In the last session, we had discussed NC Machine in detail whereas, in today's session, we will discuss on CNC Machine along with its Definition, Types, Components, Working, Function, Applications, Advantages, and Disadvantages. So let's start with the definition of CNC Machine.
If Every axis of a machine tool is controlled by using a mini-computer [which can run using Coding (G-Codes & M-Codes)] called as Computer Numerical Controlled Machine(CNC).
The different types of CNC Machines are as follows.
So let me explain one by one.
Mostly the configuration of Milling machines is of 3 axes to 6 axes. In this machine, the components are to be machined with the help of Multi-point Milling Cutter.
I have already written about Conventional Milling Machine and you can check it too.
This machine is used to create holes, create bores, and also create slots in the workpiece and can also find its application in the creation of Spur gears.
As for the CNC Milling Machine is concerned, we need to create a part program in the form of G Codes and M Codes and it is inserted into the brain of CNC Machine. It can do its operation based on the work allocation in the program w.r.t. the coordinates.
The efficiency of the CNC Milling machine is very high compared to the conventional Milling Machine.
As the name indicates that the cutting operation is carried out by means of laser called 'Laser Cutting'. If this operation is carried out on CNC called CNC Laser Cutting Machine.
The efficiency is very high compared to manual laser cutting.
It is generally used to cut the metal sheets.
They are designed to cut the tougher materials and it is similar to Plasma Cutting where instead of laser torch, the plasma torch is used to cut the materials.
Laser Cutting CNC Machines uses three types of Lasers. They are neodymium (Nd), CO2, or yttrium-aluminum-garnet (Nd: YAG).
Similar to CNC Laser cutting machines, Plasma Cutting machines are used to cut the materials.
They use a Plasma Torch to penetrate into the tougher materials which are not possible by laser cutting machines.
The temperature of the plasma is in excess of 20000 degrees Centigrade.
Before knowing about the CNC Lathe machine, you should aware of the parts and the working of Conventional Lathe Machine in detail so that you can understand the CNC Lathe machine effectively.
Lets know about CNC first...
CNC stands for Computer Numerical Control.
It is one of the machinery which was widely used in various industries for faster production of components.
Here, the program is generated by a team of engineers and that can be stored in the memory unit of the system.
There is no need to change the code once you added it to the machine unit for the repetitive purpose.
A semi-skilled operator is required to operate the working of lathe machine.
EDM stands for Electrical Discharge Machining which is used to cut the tougher materials and this EDM has the property of high MRR (Material Removal Rate).
Before knowing about CNC EDM, you should have the basic awareness of Conventional Electrical Discharge Machining such that you can understand the CNC EDM effectively.
CNC EDM is also known as the Spark CNC Machine that uses electrical sparks for removing the material from the surface of the workpiece.
The component is to be placed in between the work table which acts as anode and the tool electrode which acts as a cathode. Due to the excessive power, the dielectric fluid ionizes and the power is transmitted via the fluid to the workpiece and thereby material removal takes place.
As the entire operation can be carried out by means of a program in the CNC Machine, the components produced has a high surface finish compared to the traditional machines.
It is generally used for carpentry work i.e. making of interior and exterior decorations, musical instruments, furniture, etc.
It can works as per the sketch or design given to it in the form of program.
It executes high surface finish.
It is a machine that is capable of performing in 5-axes of the workpiece. It is generally used for making sculptures, larger turbines, etc.
Out of the 5-axes, 3 are translational axis i.e. X,Y and Z axis and the reast two axes are A and B which give the cutting tool a multidirectional approach.
As the name implies, additive manufacturing adds the material to create a 3D object.
3D Printing is also known as Additive Manufacturing in which the model of an object has to be created in any Modelling Software and has to save in the format of STL.
This type of CNC Machines is generally used in the construction of computers, tablets, cell phones, etc.
It consists of several nozzles that can pick up the electrical components and place them somewhere with respect to the need of the operator.
Similarly, it can does pick and place operation for other components too.
This is a detailed explanation of the different types of CNC Machines. Now let's discuss the components of the CNC machine in detail.
