lathe_machine_mechanical_worshop_imp.ppt

This is related to lathe machine

1. Introduction of Lathe
Machine
(Machine Shop)
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2. Introduction to Machine Shop
■The shop where most of the work is performed
on different machines is called machine shop.
■Different machines used in machine shop are:
–Lathe Machine
–Milling Machine
–Shaper Machine
–Planning Machine
–Grinding Machine
–Drilling Machine

3. Introduction to Machine Shop
■Machine shop is a place where
material removal processes are
carried out.
■A tool which performs the material
removal processes on machines is
known as machine tool.
■The relative motion between cutting
tool and workpiece causes cutting
operation which generates the part
of desired shape, size and finish.

4. Introduction to Lathe Machine
■Lathe is a machine, which removes the
metal from a piece of work to the required
shape & size (cylindrical shapes)
■The workpiece is placed between two
centers of machine, the driving center is
called head stock. The other one is a dead
center called tailstock.

5. Introduction to Lathe Machine
■The job is securely and rigidly held in the
chuck or in between centers on the lathe
machine and then turn it against a single point
cutting tool which will remove metal from the
job in the form of chips.
■Engine Lathe

6. Lathe
Lathe machine has three basic parts:
Head Stock
Tail Stock
Carriage

7. Principal parts of an Center lathe

8. Principal parts of an Center lathe
1.Bed: The bed is a heavy, rugged casting and it
carries the headstock and tailstock for supporting
the work piece and provides a base for the
movement of carriage assembly, which carries the
tool.
2.Headstock: Headstock of a lathe is the power
source for the machine tool. The prime mover
(motor) is usually fitted at the bottom side and is
connected to the spindle of lathe using flat or V-
belt on stepped pulleys. Gears are also used.

9. Principal parts of an Center lathe
3.Tailstock: The tailstock is a movable casting located
opposite the headstock on the ways of the bed. The
tailstock can slide along the bed to accommodate
different lengths of work piece between the centers.
A tailstock clamp is provided to lock the tailstock at
any desired position. Cuttings tools hold.

10. Principal parts of an Center lathe
4.Carriage: The carriage is located between the
headstock and tailstock and serves the purpose of
supporting, guiding and feeding the tool against the
job during operation. The main parts of carriage are:
–Saddle
–Cross slide
–Compound rest
–Tool post
–Apron

11. Principal parts of an Center lathe
5.Lead screw: A lead screw also known as a power
screw is a screw, moves the carriage by a precise
increment for every rotation of the screw. The lead
screw is made with square, acme, or buttress type
threads.
6.Quick-Change Gearbox: The quick-change
gearbox, containing a number of different sized
gears, provides the feed rod and lead screw with
various speeds for turning and thread-cutting
operations.

12. Lathe operations
1.Facing
2.Centering
3.Turning
4.Parting
5.Drilling
6.Boring
The engine lathe is an accurate and versatile
machine, on which many operations can be done
on this machine. These operations are:
7.Reaming
8.Knurling
9.Forming
10. Chamfering
11.Thread cutting

13. Lathe operations
■Facing is the process of removing
metal from the end of a work piece
by using a single point cutting tool,
to produce a flat surface.
■Turning is the process of removal
of metal from the outer diameter of
a rotating cylindrical work piece.
Turning is used to reduce the
diameter of the work piece, usually
to a specified dimension.

14. Lathe operations
■Centering (center drilling) is the
process of providing a small tapered
hole at end of a work piece by using
centering tool, which can helpful to
accommodate and support a running
center in the tailstock.
■Drilling is the process of making
holes at the end face of the work
piece by using a drill bit, fixed with
drill chuck, clamped at tailstock

15. Lathe operations
■Boring is the process of enlarging a
hole that has already been drilled or
cast, by using a single point cutting
tool.
■Knurling is a process of making
easy-to-grip geometric pattern on a
finished outer surface of work
pieces like handles, knobs, rollers,
etc. to hold them firmly.

16. Lathe operations
■Parting is the process of cut off the
work piece at a specific length by
using a parting tool. It is normally
used to remove the finished end of a
work piece from the bar stock that is
clamped in the chuck.
■Forming is a process of produces a
convex, concave or any irregular
profile on the work piece by using a
form tool.

17. Lathe operations
■Thread cutting is a process of
cutting very accurate screw threads
by using a single point cutting tool,
which is the process of guiding the
linear motion of the tool bit in a
precisely known ratio to the rotating
motion of the work piece
■Chamfering is a process of
bevelling the extreme end of a work
piece. This is done to remove the
burrs and sharp edges from the
extreme end of the work piece

18. Lathe operations
■Taper Turning an operation
performed on a lathe that feeds a
tool at an angle to the length of the
workpiece in order to create a
conical shape.

19. Work Holding Devices
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20. Three jaw chuck
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- For holding cylindrical
stock centered.
- The jaws are moved
simultaneously by screwing
one jaw.
Four-Jaw Chuck
-This is independent chuck
generally has four jaws
-Used to grip the
workpiece of shape other
than cylindrical.
-Used to hold irregularly
shaped parts
-Off-center parts
-Cams, Camshafts and
Similar parts.

21. Chuck
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three jaw chuck
‑

22. Rests
■A rest is a mechanical device to support a long work
piece when it is turned between centers or by a chuck.
■It is placed at some intermediate point to prevent the
work piece from bending due to its own weight and
vibrations setup due to the cutting force.
■There are two different types of rests.
–Steady rest
–Follower rest

23. Rests
■Steady Rest

24. Rests
■Follower Rest

25. Machining
Variety of work materials
can be machined
–Most frequently applied to
metals
Variety of part shapes and
special geometry features
possible, such as:
Screw threads
Accurate round holes
Very straight edges and flat
surfaces
Good dimensional accuracy
and surface finish
Wasteful of material
Chips generated in
machining are wasted
material, at least in the unit
operation
Time consuming
A machining operation
generally takes more time to
shape a given part than
alternative shaping
processes, such as casting,
powder metallurgy, or
forming
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