CNC Machine: Types, Parts, Advantages, Disadvantages, Applications, and Specifications (With PDF)

As we know machines like lathe, Milling, and Drilling operations are performed manually and there is more involvement of humans to perform and time taking is high average precision and accuracy. So to overcome this problem, the machine manufactured is CNC which is known as Computer Numerically controlled. let’s understand in detail also at the end of the article I will give a PDF downloadable link also.

There is a written program for the CNC machine, before going to operate the CNC machine. First, we insert or feed the operation program on the CNC machine and set the workpiece on it, and start the machining process.

One more thing I would like to share with you is that lathe machine operation or any manual machine operation is carried, there the heat generated between tool and workpiece. To avoid this we have to put water or any other coolant to reduce heat.

But in the case of the CNC machine where water parts are automatically set, there is no need to provide them manually.

What is a CNC Machine?

A CNC machine can be defined as a machine that is controlled by a computer and the operation is performed by feeding the program on it.

CNC machine operates on only two subjects which are CAD and CAM.

CAD stands for Computer-aided design. This subject helps you to learn about the design of a machine and machine tools.

CAM stands for Computer-aided manufacturing. This subject is also similar to CAD but it deals with manufacturing whereas CAD deals with design.

Parts of CNC Machine:

A CNC machine consists of the following parts:

  • Bed
  • Headstock
  • Tailstock
  • Tailstock quill
  • Footswitch or pedal
  • Chuck
  • Control panel
  • Tool turret

Let’s go into detail.

Bed:

The bed is a kind of hardened part of a machine because The tool turret travels over the CNC lathe bed, kind of machining can’t affect them.

Headstock:

The headstock is the main part of the machine, here the workpiece is fixed to perform an operation also Headstock of a CNC lathe machine has the main motor which drives the main spindle.

Tailstock:

The tailstock is for providing extra grip to the workpiece. When operations like knurling, and threading has performed these parts are used to hold the workpiece.

Tailstock quill:

This is kind of setting the workpiece between the centers.

Footswitch or pedal:

Through these pedals, CNC machinists open and close the chuck to grip the component, the same way the tailstock quill is taken to a forward position or reversed.

Chuck:

Chuck is mounted on the main spindle. Here we fixed the workpiece.

Control panel:

The control panel is another main part of the CNC machine in which we use to set or feed the program for the operation we perform on the workpiece.

This is also called the brain of a CNC machine.

Tool turret:

The tool is mounted on the tool turret which is used for component machining.

Tool turrets vary in shape and the number of tools that can be mounted on them.

These are the Parts of a CNC machine, now I will talk about the CNC system.

Elements of the CNC Machine system:

A CNC machining system consists of the following elements:

  • Program
  • Tape Reader
  • Mini-computer
  • Servo system
  • CNC machine tool

Program:

This is entered into the computer through a keyboard. These are the codes used to control the machine.

The various CNC codes are N Code, G Code, XYZ Code, F code, etc.

Below is the table where I write all the common codes used in CNC.

Tape Reader:

This is used as a storage device where we can store the program for a particular machining operation.

Any modification of a program can easily be done by editing the existing program as per your requirement.

Mini-computer:

It is also called the machine control unit. It is to read interpret and converts perceived input, that is part program into the desired movement and controls the following functions:

  • To start and stop the machine spindle.
  • Vary the spindle speed accordingly and also it can control the direction of rotation of the spindle.
  • To start and stop the coolant supply.
  • To change the required tools as per requirements.
  • To change the workpiece.
  • To control the feed rate.

Also, the mini-computer is equipped with diagnostic software which can detect any problem and restore the machine accordingly.

Servo system:

The function of the servo system is to receive the control signal from the feedback devices and the set output accordingly (To shaft, tools, and other components of the CNC machine)

Servo system mainly consists of:

  1. Servo Motors
  2. Feedback devices
  3. Ball screws

CNC Machine:

This is the actual machine where the finished product is made. I already mentioned the parts of the CNC machine above this heading.

This is the housing of the headstock, tailstock, foot switch, chuck, and tool turret.

block diagram of cnc machine
Block diagram of CNC Machine

How does a CNC Machine Work?

The details explained above are all about the CNC machine.

The CNC machine works based on CAD and CAM programs and computer control.

CAD (Computer-Aided Design) is drawing software.

Also, CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and create a database for manufacturing.

Whereas, CAM (Computer-Aided Manufacturing) has two codes G-code and M-codes on which all the programs are written and fed into the machine to perform the various operations. (i.e. turning, grooving operation in a lathe)

Here is the example of steps:

  • The first step is, to write and Insert the part program which is (G and M code) into the Machine Control Unit of the CNC machine.
  • Now all the data process takes place and according to the program it prepares commands and sends them to the driving system.
  • The drive system controls the motion and velocity of the machine tool.
  • The feedback system records the position and velocity measurement of the machine tool and sends a feedback signal to the MCU.
  • In MCU, the feedback signals are compared with the reference signals and if there are errors, it corrects it and sends new signals to the machine tool for the right operation to happen.
  • The display unit is used to see all the commands, programs, and other important data.

