In this article, we explained completely about
1) Definition of Numerical control,
2)Basic components
3) classification of Nc machine
4) Advantages and disadvantages
Definition of Numerical control
Numerical control is defined as a form of programmable automation, it is the process of controlled by numbers, symbols, letters.
In this numerical control, the number forms a program of instruction designed for a particular job.
In case ( job or work ) changes the program also changes.
The NC is used in the metal machining process.
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Basic components of Numerical Control
Any control system has consist of several components basically
In numerical control has consisted of three basic components.
Machine control unit
Program of instruction
Machine tool
Program
The program is detailed step by step gives instructions that tell the machine when to do, what to do. These programs are completely in the coding process. These codes are in numerical or symbolic form.
In this Nc, machines punched tape acts as an input medium. the other forms of input media are punched cards, magnetic tape, paper tape..
Also read; mechanical engineering
The machine control unit(M.C.U).
It is another component of the Nc system. Its main uses convert the instructions from the program into Mechanical actions of the tool.
This machine control unit has consisted of the following elements are.
Tape reader, Data buffer, feedback channels.
Tape reader It is an electromechanical device.
Its main purpose has contained the total program of instruction.
Data buffer
Feedback channel
It has to proper instructions feedback gives to the Nc system
Machine tool.
It is one of the parts of the Nc system which performs useful work.
It consists of the work table. And motors necessary to drive them.
Classification of Nc machine tool.
The Nc machine-classified into
1) To motion or position control system
Point to point system
Stright line system
Contouring control system.
2) Tool control system
Open-loop system
Closed-loop system
3) To structure the control system
Numerical control
Computer numerical control system
Directive numerical control system
4) Based on the power supply
Electrical, Hydraulic
5) To the program
Absolute
Incremental
Main features of Numerical Control system
Punched tape:
It is widely used for feeding the program. Normally the tape will be 25 mm wide and capacity for storing 10 characters.
This punched tape is generally punched by a punching device.
Tape reader.
This device used for reading the coded language from the program of instructions .the coded instructions transformed into electrical signals utilize for
Controlling various machines.
Machine Control Unit.
It has consist of mainly two parts
Data processing unit.
Control loop unit (CLU)
(DPU ) Data processing unit
Its main purpose is to decode the information received from the tape and gives the data to the CLU.
Advantages of Nc system
- Reduce mfg lead time
- Improves quality
- Reduce inventory on Nc system
- Reduce inspection process.
- Manufacturing flexibility
Dis advantages of Numerical control
- Investigating is high.
- Maintaining is also high.
- Skilled persons required.
What are the steps manufacturing of NC system?
In the manufacturing of the Nc system mainly following steps are involved.
Processing planning
Part program.
Tape preparation.
Tape verification.
Production
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