1. Overview of vertical machining center (VMC)
Vertical machining center (Vertical Machining Center, abbreviated as VMC) is a high-precision, high-efficiency CNC machine tool widely used in mechanical manufacturing, automotive, aerospace, and mold industries. Its core feature is that the spindle is perpendicular to the worktable, enabling various machining operations such as milling, drilling, boring, and tapping, making it suitable for the precision machining of complex parts.
The development of VMC can be traced back to the middle of the 20th century. With the continuous progress of CNC technology, its performance and function have been greatly improved. Modern VMC is usually equipped with advanced CNC system, high-precision servo drive system and intelligent tool management system, which can achieve high speed, high precision and high reliability processing.
2. Working principle and structure of VMC
(1) Working principle
The working principle of VMC is based on CNC technology. The machine tool's axis movement is controlled by pre-written machining program to realize accurate machining of workpiece. The specific process is as follows:
Part design and programming: Use CAD/CAM software to model parts in three dimensions and generate CNC machining programs (G codes).
Program transmission and loading: The generated program is transmitted to the CNC system of the machine tool through data lines or networks.
Workpiece clamping and tool alignment: the workpiece is fixed on the worktable, and the relative position between the tool and the workpiece is determined by the tool alignment instrument.
Automatic machining: start the machine tool, the CNC system controls the spindle rotation, worktable movement and tool feed according to the program instructions, and completes the part processing.
Quality inspection: after processing, the parts are tested with measuring equipment to ensure that the processing accuracy meets the requirements.
(2) Structural composition
The VMC consists of the following components:
Spindle system: including spindle motor, spindle bearing, tool clamping device, etc., responsible for the rotation and cutting motion of the tool.
Workbench system: including workbench, guide rail, screw rod, etc., to realize the movement of workpiece in the three directions of X, Y and Z.
Numerical control system: as the "brain" of VMC, it is responsible for processing machining programs, controlling the movement of each axis and monitoring the status of the machine tool in real time.
Knife library and automatic knife changing device (ATC): store the tool and realize the automatic knife changing function to improve the processing efficiency.
Cooling and chip removal system: the cutting temperature is reduced by coolant, and the chip is discharged in time to ensure a clean processing environment.
Lubrication system: lubricate the guide rail, screw and other moving parts to reduce wear and tear and prolong service life.
3. Application fields of VMC
VMC plays an important role in many industries due to its high precision, high efficiency and flexibility:
Automobile manufacturing: used to process engine cylinder body, cylinder head, transmission housing and other key parts to ensure the performance and reliability of the automobile power system.
Aerospace: Processing complex parts such as aircraft structural parts, engine blades and impellers to meet the requirements of high precision and high strength in the aerospace field.
Mold manufacturing: production of plastic molds, die-casting molds, stamping molds, etc., to ensure the accuracy and surface quality of molds, improve production efficiency.
Electronic industry: processing electronic component shell, heat sink, circuit board, etc., to meet the demand of miniaturization and high precision of electronic products.
Medical devices: manufacturing precision parts such as surgical instruments and implants to ensure the safety and effectiveness of medical devices.
4. Technical development trend of VMC
With the development of intelligent and automated manufacturing, VMC technology is also constantly innovating and upgrading:
High speed cutting technology: high speed spindle and rapid feed system are used to improve machining efficiency and surface quality. For example, the spindle speed of VMC1160 machining center can reach 15,000 rpm and feed speed can reach 6000mm/min.
Five-axis Interlocking Technology: By adding two additional rotation axes (such as the A-axis and C-axis), five-axis interlocking machining is achieved, enabling the processing of more complex curved parts, such as impellers and blades in the aerospace industry. VMC850 The five-axis interlocking machining center uses a 3+2 five-axis structure, offering high cost-effectiveness and is suitable for the machining of high-precision complex curved molds.
Intelligent and automation: equipped with intelligent numerical control system, sensors and industrial Internet of Things technology, real-time monitoring of the processing process, fault diagnosis and predictive maintenance.
Green manufacturing: energy saving motors, environmental cutting fluid and efficient chip removal system are used to reduce energy consumption and environmental pollution.
5. Operation and programming of VMC
(1) Operation process
Part clamping: according to the shape and size of the part, select the appropriate fixture to fix the workpiece on the workbench, and ensure that the clamping is firm.
Tool selection and installation: Select appropriate tools according to the requirements of machining process, and install them on the tool bank or spindle.
Tool alignment: Use the tool alignment instrument or manually determine the relative position of the tool and the workpiece, and input it into the CNC system.
Program input and debugging: the programmed processing program is input into the CNC system, and the simulated processing is carried out to check the correctness of the program.
Automatic machining: start the machine tool for automatic machining, operators need to pay close attention to the machining process, timely deal with abnormal conditions.
Part inspection and quality control: after processing, the parts are tested with measuring tools, such as three-coordinate measuring instrument, roughness meter, etc., to ensure that the quality of parts meets the requirements.
(2) Programming method
Manual programming: Suitable for simple parts processing, by directly inputting G code and M code to control machine tool movement.
Automatic programming: use CAD/CAM software for part design and programming, generate machining programs. Commonly used software includes MasterCAM,UG,PowerMill, etc.
Five-axis programming: For five-axis linkage machining, special five-axis programming software, such as HyperMill, Vericut, etc., is needed to achieve accurate machining of complex surfaces.
6. Maintenance and maintenance of VMC
Regular maintenance and maintenance is the key to ensure the long-term stable operation and processing accuracy of VMC:
maintenance overhaul:
Clean the appearance of the machine tool and remove chips and oil.
Check the oil and coolant level, and add them in time.
Check whether the pressure of the pneumatic and hydraulic systems is normal.
Check the lubrication of moving parts such as spindle and guide rail.
periodic maintenance:
Check the tool pull bolt is not loose and the tool bank arm movement is smooth every week.
Check the lubrication of the X, Y and Z axis guides every month, and clean the limit switch and bump.
Check the running state of servo motor and spindle motor every six months, and replace the lubricating oil.
A comprehensive precision calibration and mechanical level adjustment are carried out every year.
debugging:
When the machine tool is faulty, first check the alarm information of the CNC system and troubleshoot according to the prompt.
Common faults include tool damage, spindle noise, poor guide rail lubrication, etc., which need to be replaced or repaired in time.