Types Of Nc Machine Tools. The Difference Between Various Machine Tools...

[Aquilino Hession]

basic composition

the basic composition of NC machine tool includes processing program carrier, NC device, servo drive device, machine tool main body and other auxiliary devices. The basic working principle of each component is briefly described below
processing program carrier

when the NC machine tool is working, workers do not need to operate the machine tool directly. To control the NC machine tool, it is necessary to

prepare the processing program for the high-speed NC machine tool

. The part processing program includes the relative motion trajectory of the tool and workpiece on the machine tool, process parameters (feed rate, spindle speed, etc.) and auxiliary motion. The part processing program is stored on a program carrier with a certain format and code, such as perforated paper tape, cassette tape, floppy disk, etc., and the program information is input to the CNC unit through the input device of the NC machine tool
NC device

NC device is the core of NC machine tool. Modern numerical control devices adopt the form of CNC (computer numerical control). This CNC device generally uses multiple microprocessors to realize the numerical control function in the form of programmed software, so it is also called software NC. CNC system is a position control system. It interpolates the ideal motion trajectory according to the input data, and then outputs it to the executive part to process the required parts. Therefore, the numerical control device is mainly composed of three basic parts: input, processing and output. All these works are reasonably organized by the computer system program to make the whole system work in coordination
1) input device: input numerical control instructions to the numerical control device. There are different input devices according to different program carriers. It mainly includes keyboard input, disk input, direct communication input of CAD /CAM system and DNC (direct numerical control) input connected to the superior computer. At present, many systems still retain the paper tape input form of photoelectric reader
(1) paper tape input method. The part program can be read into the paper tape photoelectric reader to directly control the movement of the machine tool, or the paper tape content can be read into the memory, and the part program stored in the memory can be used to control the movement of the machine tool
(2) MDI manual data input method. The operator can use the keyboard on the operation panel to input the instructions of the processing program, which is suitable for relatively short programs
in the edit state of the control device (Edit), input the processing program with software and store it in the memory of the control device. This input method can reuse the program. This method is generally used in manual programming
on the NC device with session programming function, you can select different menus according to the questions prompted on the display, and enter the relevant dimension numbers by means of man-machine dialogue, so as to automatically generate the machining program
(3) DNC direct NC input mode is adopted. The part program is saved in the superior computer, and the CNC system receives the subsequent program segments from the computer while processing. DNC mode is mostly used for complex workpieces designed by CAD /CAM software and directly generating part programs
2) information processing: the input device transmits the processing information to the CNC unit and compiles it into information that can be recognized by the computer

different types of CNC machine tools (13 pieces)

information, which is gradually stored and processed by the information processing part according to the provisions of the control program, and then sends position and speed commands to the servo system and the main motion control part through the output unit. The input data of CNC system includes: contour information of parts (starting point, end point, straight line, arc, etc.), processing speed and other auxiliary processing information (such as tool change, speed change, coolant switch, etc.). The purpose of data processing is to complete the preparation before interpolation operation. The data processing program also includes tool radius compensation, speed calculation and auxiliary function processing

3) output device: the output device is connected with the servo mechanism. The output device receives the output pulse of the arithmetic unit according to the command of the controller and sends it to the servo control system of each coordinate. After power amplification, it drives the servo system to control the machine tool to move according to the specified requirements
servo and measurement feedback system

servo system is an important part of NC machine tool, which is used to realize feed servo control and spindle servo control of NC machine tool. The function of the servo system is to convert the received command information from the NC device into the linear displacement or angular displacement of the machine tool's executive parts after power amplification and shaping. As the servo system is the last link of the NC machine tool, its performance will directly affect the accuracy, speed and other technical indicators of the NC machine tool. Therefore, the servo drive device of the NC machine tool is required to have good rapid response performance, accurately and sensitively track the digital command signal sent by the NC device, faithfully execute the commands from the NC device, and improve the dynamic following characteristics and static tracking accuracy of the system
the servo system consists of two parts: driving device and actuator. The driving device is composed of spindle driving unit, feed driving unit, spindle servo motor and feed servo motor. Stepping motor, DC servo motor and AC servo motor are common driving devices
the measuring element detects the actual displacement value of each coordinate axis of the NC machine tool and inputs it into the NC device of the machine tool through the feedback system. The NC device compares the actual displacement value fed back with the command value and outputs the displacement command required to reach the set value to the servo system
machine tool main body

machine tool host is the main body of NC machine tool. It includes machine bed, base, column, cross beam, sliding seat, worktable, spindle box, feeding mechanism, tool holder, automatic tool changing device and other mechanical parts. It is the mechanical part that automatically completes all kinds of cutting on the NC machine tool. Compared with traditional machine tools, the main body of CNC machine tools has the following structural characteristics:

1) a new machine tool structure with high stiffness, high seismic resistance and small thermal deformation is adopted. Generally, the stiffness and seismic resistance of the machine tool host are improved by improving the static stiffness of the structural system, increasing damping, adjusting the quality and natural frequency of structural parts, so that the machine tool body can meet the needs of continuous and automatic cutting of NC machine tools. The influence of thermal deformation on the machine host can be reduced by improving the structural layout of the machine tool, reducing heating, controlling temperature rise and adopting thermal displacement compensation
2) high performance spindle servo drive and feed servo drive devices are widely used to shorten the transmission chain of NC machine tools and simplify the structure of mechanical transmission system of machine tools
3) transmission devices and moving parts with high transmission efficiency, high precision and no gap are adopted, such as ball screw nut pair, plastic sliding guide rail, linear rolling guide rail, hydrostatic guide rail, etc
auxiliary device of NC machine tool

auxiliary device is necessary to give full play to the function of NC machine tool. Common auxiliary devices include: pneumatic, hydraulic device, chip removal device, cooling and lubrication device, rotary worktable and NC dividing head, protection, lighting and other auxiliary devices. Vertical machining center, horizontal machining center, turn milling compound machining center, horizontal boring and milling machining center, floor type boring and milling machining center, 5-axis linkage vertical machining center, 5-axis and 4-axis linkage horizontal boring and milling machining center, double spindle multi spindle machining center, gantry machining center, NC grinder, NC grinding center, NC turning center, NC vertical turning center, plane, outer circle, pin hole and other grinding centers, Crankshaft grinding center, CNC medium temperature furnace
main differences:

1. Spindle

2. Design of bed and column

3. System stability

4. Lubrication and hydraulic system

5. Cutting system and air pressure system

6. Tool magazine and manipulator

7. Circuit system

CNC machine tools are no different from ordinary machine tools. What ordinary machine tools have, CNC machine tools have. The difference is that the manufacturing accuracy and people almost change the platform are much better than ordinary machine tools
if you ask about CNC machining center, I can give you several names. If you want to ask about the differences between them, you'd better buy a Book of CNC machining center and see their classification. If you want to tell all their differences, you can produce a milling operation very thick book
Name: vertical machining center, horizontal machining center, turn milling compound machining center, horizontal boring and milling machining center, floor type boring and milling machining center, 5-axis linkage vertical machining center, 5-axis 4-linkage horizontal boring and milling machining