INTRODUCTION TO INTRODUCTION TO MACHINE TOOLSMACHINE TOOLS

MMACHINEACHINE TTOOLSOOLS

A machine tool is a power A machine tool is a power driven apparatus driven apparatus designed to perform designed to perform certain metal removing certain metal removing operations & produce a operations & produce a desired shape on a desired shape on a surface being machined.surface being machined.

ExamplesExamples

Lathe MachineLathe Machine Drilling MachineDrilling Machine Milling MachineMilling Machine Grinding MachineGrinding Machine

ELEMENTS OF CONSTRUCTIONELEMENTS OF CONSTRUCTION

A machine tool is composed of A machine tool is composed of different elements which are different elements which are stated as follow;stated as follow;

Bed, Body or frame.Bed, Body or frame. Head StokeHead Stoke WaysWays Main spindleMain spindle ColumnColumn Tail StokeTail Stoke Work & tool holding devices.Work & tool holding devices.

BBED, ED, BBODY ODY & F& FRAMERAME

It is the main frame work of a It is the main frame work of a machine that carries all other machine that carries all other components, included in components, included in design.design.

Base of bed is provided with Base of bed is provided with lugs & holes for bolting the lugs & holes for bolting the machine down.machine down.

BBED, ED, BBODY ODY & F& FRAMERAME

Material of bed should be Material of bed should be Vibration absorbing Because Vibration absorbing Because vibrations are set up during the vibrations are set up during the working of machine.working of machine.

Structure of bed should be solid Structure of bed should be solid and rigid to avoid permanent and rigid to avoid permanent deformation.deformation.

HHEADEAD SSTOKETOKE

It drives & provide feed It drives & provide feed to the cutting tool or to the cutting tool or rotates the work rotates the work component.component.

WWAYSAYS

These are long machined These are long machined strips or grooves for carrying strips or grooves for carrying & guiding a slide or table.& guiding a slide or table.

Using ways, bed allows Using ways, bed allows linear movement to the linear movement to the table.table.

MMAINAIN S SPINDLEPINDLE

The shaft that transmits power The shaft that transmits power from motor to the work piece from motor to the work piece or tool is called as main or tool is called as main spindle.spindle.

It can be driven by;It can be driven by;

1)1) BeltBelt

2)2) GearsGears

CCOLUMNOLUMN

In some vertical shape In some vertical shape machines extra support is machines extra support is required so column is required so column is present to provide present to provide support to Head Stoke.support to Head Stoke.

TTAIL AIL SSTOCKTOCK

Some times the work piece is Some times the work piece is long as a result of this accurate long as a result of this accurate machining can’t be performed machining can’t be performed without supporting at both ends.without supporting at both ends.

It provides support at end to the It provides support at end to the long piece. long piece.

WWORKORK & T & TOOLOOL H HOLDINGOLDING DDEVICESEVICES In order to maintain the In order to maintain the

accuracy of machining process accuracy of machining process it is quite necessary to hold the it is quite necessary to hold the work piece as well as tool.work piece as well as tool.

For rapid & high quantity For rapid & high quantity productions these devices are productions these devices are necessary.necessary.

ExamplesExamples

1)3 jaw chuck2)4 jaw chuck

IINTRODUCTIONNTRODUCTION T TOO NC NC && CNC CNC

IINTRODUCTIONNTRODUCTION

Due to the increasing demand of Due to the increasing demand of production quantity & quality, production quantity & quality, manufacturers are moving manufacturers are moving towards new sophisticated towards new sophisticated equipment & machinery. equipment & machinery.

The need is to transfer The need is to transfer instructions from man to the instructions from man to the machine through automatic machine through automatic devices.devices.

Manual operators are being Manual operators are being replaced by automatic devices.replaced by automatic devices.

IINTRODUCTIONNTRODUCTION

““NUMERICAL” means, NUMERICAL” means, expressing something by expressing something by numbers.numbers.

““CONTROL” is exercise of CONTROL” is exercise of directing & guiding power over directing & guiding power over something.something.

““NUMERICAL CONTROL” is NUMERICAL CONTROL” is directing power over something directing power over something by using numbers.by using numbers.

BASIC COMPONENTS OF BASIC COMPONENTS OF NC SYSTEMNC SYSTEM

The main components of a NC The main components of a NC machine tool are;machine tool are;

Program of instructions.Program of instructions. Machine Control Unit.Machine Control Unit. Machine tool or processing Machine tool or processing

equipment.equipment.

ProgramMachine Control

Unit

Feed back

PROGRAM OF PROGRAM OF INSTRUCTIONSINSTRUCTIONS It is detailed set of directions It is detailed set of directions

which tells the machine tool which tells the machine tool what to do & in what sequence.what to do & in what sequence.

The program is fed to the The program is fed to the machine control unit by some machine control unit by some input mediainput media

e.g.e.g.

- Magnetic Tapes & floppy disks.- Magnetic Tapes & floppy disks.

MACHINE CONTROL UNITMACHINE CONTROL UNIT

It consists of the electronics & It consists of the electronics & hardware that read & interpret the hardware that read & interpret the program of instructions and convert it program of instructions and convert it into mechanical action of the machine into mechanical action of the machine tool. The elements of this units are;tool. The elements of this units are;

ReaderReader Signal output channels to machine tool.Signal output channels to machine tool. Feedback output channels from Feedback output channels from

Machine tool.Machine tool. Sequence control Unit.Sequence control Unit.

MACHINE TOOLMACHINE TOOL

It performs the useful It performs the useful mechanical work.mechanical work.

It is simple machine tool ( lathe) It is simple machine tool ( lathe) that is integrated with control that is integrated with control unit.unit.

CNC Machine ToolsCNC Machine Tools

Computer Numerical Control Computer Numerical Control (CNC) - A numerical control (CNC) - A numerical control system in which the data system in which the data handling, control sequences, handling, control sequences, and response to input is and response to input is determined by an on-board determined by an on-board computer system at the machine computer system at the machine tool. tool.

CNCCNC

AdvantagesAdvantages Increased Program storage capability at the Increased Program storage capability at the

machine toolmachine tool Program editing at the machine toolProgram editing at the machine tool systems upgrades possiblesystems upgrades possible Tool path verificationTool path verification