NC- Numerical Control Programming
Introduction to Conventional Lathe Machine
Content :
Introduction to Manufacturing , History & Processes
Introduction to Conventional Lathe
Introduction to MCMT/CNC
Mechanical Elements of CNC machine
Introduction To CNC Programming
Introduction to SIEMENS 808D controller.
Geometric Dimensioning & Tolerancing
Cutting Tools and Parameter selection Turning
Programming using Siemens standard cycles for Turning
Hands on practical – All standard Cycles of 808D Turning
Introduction To Lathe M/C
Purpose Objectives
• This lesson introduces about Lathe Machine. Upon completion of this lesson, you will be able
aware of:
• Different types of Lathe Machines.
• Specification of Lathe Machine.
• Elements of Lathe Machine.
• Lathe operations.
What is lathe?
o Lathe is the ‘Father’ of all
machine tools.
o Its consist of a single
pointed sharp edge tool
which moves
perpendicularly to the
revolving work piece
axially.
o Work piece is rotating
History
• In the Ancient Greek and Roam the wood workers were use the two trees branch in which they hang
out a big piece of cylindrical wood, Then from the one end a person rotates the cylindrical piece by
using Rope at the Centre side one person was removes the woods outer sole by using single edge
sharp (Knife)cutter.
• By Using this method of removing the material
in 17 Century “Henry maudsley” made a rope operated
Center lathe machine for wood working.
Types of Lathe Machine
There are many different types of lathe machine as per application
• Engine Lathe
• Turret Lathe
• Bench lathe
• Tracer or Copying lathe
• CNC Lathe
Engine Lathe
• It’s a basic, simplest and most versatile lathe.
• Its manually operated.
• Used in training institute, small workshops,
Tool room
Turret Lathe
• This type of lathe machine mostly used in
Mass-production of multi operations
required work-part.
• Equipped with multisided tool post (turret)
on which several different cutting tools
mounted.
• The turret having mostly 8 station or more
than 8 Station as per requirement of tooling
Lathe Size and Capacity
• Designated by largest work diameter that can be swing over lathe ways and generally the maximum
distance between centers
• Manufactured in wide range of sizes
• Most common: 9- to 30- in. swing with capacity of 16 in. to 12 feet between centers
• Typical lathe: 13 in. swing, 6 ft. long bed, 36 in.
• Average metric lathe: 230-330 mm swing and bed length of 500 – 3000 mm
Parts of the Lathe
Tail-Stock
Lathe Accessories
Work-holding/supporting/driving devices Cutting tool holding devices
• Lathe centers, chucks, faceplates • Straight and offset tool holders
• Mandrels, steady and follower rests • Threading tool holders, boring bars
• Lathe dogs, drive plates • Turret-type tool posts
Lathe Centers
• Provides bearing surface
• Support during cutting
• Most common
1. solid Morse taper shank
2. 60deg centers,
3. steel with carbide tips
• Work to be turned between centers must
have center hole drilled in each end
• Care to adjust and lubricate occasionally
Chuck
• Used extensively for holding work for machining operations
• It is used to hold workpiece with radial-symmetry
• Most commonly used lathe chucks
1. Three-jaw universal
2. Four-jaw independent
3. Collet chuck
Three-Jaw Universal Chuck
• Holds round and hexagonal work
• Grasps work quickly and accurate within few thousandths/inch
• Three jaws move simultaneously when adjusted by chuck wrench
• Caused by scroll plate into which all three jaws fit
• Two sets of jaw: outside chucking and inside chucking
Four-Jaw Independent Chuck
• Used to hold round, square, hexagonal,
and irregularly shaped work pieces
• Has four jaws, Each can be adjusted
independently by chuck wrench
• Jaws can be reversed to hold work by
inside diameter
Collet Chuck
• Most accurate chuck
• Used for high-precision work
• Spring collets available to hold round,
square, or hexagon-shaped work pieces
• Each Collet has range of only few thousandths
of an inch over or under size stamped on Collet
Cutting Tools
• Single point cutting tool
Left-Hand Offset Tool holder
• Offset to the right
• Designed for machining work close to chuck or faceplate and cutting left to right
• Designated by letter L
Right-Hand Offset Tool holder
• Offset to the left
• Designed for machining work close to the tailstock and cutting right to left
• Also we can use for facing operations
• Designated by letter R
What is Pre axial and Post axial tool post or Turret?
• In the conventional lathe machine the tool post is situated at the operators side so this is said Pre-
axial tool post , While in the CNC or Non conventional lathe the turret is situated at the front side of
the operator so its said Post-axial turret .
• In the Pre axial turret or tool post we need Right hand tool to machine the work piece and the
spindle is rotates Clockwise direction while in the Post-axial tool post or turret we need Left hand
tool to machine the workpiece and the spindle rotates Anticlockwise direction
Pre axial and Post axial tool post or Turret
Post-axial Turret
Pre-axial Turret
Lathe Operations
Lathe Operations
• Turning: produce straight, conical, curved, or grooved work pieces
• Facing: 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 surfaces
Facing
• Facing is operation to remove the excessive
material from the row material to achieve
clean surface at face side.
• In this operation the tool is faded at axially
parallel to the cylindrical piece from the outer
side of Dia. till more than center of the workpiece.
Contour Turning
• Contour turning is operation of giving
unparalleled shape on the work piece
• Instead of feeding the tool parallel to
the axis of rotation, tool follows a contour
that is other than straight, to create
a Contour form.
Chamfering
• Chamfering is used to give the workpiece good looks & to prevent be damaged at outer dia. side.
Cutoff
• Cut off operation is done on
the work piece to cut out the
machined work part from the
Cylindrical Raw material.
Threading
• Pointed formed tool is fed
linearly across surface of
rotating work part parallel to
axis of rotation at a large feed
rate to create threads.
Drilling
• Used to create a round hole, usually by means of a rotating tool (drill bit) that has two cutting edges
Boring
• In machining, boring is the process of enlarging a hole that has already been drilled (or cast), by
means of a single-point cutting tool
• Boring is used to achieve greater accuracy of the diameter of a hole, and can be used to cut a
tapered hole
• Boring is performed on the inside diameter of an existing hole
• Turning is performed on the outside diameter of an existing cylinder
QUERIES
