PRESENTATION ON LATHE MACHINE

PRINCIPLE OF LATHELathe is a machine, which is used to

remove metal from the workpiece to required shape and size.

COMPONENTS OF LATHE

TYPES OF LATHES• Speed Lathe :

It is the simplest type lathe. It is mainly used

for metal spinning, polishing etc.

• Bench Lathe :

It is small sized engine lathe mounted on

bench. It is used for turning small and light weight

workpiece.

• Tool Room Lathe :

It is used for production of small tools, gauges,

fixtures and accurate parts in tool room.

•Turret Lathe :

These lathes are used in mass production

and for heavy duty workpieces.

•Capsten Lathe :

These lathes are used in mass production

used for light duty workpieces.

•Special Purpose Lathe :

These lathes are modification of engine

lathes developed for machining special types of

workpices.

•Automatic Lathe

•Engine Lathe

•Tracer Lathe

•Computer Controlled lathe

•Swiss Type Automatic Lathe

•Duplicating Lathe

COMPUTER NUMERICALLY CONTROLLED LATHE Computer Numerical Controls (CNC)

Equipped with one or more turrets

Each turret is equipped with a variety of tools

Performs several operations on different surfaces of the

workpiece

TURRET LATHECapable of performing

multiple cutting operations on the same workpiece Turning Boring Drilling Thread cutting Facing

Turret lathes are very versatile

Types of turret lathes Ram-type: ram slides

in a separate base on the saddle

Saddle type: more heavily

constructed Used to machine

large workpeiceces

ENGINE LATHE

BENCH LATHE AUTOMATIC LATHE

PARTS OF LATHE•Bed : Supports all major components

•Carriage: Slides along the ways and consists of the

cross-slide, tool post, apron

•Headstock : Holds the jaws for the work piece,

supplies power to the jaws and has various drive

speeds

•Tailstock : Supports the other end of the workpiece

•Feed Rod and Lead Screw : Feed rod is powered by

a set of gears from the headstock

LATHE BED

•Heavy, rugged casting•Made to support working parts of lathe•On top section are machined ways•Guide and align major parts of lathe

HEADSTOCKClamped on left-hand

end of bed

Headstock spindle

Hollow cylindrical

shaft supported by

bearings

Provides drive through

gears to work-holding

devices

CARRIAGE

Used to move

cutting tool along

lathe bed

Consists of three

main parts

Saddle

Cross-slide

Apron

APRON

16

TAILSTOCK

ACCESSORIESChucks :

Three jaw chuck

Four jaw chuck

Collet chuck

Centres:

Live centre

Dead centre

Tipped centre

Ball centre

Mandrels :

Plain mandrel

Stepped

mandrel

Collared

mandrel

Screwed

mandrel

Chucks :

• Three Jaw Chuck (Self Centering Chuck) :

This chuck is used to hold circular

workpiece and is available in sizes from

100mm to 600 mm.

Four Jaw Chuck (Independent Chuck) :

It is used to hold rectangular,

sqare and irregular shaped workpieces .

ACCESSORIES

Collet Chuck :

Pull poerating rod

Push poerating rod

It is ideal for holding tube

and thin walled workpieces.

Centres:

Live Centre

Dead Centre

Ball Centre

Pipe Centre

Half Centre

Tipped Centre

Mandrels :

Plain Mandrel

Collared Mandrel

Screwed Mnadrel

Stepped Mandrel

LATHE OPERATIONS

•Turing

•Facing

•Boring

•Drilling

•Taper

•Camfering

•Grooving

•Forming

•Reaming

•Undercutting

•Thread

cutting

•Knurling

LATHE OPERATIONS

BORING

Boring produces circular internal profiles in hollow workpieces Boring mills are used for large workpieces Holes can be bored up to 20M if needed See fig. 22.20 Machines are available with a variety of features

Horizontal boring machines Jig borers

TURNINGForces in turning

Cutting force: acts downward on the tool tipThrust force: acts in the longitudinal directionRadial force: acts in the radial direction

Roughing and Finishing CutsRough cut: high speed cut with little regard for

dimensional toleranceFinishing cut: lower feed rate and depth of cut

Tool Materials, Feeds, and Cutting SpeedsCutting Fluids

CONCEPT OF SPEED, FEED AND DEPTH OF CUT

•Cutting speed=Πdn mm/min

1000

•Feed :

• It is expressed in mm/rev

•Depth of cut :

t=D-d mm 2

SINGLE POINT CUTTING TOOL GEOMETRY

•Clearance

•Rake

•End cutting

edge angle

•Side cutting

edge angle