CNC Machining System: Working Principle Advantage & Disadvantage

Working principle of CNC Machining system

In this article, we will learn about CNC Machining System: Working Principle Advantage & Disadvantage. Computer numerical controlled (CNC) machines are machines that control all the movements of NC machines using a computer and are used to produce the product.
In CNC machines, the input data required to run them is delivered directly in the form of a part program via an input device.

Components of the CNC Machining system

1. Central Processing Unit (CPU)
2. Servo control unit
3. Operator control panel
4. Machine control panel
5. Other peripheral devices
6. Programmable Logic Controller (PLC)

1. Central Processing Unit (CPU)

The CPU memory program is decoded and transferred to a specific axis and spindle rotation. When this value does not match the axis of spindle rotation movements the machine’s lead screw pitch error, backlash error, tool wear Guit Got error is corrected and compensated by the CPU.

2. Servo – Control Unit

The position and velocity control signals generated by the CPU are decoded and input into the servo control unit. The servo control system transfers these input signals to DC or AC servo motor drives and causes machine movements.

Furthermore, the servo control system receives the feedback signal from the feedback devices and causes the actual movements of the right axis. Velocity became feedback
is received from the tech generator.

3. Operator control panel

This control panel acts as a two-way communication system between the user and the CNC system, CNC machine tools.

It consists of 1. Video Display Unit (VDU) and 2. Keyboard

4. Video Display Unit (VDU)

It displays different types of CNC system parameters. Also displays program entry data and the actual position value, current feed, and spindle speed when the machine is running.

5. Keyboard

This keyboard is used to edit the program, enter tool data and machine parameters, select operation modes, and execute the program.

6. Machine Control Panel (MPC)

It is the interface unit between the operator and the CNC system. The CNC controls the axis and spindle movements while exciting the program. At the same time, the machine is ready for the following tasks.

• Fixing the reference point
• Loading the system memory with the required part program
• Loading and checking tool offsets etc.
  

7. Programmable Logic Controller (PLC)

The PLC control system is used to sequentially automate the operations of all ON / OFF switches on the CNC machine. For example operations like spindle ON / OFF, coolant ON / OFF, ATC ON / OFF are controlled by PLC.

Advantages of CNC Machines

• Able to do mass production.
• Manufacturing Lead Time is reduced.
• Increases product accuracy.
• No errors caused by the Machine Operator.
• Modification and editing work in programs can be done easily through the control panel in the machine.
• A single machine operator can oversee more than one CNC machine.
• Suitable for batch production.
• Tool life increases.
• No special jigs and fixtures required.
• Flexible manufacturing is able to adapt to changes in product design.
• Inspection timeless
• Scrap size is reduced.

Disadvantages of CNC system

• • Initial Investment More
  • Maintenance cost is high
  • An experienced person is required to perform the service
  • The service cost is high.

Application of CNC Machines

• Turning
• Milling
• Drilling
• Grinding
• Boring and Tapping
• Sawing
• Laser cutting machine
• EDM machining etc. ,

Other applications

• Pressing Tool
• Welding machine
• Pipe bending
• Flame cutting
• Plasma is cutting
• Laser beam processes
• Inspection machines
• Cloth cutting
• automated riveting
• Wire – wrap machines
• Material handling process