The CNC milling machine is developed on the basis of the manual milling machine. The processing technology of the two is basically the same, and the structure is somewhat similar, but the CNC milling machine is an automatic processing machine controlled by the program, so its structure is also very different from the manual milling machine. CNC milling machine is generally composed of CNC system, main drive system, feed servo system, cooling and lubrication system, etc.:
- 1: The spindle box includes the spindle box and the spindle drive system, which is used to clamp the tool and drive the tool to rotate. The spindle speed range and output torque have a direct impact on machining processing.
- 2: The feed servo system is composed of a feed motor and a feed actuator, and realizes the relative motion between the tool and the workpiece according to the feed speed set by the program, including linear feed motion and rotational motion.
- 3: The control system is the center of the motion control of the CNC milling machine, and the CNC machining program is executed to control the machine tool for machining processing
- 4: Auxiliary devices such as hydraulic, pneumatic, lubrication, cooling systems and chip removal, protection and other devices.
- 5: The basic parts of machine tools usually refer to bases, columns, beams, etc., which are the foundation and frame of the entire machine tool.
How does cnc milling work
According to the product design drawing requirements of the shape, size, accuracy and surface roughness of the part, the machining processing technology is formulated and the processing parameters are selected. Input the programmed machining program to the controller through manual programming or automatic programming with CAM software. After the controller processes the machining program, it sends commands to the servo device. The servo device sends control signals to the servo motor. The spindle motor rotates the tool, and the servo motors in X, Y and Z directions control the relative movement of the tool and the workpiece according to a certain trajectory, so as to realize the cutting of the workpiece.
CNC milling machine is mainly composed of bed, milling head, vertical table, horizontal saddle, lifting table, electrical control system, etc. It can complete basic milling, boring, drilling, tapping and automatic work cycles, and can process various complex cams, templates and mold parts. The bed of the CNC milling machine is fixed on the base for installation and various parts of the machine tool. The console has a color LCD display, machine operation buttons and various switches and indicators. The vertical worktable and the horizontal slide are installed on the lifting platform, and the X, Y, Z coordinate feeding is completed by the driving of the longitudinal feed servo motor, the lateral feed servo motor and the vertical lift feed servo motor. The electrical cabinet is installed behind the bed column, which houses the electrical control part.
Performance index of CNC milling machine:
- 1: The point control function can realize the processing that requires high mutual position accuracy.
- 2: The continuous contour control function can realize the interpolation function of straight line and circular arc and the processing of non-circular curve.
- 3: The tool radius compensation function can be programmed according to the dimension of the part drawing, without considering the actual radius size of the tool used, thereby reducing the complex numerical calculation during programming.
- 4: The tool length compensation function can automatically compensate the length of the tool to meet the requirements for the adjustment of the length and size of the tool during processing.
- 5: Scale and mirror processing function, the scale function can change the coordinate value of the processing program according to the specified scale to execute. Mirror processing is also known as axisymmetric processing. If the shape of a part is symmetrical about the coordinate axis, only one or two quadrants need to be programmed, and the contours of the remaining quadrants can be achieved by mirror processing.
- 6: The rotation function can execute the programmed processing program by rotating it at any angle in the processing plane.
- 7: Subprogram calling function, some parts need to repeatedly process the same contour shape at different positions, take the machining program of a contour shape as a subprogram and call it repeatedly at the required position to complete the machining of the part.
- 8: The macro program function can use a general instruction to represent a series of instructions to achieve a certain function, and can operate on variables, making the program more flexible and convenient.
Types of cnc milling machines
- 1: CNC vertical milling machine, vertical CNC milling machine, the main part is mainly composed of base, column, saddle, worktable, spindle box and other components, of which the five main parts are made of high-strength and high-quality castings and resin sand molding, the organization is stable , to ensure that the whole machine has good rigidity and precision retention. The three-axis guide rail pair adopts a combination of high-frequency quenching and plastic-coated guide rails to ensure the running accuracy of the machine tool and reduce frictional resistance and loss. The three-axis transmission system is composed of precision ball screws and servo system motors, and is equipped with automatic lubrication devices. The three axes of the machine tool are all made of stainless steel guide rail telescopic cover, which has good protection performance. The whole machine is fully closed, with larger doors and windows, and the appearance is neat and beautiful. The operation control box is placed in the right front of the machine tool, which can be rotated and is easy to operate. It can perform various milling, boring, rigid tapping and other processing, and is cost-effective. It is an ideal equipment for high-quality, high-precision and high-efficiency in the machinery manufacturing industry.
- 2: Horizontal CNC milling machine, the same as general horizontal milling machine, its spindle axis is parallel to the horizontal plane. In order to expand the processing range and expand functions, horizontal CNC milling machines usually use a CNC turntable or a universal CNC turntable to achieve 4 and 5 coordinate processing. In this way, not only the continuous revolving contour on the side of the workpiece can be machined, but also the “four-sided machining” can be realized by changing the station through the turntable in one installation.
- 3: Vertical and horizontal CNC milling machines. At present, such CNC milling machines are rare. Since the spindle direction of this type of milling machine can be changed, it can achieve both vertical processing and horizontal processing on one machine tool. , and at the same time has the functions of the above two types of machine tools, its use range is wider, the functions are more complete, the room for selecting processing objects is larger, and it brings a lot of convenience to users. Especially when the production batch is small, there are many varieties, and two methods of vertical and horizontal processing are required, the user only needs to buy one such machine tool.
