2. Learning Objectives The students shall be able to understand
the followingDefine a lathe Explain the construction of
latheDescribe the types of lathe machine Explain the operations of
lathe machine 3. Contents Introduction to centre latheConstruction
of centre lathe types of lathe machine Operations of lathe 4.
MOTIVATION 5. Introduction i). History ii). Work principle iii).
Size of lathe 6. LATHE MACHINE Presented by Tauqeer ahmad khan 7.
History 8. i) History The origin of turning dates to around 1300BC
when the Egyptians first developed a twoperson lathe. One person
would turn the wood work piece with a rope while the other used a
sharp tool to cut shapes in the woodThe Romans improved the
Egyptian design with the addition of a turning bow. Early bow
lathes were also developed and used in Germany, France and Britain.
9. Working principle 10. Tailstock center (Dead Centre)Headstock
center (Live Centre)Working Principle Workpiece Tool postWorkpiece
N (rev/min)Chip ToolDS peripheral speed (m/min) 10 11. Size of
lathe Depends upon following pointsMain pointsSwing (maximum
diameter of job that can swing on it without touching bed ways
)Distance between centres of lathe 12. Size of lathe 13. Types 14.
Types of latheCNC latheManually operatedSpecial purposeproduction
Turret lathe Capstan latheBench lathe Tracer latheGeneral
purposeCentre lathe Tool room lathe,etc 15. Centre lathe Most
frequently used lathe Heavy duty power drive for most tool
movements Size range 12x24 to 24x48 - can be larger 16. Bench Lathe
A bench top model usually of lowpower used to make precision
machine small work pieces 17. Tool room lathe Look like engine
lathe Greater accuracy More versatility Wider range of speeds and
feeds 18. Turret Capable 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 It is
production lathe Hex turret replaces tailstock Multiple tools set
to machine part Turret Head High production rates Still may require
some operator skill 19. Capstan lathe It is production lathe Used
for light duty work pieces Small in size as compared to turret
lathe It also have turret that replaces tailstock Multiple tools
set to machine part Still may require some operator skillTurret
Head 20. Tracer/copy lathe Tracer piece Hydraulic attachment used
to copy the shape of a part from a master. lathe that has the
ability to follow a template to copy a shape or contour. Machine
tools with attachments Capable of turning parts with various
contours A tracer finger follows the template and guides the
cutting tool 21. Automatic lathe An automatic lathe is a lathe
(usually a metalworking lathe) whose actions are controlled
automatically. Although all electronically controlled (CNC) lathes
are automatic, they are usually not called by that name, as
explained under "General nomenclature". The first kinds of
automatic lathes were mechanically automated ones 22. CNC lathe
Computer controlled Wide variety of process capability multiple
axis Indexing and contouring head On- line and off- line
programming available 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 work
pieceMachine UnitNC controller 23. Construction of lathe 24. Lathe
Basics Spindle NoseTailstock Spindle ClampTool Post Compound
RestHEADSTOCKTAILSTOCKSaddleFeed Reverse LeverFeed Change Lever
Lead ScrewBED WAYS APRONGear BoxCarriage Hand Wheel Motor
DriveFrictionclutch Control Cross SlideHalf Nut LeverBed 25. Lathe
Operations 26. Lathe Operations Turning: produce straight, conical,
curved, or grooved work piecesFacing: to produce a flat surface at
the end of the part or for making face grooves. Boring: to enlarge
a hole or cylindrical cavity made by a previous process or to
produce circular internal grooves. Drilling: to produce a hole by
fixing a drill in the tailstock Threading: to produce external or
internal threads Knurling: to produce a regularly shaped roughness
on cylindrical surfaces26 27. Lathe Operations27 28. Turning ..
Cylindrical jobCutting speedWorkpiece Depth of cut (d) Machined
surfaceNChuckFeed ToolChip Depth of cut 29. Facing ChuckFlat
Surface/Reduce lengthWorkpiece d Machined FaceCutting speedDepth of
cut ToolFeed 30. Facing operation 31. Eccentric Turning 4-jaw
chuckAxis of jobAxis Cutting speedEccentric peg (to be turned) 32.
Knurling Knurled surface Cutting speed Feed Knurling tool Tool
postMovement for depth 33. Grooving .. Shape produced by form
toolForm toolFeed or depth of cutGrooveGrooving tool 34. Parting
..Parting toolFeed 35. ChamferingChamferFeed Chamfering tool 36.
Taper Turning Taper:D1 D2 2Ltan90D1B AD2C L 37. Drilling Drill
cutting tool held in TS feed from TSQuill clamp moving Drill quill
Tail stock Feed Tail stock clamp 38. Contour Turning Instead of
feeding the tool parallel to the axis of rotation, tool follows a
contour that is not necessarily straight (thus creating a contoured
form).Figure ..contour turning 39. Threading Pointed form tool is
fed linearly across surface of rotating workpart parallel to axis
of rotation at a large feed rate, thus creating threadsFigure;
threading 40. Summary. Introduction to centre lathe Construction of
centre lathetypes of lathe machines Operations of lathe 41. Feed
back/Evaluation 1.Lathe is used to turni)Square shape ii)
cylindrical shape iii) irregular shape2 Size of lathe depends upon
following i) Size of chuck and length of bed ii) Distance b/w
centres and length of bed iii) Its weight & length of bed iv)
distance b/w centres & swing diameter of job to be held3. What
are the basic difference b/w turret lathe and capstan lathe i)
Sizeii) precisioniii) by turret head position iv) i,iii