A CNC Machine consists of following parts:
Let me explain all these components.
MCU is working as a brain of human beings i.e. MCU is taking input information from the input devices, analyze the data, and all these decisions will be implemented by using output devices available in the CNC machine.
The Input Information is in the form of the decimal system and as the machine can understand only the Binary System of information, a device is required in MCU to convert the decimal to binary and vice versa, and that device are called as Arithmetic Logic Unit(ALU).
It is the device used for converting Electrical energy into Mechanical energy which is required for traveling the axis.
For example, Electric motor.
Here we can use Servo Motor as the drive unit in CNC Machining.
It is also working similar to that of stepper motor but additionally, there is a quick action Braking System available in the motor so that whenever the power supply is getting stopped, the Braking System will be activated and stops all the moving parts.
Hence it is possible to get the high positional accuracy of the machine. Because the Servo Motors are not available at the time of development of the NC machine, the stepper motor can be used as a drive unit.
It is a Displacement Measuring Equipment used to measure the actual distance traveled by the Axis and giving it as a feedback to the MCU and the MCU will compare the distance traveled by the axis with the distance to be traveled and determines the difference in distance.
The MCU will calculate the no.of pulses and send it to the drive unit. This process continues in the form of a cycle.
Feedback Device→MCU→Drive Unit.
Due to the usage of the minicomputer, the program will be fed into the machine through a keyboard and kept in the memory of a mini-computer in the form of a software program.
Due to the above program, the operation will perform without the intervention of the operator and the dimensional accuracy is also high.
Even though the above parts are present in the CNC machine, still the manual interventions are required for switching ON and OFF, loading and unloading of the workpiece, etc. called manual controls.
These are the CNC Machine Parts which are explained in a detailed manner.
The working of the CNC Machine is based on mainly two software. Among that one is CAD (Computer-Aided Design) and the other is CAM (Computer Aided Manufacturing).
CAD software improves the quality of design and creates a separate database for manufacturing whereas CAM software involves programs that are written in the form of G Codes and M Codes.
The components of CNC machine which increases the efficiency are Input devices, Machine Control unit, Driving system, Machine tool (any machine like drilling, milling, etc.), and Feedback devices.
The functions of CNC Machines are as follows.
The Applications of CNC Machines are as follows.
These are some advantages of CNC Machine:
The Disadvantages of CNC Machine are as follows.
Before knowing about the G Codes and M Codes, we need to know about Part Programming.
Part Programming is not a language programming but it is a coded programming method used for writing the programs for the manufacturing of given components.
Part Programming uses standard codes and code means the name given for the program written for a standard measurement of the tool. These codes are used in part programming.
G-Codes Stands for General Purpose Codes and M-codes Stands for Miscellaneous or Machine Codes. A minimum of 2 marks will come from this region.
So let's start with G Code first!
Note: Even though the incremental mode of programming is easy to write and modify but according to Indian conditions, we prefer to use the absolute mode of programming only because during the running of the program for producing the components, if the power failure occurs, after restoring the power, it is very easy to identify where the program has got stopped if it is an absolute mode of the program.
The remaining G-Codes required in Part Programming are as follows:
Now let see some important M Code too,
M codes play a vital role in the CNC Part Programming. Majorly M codes are used to write the main programs and Sub-Programmes in CNC Part Programming. Along with these M Codes, I will be writing about the Main Programmes and Subprograms which are used in CNC Part Programming.
However, 100 M codes are starting from (M00 to M99). But only 14 M codes that are important for the GATE point of View are presented below.
So this is my complete explanation regarding CNC Machine Tool, I hope you liked this article, if you have any doubts feel free to post in the comment section, I will get back to you within 24hrs.
These M codes are used to control the actual machine workings.
G-code contains the information to position a tool to do the actual work.
If Every axis of a machine tool is controlled by using a mini computer[which can run using Coding (G-Codes & M-Codes)] called as Computer Numerical Controlled Machine(CNC).
CNC machines are used to increase the efficiency and decrease the cost, and time compared to conventional machines.
John T. Parsons is the father of the CNC machine.
More Resources:NC Machine