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What is vmc machine?
- As discussed in the article on CNC machines, machines operated by computers are called Computerized Numeric Control (CNC) machines. CNC machines are available in a wide range for various applications, with CNC milling machines being particularly well-known.
- Milling is a material removal process that involves rotating a tool against a workpiece. The addition of computerized control to the milling process has led to the development of various machining centers or milling centers.
- Machining centers such as Vertical, Horizontal, and Universal are widely used in various industries today. Among these, this article focuses on the Vertical Machining Center, commonly known as the VMC machine.
Construction of VMC Machine
- In the article on types of milling machines, we explored four different types based on their construction. Among these, the Column and Knee type milling machines are particularly well-known.
- In the above type of milling machine, the work table is mounted on the knee, which can move in different directions. The knee moves up and down on the column, which supports the entire weight of the machine and transfers it to the base.
- Among the Column and Knee type milling machines, VMC machines are particularly famous. In the construction of a VMC machine, the milling spindle is mounted vertically, perpendicular to the knee and parallel to the column, to remove material from the workpiece. This orientation is why it is called a 'Vertical Milling' or 'Vertical Machining Center'.
- A general VMC machine can move along three different axes, namely X, Y, and Z. This movement is facilitated by servo motors, linear motion (LM) guideways, and ball screws. Due to the axis movement, the spindle can move front-back, left-right, and up-down, synchronizing with the rotation of the tool to remove material efficiently.
What is the working principle of VMC Machine?
- In the early days, milling machines were operated manually, with the axes moved by hand wheels. However, with the introduction of computers in manufacturing, VMC machines are now automatically operated by controllers.
- For working of VMC machine automatically, we have to provide G code M code to machine and this code generate by Various CAD CAM software. Machine controllers understand that code and give command to movement of axis motor to move axis to remove materials.
- This motion is synchronized with the spindle rotation, meaning the spindle rotates at a specific RPM while moving in three different directions around the workpiece according to the G-code.
- Also many components are given in VMC to better performance of VMC machine.
What are the main components of VMC machine?
In the manufacturing of a VMC machine, numerous components are required, encompassing both mechanical and electrical elements. These components are listed below:
Base
- VMC machines are constructed on a heavy casting base to ensure superior strength and rigidity. Initially, the base is cast using a casting process. Subsequently, machining operations are performed on the base to mount the column, knee, and other components of the VMC machine.
- Various axes are mounted on this base to facilitate movement. Additionally, coolant and chip removal systems are integrated into the base for efficient operation.
Column
- The column of a VMC machine is the vertical component where the spindle is mounted with the assistance of the Z-axis, enabling vertical motion up and down along the column. Within the column, provisions are made for coolant passage and wiring for the motor and spindle, ensuring efficient operation and maintenance.
Axis
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The axis of a VMC machine relies on several key components for movement, including:
- Ball screw
- Linear motion (LM) guide ways
- LM block
- Precision nut
- Servo motor
- Coupling
- Motor bracket
- BK-BF components
- These components work together to facilitate precise and controlled movement within the VMC machine.
- In a VMC machine, T-slotted work tables are utilized for mounting workpieces using fixtures or clamping tools. These work tables are mounted on the saddle and knee, allowing for front-back and left-right movement, facilitating versatile positioning and machining of workpieces.
Spindle
- The spindle serves as the cutting component of a VMC machine, rotating via a motor. It enables the cutting tool to remove material from the workpiece during machining operations.
Electrical assembly
- For power supply and regulation to each component as per requirement, a separate electrical assembly panel is utilized. This panel incorporates various components such as drives, VFDs (Variable Frequency Drives), controllers, switches, transformers, SMPS (Switched Mode Power Supply), relays, wiring, cables, and more. These components work together to ensure reliable and efficient operation of the VMC machine.
Sheet metal Guard
- To enhance protection and safety measures during potential accidents, VMC machines are equipped with a sheet metal guard featuring a unique design. This guard serves as a protective enclosure for components such as touch screens, oil chambers, switches, and other essential elements.