Here is a Working Video of a CNC Machine:

Video Source: LA Machines

Types of CNC Machine:

CNC machines are can be classified into the following types:

  • CNC laser cutting machine
  • CNC Lathe Machine
  • CNC Milling Machine
  • CNC router Machine
  • CNC Plasma Cutting Machine
  • 5- axis machine
  • 3-D Printer
  • Pick and Place Machine

CNC laser cutting machine:

As the name itself indicates “Laser cutting” means the cutting operation is carried by a laser and the operation code is fed into the machine and runs automatically, it is called CNC laser cutting machine.

This machine is used for sheet cutting.

It provides a better surface finish.

Even a complicated design can be made in this you just have to feed the program according to it.

The machine cost is very high.

The major problem faced is when machine parts got damaged it takes time to fix because of unavailability in the market.

CNC Lathe Machine:

Before moving further on the CNC Lathe machine I wanna tell you that I have covered Lathe Machine in detail, I have discussed every possible point on the lathe machine you should check it too.

Now moving to CNC Lathe machine.

CNC stands for Computerized numerically controlled.

This is widely used as a lathe in the present time because of its fast and accurate working. It is one of the most advanced types.

It uses computer programs to control the machine tool. Once the program is fed into the computer as per the program it starts operation with very high speed and accuracy.

Even do preplanned programmed machine is there in which once code is set for the various operations it can starts operation without changing code the next time.

A semi-skilled worker can easily operate this after the initial setup is done.

These types of lathes are also used for mass production like capstan and turret but there is no programmed fed system.

The components manufactured by these lathes are very accurate in dimensional tolerances.

CNC Milling Machine:

I also have written an article on the Convectional Milling machine you may check that too.

As we know Milling Machine is a process of metal-removing by feeding the workpiece passes through the rotating multipoint cutter.

This machine is used to make gears like Spur gears, and also drill the workpiece bore, and produce slots.

The same work is performed in CNC Milling by inserting the part program into the system.

A semi-skilled worker can easily operate this after the initial setup is done.

These types of machines are also used for mass production like capstan and turret but there is no programmed fed system.

The components manufactured by this machine are very accurate in dimensional tolerances.

CNC Router Machine:

It works similarly to other CNC machines as lathe or Milling do.

The main difference is, that it does all the carpenter work manually such as door carvings, interior and exterior decorations, wood panels, signboards, wooden frames, moldings, musical instruments, furniture, and so on.

As per the sketch, you can design if possible you can make it into the system then execute on this machine.

It provides a better surface finish.

This will be a very good machine in terms of the design of the door and more.

CNC Plasma Cutting Machine:

The Plasma cutting machine is defined as It is a process that cuts through electrically conductive materials using an accelerated jet of hot plasma.

Whereas CNC Plasma cutting machine is defined as the cutting operation done by a computer numerically controlled system.

We studied CNC laser cutting the main difference between them is, that one operation performs by laser which is very costly and whereas the other one is hot plasma which is less costly and these are portable.

As the industry grows, new technology is invented these are one of them. Provide a better surface finish.

5- axis machine:

It is a machine in which there is a total of 5 axes.

Initially, it was 3 axis (X, Y, and Z) the cutting operation of any instrument was done in the 3 directions but 2 additional axes were added (A, B) which means there is a total of 5 axes, and work is cut are done in the 5 direction.

5 The Axis machine is used for making sculptures.

3-D Printer:

3D Printer is a CNC machine in which the metals are printed layer by layer. The 3D printer works for the printing of buildings and complexes.

The design and drawing are made by the CAD and CAM process and then 3D Printer works for visualizing that design.

Pick and Place Machine:

This is another great type of machine. It is used in the industry. Let’s understand by a simple example.

The company Amazon has a warehouse where it used to keep a large number of items. If the items are adjusted manually it takes a great time to avoid this machine introduces to pick and place the items.

a wood CNC machine

Advantages of CNC Machine:

Following are the advantages of having a CNC machine:

  1. The CNC Machine provides a workpiece with better precision and accuracy.
  2. Fewer workers are required which helps to save labor costs.
  3. A highly skilled operator is not required. Even a trained worker can operate these CNC machines.
  4. CNC machines can produce complex designs with high accuracy in the minimum possible time.
  5. CNC machine has an online editing program, which means any changes and mistakes in cutting conditions or in dimensions can easily be edited and modified by the part data stored in the computer without sending the tape for re-processing.
  6. The conversion of the unit can easily be done by this machine (SI to British or from British to SI).
  7. It can diagnose its own fault easily, there is special software that enables easy troubleshooting if the CNC system fails to operate and also has the capability to assist in maintaining and repairing the system automatically.
  8. It also helps with safety reasons.
  9. Low Maintenace required
  10. Reduce setup change over time.
  11. The CNC Machine has Higher Production and capability.
  12. It can run for 24 hours a day.
  13. Reliable.

