good value for money.

High degree of automation. CNC high degree of automation can greatly reduce the labor intensity, reduced the number of operators, is also conducive to modern management, to more advanced manufacturing system development.


(B) the shortcomings of CNC machine tools
The main disadvantage of CNC machine tools are as follows: higher prices, a large investment in equipment for the first time, the operation and maintenance personnel the technical requirements of high processing complex shape parts. Manual programming of the workload.


Second, the type of CNC machine tools

Many different types of CNC machine tools, following major categories:
Use by process category. By use of technology, CNC machine tools can be categorized as follows ordinary CNC machine tools: the classification and the classification of general machine tools like milling machines, CNC anchor bed, CNC drilling, CNC grinding machines, CNC gear cutting machine tools, etc. processing center machine tools: CNC machining center is in the general installation of a CNC machine tool magazine and automatic tool consisting of CNC machine tools, clamping it in a variety of processes after the process.

Classified according to movement pattern. By sport, and CNC machine tools can be categorized as follows: point and control of CNC machine tools. CNC system controls only the tool from the need CNC drilling machines, CNC coordinate hammer bed, CNC punching bed. Linear control of CNC machine tools: CNC In addition to controlling between points outside of the exact location, but also to ensure that the trajectory of moving between two points is a straight line, but also the speed of movement control. Such tools are simple CNC lathe, CNC marketing, milling, etc. contour control of CNC machine tools: CNC system can coordinate two or more movement and speed of displacement related to continuous control, the trajectory synthesis process to meet requirements and such machines are CNC lathes, CNC milling machine and so on.



Links to free download http://www.hi138.com Servo control system according to classification according to servo control systems, CNC machine tools can be categorized as follows open-loop control system of CNC machine tools. Closed-loop control system of CNC machine tools. Semi-closed loop control system of CNC machine tools.

Function of the system according to the level of numerical classification level of classified technical capabilities, CNC system can be categorized as follows economic CNC machine tools. Economy refers to the use of CNC machine tools are mostly open-loop control system of CNC machine tools are cheap, suitable for automation is not critical . mid-range of CNC machine tools and such features than the full CNC machine tools, affordable and used widely. high-end CNC machine tools. this type of CNC machine tools featured, more expensive.

Third, the development of CNC machine tool control technology

Machinery and equipment control device is the first manual controller present, the relay - contactor control machinery and equipment in China is still the most basic form of electrical control one of the 20th century milk years to 50 years, there has been cross-magnetic amplifier - motor control, which is a closed loop feedback system, the system control precision and rapidity have been improved .20 1960s appeared transistor - thyristor control, powered by the thyristor DC drive systems and AC transfer transporting speed system not only greatly improved performance and reduced mechanical equipment and floor space, power consumption, efficiency Bureau, completely replaced the cross magnetic amplifier - motor control system.

60 years in the 20th century there a way to the small changes needed to easily control program, simple, inexpensive automated devices - the order of the controller. LSI and microprocessor technology with the development and application, 20 1970s with the emergence of a new type of microprocessor core industrial controller - programmable logic controller. This device is fully able to adapt to harsh industrial environments, because it has a Computer control and relay control systems of both worlds, it has been standardized as an ordinary general-purpose equipment used in industrial control.

With the rapid development of Computer technology, CNC machine tools has been used widely, well to further promote the development of a numerical control system, resulting in automatic programming systems, Computer numerical control systems, Computer systems and the nature of group control manufacturing systems Computer integrated manufacturing systems and computer-aided design, manufacturing integration is the integration of advanced stage machinery, enabling the product from design to manufacture fully automated.

In summary, the generation of machine control technology, not isolated, but the result of mutual penetration of various technologies which represent the emerging new generation of production technology, has demonstrated and will increasingly show powerful.


Fourth, the CNC control technology trends

The development of production technology, increasing performance requirements, frequent product modifications, using many varieties of small batch production methods more and more enterprises, which requires the high-speed CNC machine tools, tactics degree, complex, systematic and intelligent development.

High-speed and high precision. CNC intelligent information. Opening of the CNC system.

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