- The controller acts as the brain of any CNC machine, orchestrating commands to the axis motors, spindle, coolant, and oil chamber to function according to requirements. Serving as a specialized type of computer, similar to how computers understand binary language, the controller of a CNC machine comprehends G-code and M-code. Through the interpretation of this code, the controller synchronously maneuvers the axis and spindle to efficiently remove material.
What are the advantages of VMC machine?
Higher degree of accuracy
- The controller acts as the brain of any CNC machine, orchestrating commands to the axis motors, spindle, coolant, and oil chamber to function according to requirements. Serving as a specialized type of computer, similar to how computers understand binary language, the controller of a CNC machine comprehends G-code and M-code. Through the interpretation of this code, the controller synchronously maneuvers the axis and spindle to efficiently remove material.
Time Reduction
- The main advantages of VMC machines over manual machines are their ability to complete machining tasks more quickly due to automation, precise cutting tools, and integrated cooling systems. Additionally, the inclusion of CAD/CAM in CNC machines streamlines processes by optimizing programs, further enhancing efficiency and accuracy.
Complex parts manufacturing
- Parts such as dies, patterns, automobile engines, aerospace components, and defense components require high precision, tight tolerances, and often feature small sizes with critical geometries. These characteristics make manual manufacturing processes impractical.
- VMC machines offer a feasible solution over other methods due to their ability to achieve precision, handle complex geometries, and maintain tight tolerances in manufacturing these critical components.
Greater surface finishing
- The surface finishing achieved with VMC machines is notably high, attributed to the availability of complex finishing tools, precise axis motion, temperature-reducing systems, thorough cooling systems, and the ability to perform post-processing operations after machining.
Reduce man power requirement
- VMC machines can produce critical parts with only 2 to 3 personnel, whereas manual processes require more manpower. Additionally, in VMC machine operations, workers primarily oversee machine operation, eliminating the need for physically demanding manual labor associated with traditional machining processes.
What are the disadvantages of VMC Machine?
High intial cost
- A major drawback of CNC machines is their high cost, primarily due to their heavy structure and precision requirements. Additionally, the cost of tooling, jigs and fixtures, electrical power consumption, and cutting oil is higher compared to conventional machines. As a result, the machining cost of parts produced using CNC machines tends to be higher.
Risk of accident
- The high-speed movements of VMC machines pose significant risks in the event of accidents. Errors such as incorrect part referencing, programming errors, operator mistakes, or machine miscommunication can result in dangerous accidents and extensive damage to the machine.
Service and maintenence
- The costs and time required for repairing damaged parts in VMC machines, such as the spindle, axis motor, LM or ball screw, are considerable. Repair processes can be time-consuming, sometimes requiring 15 to 30 days for maintenance. A major drawback of VMC machines is their tendency to create dependency on machine manufacturers for service.
Machine operating
- Operating a VMC machine is a complex process that requires regular cleaning, proper usage, and adherence to error-free procedures to enhance machine life and prevent accidents.
Trained person required
- Operating a VMC machine is a complex task that involves proficiency in CAD, CAM, CNC programming, and machine operation. Trained individuals with knowledge of design, VMC programming, and machine operation are required to effectively operate these machines.
What are the application of VMC machine?
VMC machines offer numerous advantages, making them applicable across a wide range of industries such as aerospace, automobile, manufacturing, defense, marine, and others.
Aerospace industry
- Aerospace manufacturers use VMC machines to manufacture, assemble, and maintain essential aircraft and space shuttle components. A single error in any component can lead to dangerous results because it is directly connected to human life.
Automobile industry
- With technological advancements in the CNC field, most components are now manufactured using various CNC machines. From the outer structure to the fabrication of vehicles, processes such as CNC laser cutting and bending are employed.
Manufacturing industry
- In earlier days, manual and conventional machines were used in the manufacturing industry. These machines were affected by factors such as being time-consuming, costly, less accurate, and capable of only simple machining.
