CNC machine tools Generally control the media, digital devices, servo systems, and body composition machine. The figure of the solid line shows the open loop control block diagram of CNC machine tools.

CNC Machine diagram Order to improve the precision machine tools, then add in the system, a measuring device (the picture above the dotted lines), thus constitutes a closed-loop control block diagram of CNC machine tools. Open-loop process control system works like this: to control the machine table movement displacement, displacement velocity and displacement direction, the displacement trajectory and other parameters by controlling the media input device to the CNC, CNC equipment orders based on these parameters are calculated into the to the pulse sequence (including the above four parameters), and then amplified by the servo system conversion, the final control table according to the required speed, trajectory, direction and distances. If the closed-loop system, then enter the command value, while the real feedback detection tool bench who is wrong between the value of international displacement, feedback capacity with the input numerical control device in comparison, if the difference shows that the second difference, then Control of NC machine tool equipment toward the elimination of errors of direction.

Components will now be summarized as follows:

1, control media CNC machine work, do not need workers to operate machines shake the handle, but also the intent to automatically implement it, which must be established between the NC machine tool and a link, this link on a medium customarily termed to control medium (or media program, enter the media, information carrier).

Used to control the standard media is perforated with 8 units, and is commonly used with perforated paper, so called tape. The width of 25.4mm, thickness 0.108mm, each line must have a 1.17mm in addition to synchronization of holes, the maximum of information with 8 1.33mm hole. 8 holes per row with or without the permutations and combinations to represent different code (tape on the provisions of the hole configuration, as code). The perforation with input to the numerical control device reading machine, then read the perforated belt with machine code can be converted into numerical control devices to identify and deal with the electrical signal and sent to the CNC device to will complete the order information input work.

2, Control Unit Numerical control device is the hub of CNC machine tools, CNC machine tools in general are generally input devices, memory, controller, component operation and output devices. Numerical control device to receive input media information, and to identify its source, storage, computing, the corresponding output pulse to drive the servo system command, then control the machine movements. Computer numerical control machine tools, because the computer itself with computing devices, controllers, etc. The unit, so the role of NC devices by a computer to complete.

3, servo system Servo system is the role of the pulse signal from the CNC device is converted to machine the movement of moving parts, so that table (or slide board) precise positioning or be strictly in accordance with the provisions of the trajectory of relative motion, the final processing of the line drawings required parts.

In CNC machine tool servo system, servo drive components are commonly used in stepper motor power, electro-hydraulic pulse motor, DC servo motor and servo motor.

4, machine tools

NC machine tool, the use of a common tool in the initial stage, only in automatic transmission, bench knife or automatic indexing and the handle makes some changes. Proved: CNC machine tools except as cutting large, continuous machining accuracy of workpiece heat affected more than other things, and because of that automation, the process can not, as in general machine tools, as can intervene at any time from the manual. Therefore, the design requirements more stringent than the general machine tools, more sophisticated manufacturing requirements. So later in the CNC machine tool design, using many new and enhanced rigidity, reduced heat distortion, improve the accuracy of such measures, make the external shape of NC machine tools, the overall layout, such as transmission and tool systems have been undergoing a very big change.

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