INDUSTRIAL TRAINING

AT

TATA STEEL

JAMSHEDPUR

GOVERNMENT ENGINEERING COLLEGE AJMER

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PRESENTED BY:

MD. FAIZANVII SEM. ( EIC)COLLEGE NO. 08EI28

INTRODUCTION Established in 1907 by J.N.Tata. Formerly known as TATA IRON AND STEEL

COMPANY LIMITED(TISCO) World’s 6th Largest Steel making company. 28.1 million p.a. of crude steel production

capacity. Products: Steel, Blast furnaces,EOT cranes,

Automobiles, Machines etc. Headquartered in Jamshedpur, Jharkhand and

registered office in Mumbai ,India

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INTRODUCTION OF NC AND CNC

NC stands for Numerical Control CNC is self contained NC system with a

dedicated computer. Control a machine by programs or set of

instructions. Widely used for manufacturing system like

Machine Tools, Welders, And Laser Beam Cutters

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Motivation and Uses

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To manufacture complex curved geometries in 2D or 3D was extremely expensive by mechanical

Machining components with repeatable accuracy

Unmanned machining operations

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ADVANTAGES DISADVANTAGES

Easier to program

Easy storage of existing

programs

Easy to change a program

Avoids human errors

NC machines are safer to operate

Complex geometry is produced

as cheaply as simple ones

Usually generates closer

tolerances than manual machines

Increase in electrical maintenance.

Increase in initial investment.

Training of existing workforce.

Not cost-effective for low-level production on simple parts

CNC SYSTEM ELEMENTS

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A typical CNC system consists of the following six elements

Part program Program input device Machine control unit Drive system Machine tool Feedback system

NC SYSTEM ELEMENTS

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OPERATIONAL FEATURES OF CNC MACHINES

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PART PROGRAM

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A part program is a series of coded instructions required to produce a part as in the following example

N10 G01 X5.0 Y2.5 F15.0    |        |        |        | |    |    |        |        |    Feed rate (15 in/min)     |      |        |        Y-coordinate (2.5")     |        |     X-coordinate (5.0")     |      Linear interpolation mode   Sequence number

BLOCK

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Block is the smallest part of the programme.The block is composed of words and always ends with the characters “END OF BLOCK”.

A block contains the following WORDS :

Sequence / Block number __________________________ N

Preparatory Functions _____________________________ G

Dimensions _____________________________________ X, Y, Z

Arc Center Offset _________________________________ I, J, K

Feed Function ___________________________________ F

Speed Function __________________________________ S

Tool Function ____________________________________ T

Miscellaneous Function ____________________________ M

PROGRAM INPUT DEVICE

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The program input device is the mechanism for part programs to be entered into the CNC control.

The most commonly used program input devices are keyboards, punched tape reader, throgh RS 232 serial ports and networks.

MACHINE CONTROL UNIT

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It is used to perform the following functions:

Read coded instructions Decode coded instructions Implement interpolations (linear, circular,

and helical) to generate axis motion commands

Feed axis motion commands to the amplifier circuits for driving the axis mechanisms

Receive the feedback signals of position and speed for each drive axis

Implement auxiliary control functions such as coolant or spindle on/off, and tool change

TYPES OF CNC CONTROL SYSTEMS

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Open-loop control Closed-loop control

DRIVE SYSTEMA drive system consists of :amplifier circuits,stepping motors or servomotors ball lead-screws

Open Loop v/s Closed Loop controls

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Elements of CNC machines

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1. Terminal Connector (TC)

The Terminal Box provides easy, reliable connections for wires and cables

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2. POTENTIOMETERS

FEEDBACK DEVICES

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3. Limit Switches

Interlocks a mechanical motion or position with an electrical circuit.

Most common limit switch is the single-pole contact block with one NO and one NC set of contacts

4. PUSH BUTTONS

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Simple switch mechanism for controlling a process.

Colour coded: red(stop) green (start)

5. CONTACTOR

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Used for switching a power circuit of higher ampere ratings.

Electromagnet provides driving force to close the contact.

Enclosed in insulating material for protection.

Conclusion

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• Learned about the basic electrical components.

• Learn different circuits used in CNC machine.

• Introduction to CNC machine.

• Basic programming of CNC machine.

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