- However, with the integration of advanced technology, particularly computerized numeric control (CNC) machinery, many of these problems have been solved. Today's manufacturing industry is integral to Industry 4.0.
Marine industry
- Marine equipment is constantly exposed to water, making it highly susceptible to corrosion. Therefore, it is necessary to use corrosion-resistant materials due to the constant exposure to humidity or direct contact with water. This includes various marine-grade metals such as steel, copper, and brass.
- For this reason, CNC machining is a versatile method that produces durable and corrosion-resistant components for marine equipment, ranging from small boats to large shipping vessels.
Defence industry
- In the last 10 years, countries have been focusing on their defense sectors and developing more defense equipment for security purposes. As the industry upgrades, there is a need for high-end systems capable of precisely generating accurate products.
- Components for defense are manufactured using CNC technology, which integrates with CAD, CAM, and ERP systems, ensuring seamless user interaction. Companies like DMG Mori, Haas, Mazak, and Makino specialize in manufacturing CNC machines that precisely produce defense components.
What is the VMC programming?
- A VMC (Vertical Machining Center) machine is controlled by an industrial controller manufactured by companies like Siemens, Fanuc, Mitsubishi, etc. These controllers understand specific G-codes and M-codes and interpret them to give commands to various components of the VMC machine.
- To write this code according to your design, there are many software options available such as NX, MasterCAM, SolidWorks, etc. Alternatively, you can write the program manually if you have knowledge of each command.
For your guidance on how these commands look, here is an example program:
; Example CNC program to mill a rectangular pocket
; Units in millimeters
G21 ; Set units to millimeters
G17 ; Select XY plane
G90 ; Absolute positioning
; Start spindle and move to start position
M6 T1 ; Tool change to tool 1
M3 S1200 ; Start spindle at 1200 RPM
G0 Z5.0 ; Raise to clearance height
G0 X0 Y0 ; Move to start position
; Start cutting
G1 Z-1.0 F100 ; Move down to cutting depth
G1 X50.0 F200 ; Move to X50
G1 Y30.0 ; Move to Y30
G1 X0 ; Move back to X0
G1 Y0 ; Move back to Y0
; Finish up
G0 Z5.0 ; Raise to clearance height
M5 ; Stop spindle
G0 X0 Y0 ; Return to home position
M30 ; End of program
Standard G-code and M-code list: click here
Faqs
What is the history of computer numerical control?
The credit for inventing the earliest version of an NC (numerical control) machine goes to John T. Parsons and Frank L. Stulen. The drive for automation, influenced by the Industrial Revolution in the early 1700s in Europe and neighboring countries, led to significant advancements in precision and accuracy. During this time, a team at MIT developed a punch card system for moving machine axes. However, Parsons and Stulen are credited with inventing the earliest versions of punch cards while working on the production of helicopter blades. In 1952, Arma Corporation successfully built a numerically operated lathe machine. With the advent of the computer revolution, research in automatic machines increased, leading to the introduction of CNC (computer numerical control) controllers in the 1970s, which operated using specific codes. Further developments included the integration of CAD (computer-aided design) and CAM (computer-aided manufacturing) along with CNC language, with G-code becoming a widely used language in CNC machines to this day.
What is the work of a VMC machine?
VMC Machine works on principle of milling machine to remove material from metal and non metals. Operation of drilling, taping, miling, face, side, contour, O.D., I.D., Slotting, Grooving, Interpolation milling is done on VMC machine.
What is VMC full form?
The full form of VMC is "Vertical Machining Center" or "Vertical Milling Center".
Which company is best for CNC machines?
| Comapany name | Headquater | official website |
|---|---|---|
| DMG Mori | Bielefeld, Germany | dmgmori.com |
| Hass automation | Oxnard, California | hasscnc.com |
| Mazak | Aichi Prefecture, Japan | mazak.com |
| Makino | Tokyo, Japan | makino.com |
| Philips | Mumbai, India | phillipscorp.com |
Thank you.