Disadvantages of CNC Machine:

Here are some disadvantages of CNC machine:

  1. The installation cost is high.
  2. Even the parts of the CNC machine are high.
  3. When any failure occurs in the machine a highly skilled professional requires to solve the issue.
  4. Computer knowledge is required.
  5. Program knowledge is required

Applications of CNC Machine:

These are some applications of CNC machines:

  1. The main application of the CNC machine is to remove metal at a faster rate as compared to a traditional machine-like lathe, or milling machine.
  2. This is also used in fabrication industries.
  3. This machine is used for the automatic removal of metal from the workpiece wherein another machine like a lathe, Milling the metal removal is done manually.

Specifications of a CNC Machine:

Specification of a CNC machine can be categorized into the following points:

Machine specifications:

  • Centers height.
  • Distance between centers.
  • Swing diameter over the bed.
  • Swing diameter over the cross slide.
  • Transverse movement of the cross slide.

Headstock specifications:

  • Hole in the headstock spindle.
  • Spindle end-use taper.

Tailstock specifications:

  • Spindle diameter.
  • Spindle end taper.
  • Sleeve travel.

Feed rate:

  • Rapid transverse.
  • Programmable feed rate.

Main Spindle specifications:

  • Speed range.
  • Output power.

Let Me Show You the Common Codes Used in CNC Programming:

CODEEXPLANATION OF CODE
NSequence Number.
GRapid Traverse.
X, Y, ZFor tool motion about X, Y, and Z direction (Linear Motion).
SSpindle Speed (Unit as per your setting).
FFeed Rate.
TTool Number (i.e. Tool number 1 for facing or turning).
MMiscellaneous Functions.
EOBEnd of Block (End of the program).
A, B, CFor angular direction in X, Y, and Z direction.

Difference between CNC and NC Machine:

First, let me tell you about NC Machine, NC stands for numerical control, this is also an automated machine but it can understand only binary, numeric, or alphanumeric programs.

An NC machine has

  1. Software
  2. MCU (Machine Control Unit)
  3. Machine Tools

It doesn’t have a servo mechanism there for it has no feedback system also it has no computer.

The program is typically stored in a tape with the help of a special inserting device, the modification or changes in the program is a tough job in the case of an NC machine.

Now get a small idea by seeing these differences between NC and CNC.

NC MACHINECNC MACHINE
NC stands for the Numeric control machine.CNC stands for Computer Numerically Control Machine.
This is not software driven.This is a software-driven machine.
It can not import CAD files.It can import CAD files and convert them into part programming.
Operation parameters cannot be changed.Operation parameters can be changed.
It stores in Punch cards Memory.Directly stores in computer memory.
The machine cannot run continuously.This machine can run for 24 hours continuously.
Less flexibility or Computational ability.CNC machines have High.
Takes more time for executing the program.This machine takes less time compared to the NC machine.
High-skill operator requires to operate NC machines.The semi-skilled operators can perform the operation on a CNC machine.
Less maintenance.High maintenance.
The maintenance cost is less.The maintenance cost is more.
Machining cost is less.Machining cost is more.
Less Accuracy as compared to CNC Machine.Great accuracy.
Codes are Numeric, Symbols, and letters only.Here the codes are G and M codes.
A single person can not perform several operations on different NC Machines.A single person can perform several operations on a different CNC machine.
There is no feedback system.Feedback systems are there.

Summary:

What is a CNC Machine?

CNC machine can be defined as the machine which is control by computer and the operation is performed by feeding the program on it.

What Does CNC Mean?

CNC stands for Computer Numerical Control that means this machine tool is controlled by the software of the computer. The programs are loaded in a computer through a keyboard or tape and stored in the memory, which can be called whenever we need it.

What are the different types of CNC machines?

CNC machines are can be classified into the following types:
CNC laser cutting machine
CNC Lathe Machine
CNC Milling Machine
CNC router Machine
CNC Plasma Cutting Machine
5- axis machine
3-D Printer
Pick and Place Machine

What is the full form of CNC?

CNC stands for Computer Numerical Control.

What are the Different Parts of CNC machines?
A CNC Machine consists of following parts:

Bed
Headstock
Tailstock
Tailstock quill
Footswitch or pedal
Chuck
Control panel
Tool turret

What are the Different Parts of the CNC system?
A CNC machine system consists of the following elements:

Program
Tape Reader
Mini-computer
Servo system
CNC machine tool

Conclusion:

As we already have seen that this type of system is software-based, the machine tools are controlled by means of software. This system simplifies the usage of conventional machining processes.

Although nowadays you probably have seen at least one CNC machine in any industry it lowers productivity as well. So it’s better to be a knowledgeable person in the space of the CNC machine because this is the future of Manufacturing Technology.

So these are all about CNC machines, now I want to hear from you, ask me anything related to this topic in the comment section, also you can participate in our discussion board here is the link to that.

Also, we have lots of articles on the Mechanical Engineering topic, visit our homepage and check out all those, maybe it will help you.

See you in any other articles cheers

References:

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Anup Kumar Dey

A Mechanical Engineer with 19 years of working experience in various renowned MNCs.

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