At present,the world's advanced manufacturing technology is constantly emerging,the application of ultra-high-speed cutting,ultra-precision machining and other technologies,the rapid development of flexible manufacturing systems and the continuous maturity of computer integrated systems,put forward higher requirements for CNC machining technology.In order to adapt to this situation,CNC machine tools are developing in the following aspects.High speed,high precision speed and precision are two important indicators of CNC machine tools,which are directly related to processing efficiency and product quality.
At present,the numerical control system uses a processor with a higher number of bits and a higher frequency to improve the basic operation speed of the system.At the same time,the use of ultra-large-scale integrated circuits and multi-microprocessor structures to improve the data processing capabilities of the system,that is,improve the speed and accuracy of the interpolation operation.The linear servo feed mode of the machine table is directly driven by a linear motor,and its high speed and dynamic response characteristics are quite superior.The feedforward control technology is used to greatly reduce the tracking hysteresis error,thus improving the machining accuracy of corner cutting.
In order to meet the requirements of ultra-high-speed machining,the CNC machine tool adopts a structural form in which the spindle motor and the machine tool spindle are combined into one,which realizes the integration of the variable frequency motor and the machine tool spindle.The bearing of the spindle motor adopts a magnetic floating bearing,a hydrodynamic bearing or a ceramic rolling bearing.form.Ceramic knives and diamond coated tools are now available.
Multi-functional machining centers equipped with automatic tool changers(tool magazine capacity up to 100 or more)Various machining centers equipped with automatic tool changers can simultaneously perform milling,boring and drilling on the same machine Cutting,turning,reaming,reaming,tapping and other processes,modern CNC machine tools can use multi-spindle and polyhedral cutting,that is,different parts of a part can be cut in different ways at the same time.Due to the multi-CPU(computer center processing device)structure and the hierarchical interrupt control method,the CNC system can simultaneously process and program on the same machine to realize the so-called“foreground processing,background editing”.In order to meet the requirements of flexible manufacturing systems and computer integrated systems,CNC systems have long-distance serial interfaces,and even can be networked to realize data communication between CNC machine tools,and can also directly control multiple CNC machine tools.
Introducing adaptive control technology Intelligent modern CNC machine tools will introduce adaptive control technology,automatically adjust the working parameters according to the changes of cutting conditions,so that the best working condition can be maintained during the machining process,thus obtaining higher machining accuracy and better Surface roughness also increases tool life and equipment productivity.With self-diagnosis and self-repair function,the system performs self-diagnosis and inspection on the CNC system itself and various devices connected to it at any time during the whole working state.In the event of a fault,immediately take measures such as shutdown,and perform a fault alarm to indicate the location and cause of the fault.The faulty module can also be automatically taken offline,and the standby module can be turned on to ensure the requirements of the unmanned working environment.In order to achieve higher fault diagnosis requirements,the trend is to use artificial intelligence expert diagnostic systems.
The CNC system will use a more integrated circuit chip,using large-scale or ultra-large-scale dedicated and hybrid integrated circuits to reduce the number of components to improve reliability.Through the hardware function software to adapt to the requirements of various control functions,the modularization,standardization,generalization and serialization of the machine structure of the hardware structure are adopted,which not only improves the hardware production batch,but also facilitates the organization of production and quality control.It can also automatically diagnose and alarm the hardware,software and various external devices in the system by automatically running various diagnostic programs such as diagnostics,online diagnosis and offline diagnosis.Use alarm prompts to eliminate faults in a timely manner;use fault-tolerant technology to adopt“redundant”design for important components to achieve fault self-recovery;use various testing and monitoring technologies,when production over-travel,tool damage,interference,power failure,etc.When an accident occurs,the corresponding protection is automatically performed.
CAD/CAM graphic interactive automatic programming has been widely used
This is a new trend in the development of CNC technology.It is a part processing drawing drawn by CAD,and then calculated and post-processed by the tool path data in the computer,thereby automatically generating NC part processing program to realize the integration of CAD and CAM.With the development of CIMS technology,there is a fully automatic programming method of CAD/CAPP/CAM integration.The biggest difference between it and CAD/CAM system programming is that the processing parameters required for programming do not have to be manually involved,directly from the system.Get the CAPP database.
The control system and the numerical control system miniaturized control system and the miniaturization of the numerical control system facilitate the integration of the machine and the electric device.At present,it mainly adopts ultra-large-scale integrated components and multi-layer printed circuit boards,and adopts a three-dimensional installation method to enable high-density installation of electronic components,and to reduce the occupied space of the system by a large scale.The replacement of the conventional cathode ray tube with a new type of color liquid crystal thin display will further miniaturize the numerical control operating system.This makes it easy to install it on machine tools,making it easier to use the CNC machine.