In
the field of Mechanical Engineering Lathe machine acting an important role in
the manufacturing industry. I’m going to discuss the Lathe machine in detail in
this article.
·
A lathe is a
machine that is used to remove undesired metals from the workpiece to give the
wanted shape and size.
·
A lathe machine is
an imperative machine that is used in the industry of metalworking.
·
It works on the
base of a rotating principle workpiece and a fixed cutting tool.
·
The cutting tool
is fed into the workpiece which rotates about its own axis causing the
workpiece to form the desired shape.
·
It is also known
as” the parents of the entire tool family”.
Description
of Lathe Machine
The
machine tool that’s used to remove unwanted metals from the workpiece to give
the asked shape and size so-called the” Lathe machine“, The lathe machine is
also known as a “Center Lathe” because of the two centers between which the job
can be held and rotated.
Functions
of lathe Machine
The
primary function of the Lathe machine is to remove excess material in the form
of chips by rotating the workpiece against stationary cutting tools. This is
skilled by holding the work strongly and rigidly on the machine and then turning
it against the cutting tool that will remove metal from the workpiece. To cut
the material correctly the tool should be harder than the material of the
object, should be rigidly held on the machine, and should be fed or progressed
in a certain way compared to the work.
Main Parts of lathe Machine
In
a lathe machine, every individual part performs an important task. Some
important parts of a lathe machine are as follows:
1. Bed
2. Head
Stock
3. Main
Spindle
4. Tail
Stock
5. Lead
Screw
6. Live
Center
7. Dead
Center
8. Carriage
·
Saddle
·
Apron
·
Tool Post
·
Cross slide
·
Compound Rest
·
Compound Slide
9. Feed
Mechanism
·
Belt Feed
Mechanism
·
Gear Feed
Mechanism
1.
Bed
The
Bed makes the base of a machine.
It
is loaded on the legs of the lathe machine that is bolted to the ground.
It
is prepared with cast iron and its top surface is machined exactly and
correctly.
2.
Head Stock
The
headstock is an important part of a lathe machine that is loaded permanently on
the inner guide – ways at the left-hand side of the bed.
It
consists of the main spindle, a chuck fitted at the spindle nose, a back-gear
drive, and an all-gear drive.
3.
Main Spindle
The
spindle is a hollow cylindrical shaft.
Its
face has a standard mouse taper.
It
is used to hold the live Centre or collet.
The
spindle revolves around main two large bearings contained on the headstock
casting.
The
face end of the spindle is threaded, which is used to hold the chuck, driving
plate, face plate, and catch plate.
It
is known as a spindle nose.
4.
Tail Stock
A
tail stock is located on the inner guide – ways at the right side of the bed
opposite to the headstock.
The
tail stock body is bored and houses the tail stock spindle.
It
tapered holes to obtain the dead Centre or shunk of tools such as a drill or
reamer.
Its
body is prepared with cast iron.
5.
Lead Screw
It
is used to transmit power to the carriage through gear and clutch arrangement
in the carriage apron.
6. Live Center
A
Live Center is loading on bearings and revolves with the work.
Live
centers are used to support or clamp a workpiece.
7. Dead Center
A
dead center may be used to support the workpiece at either the revolving or
fixed end of the machine.
Dead
centers are usually fully hardened to avoid damage to the important coupling
surfaces of the taper and to preserve the 60° angle of the nose.
8. Carriage
A
carriage is located between the headstock and tailstock on the lathe bed
guideways.
It
can be relocated along the bed either towards or away from the headstock.
It
has many parts to support, control, and move the cutting tool.
i. Saddle
It
is H – a shaped casting.
The
saddle connects the pair of bed guideways as a bridge.
It
fits over the bed and slides along the bed between the headstock and the
tailstock.
The
saddle can be moved by providing hand feed or automatic feed.
ii. Apron
The
front portion of a carriage calls an apron. It consists of all control keys.
The
handle operates the carriage. It has a housing, which has a set of gears and a
split nut.
Automatic
feed and threading control are on the apron.
iii. Tool Post
It
is located on the top of the compound slide. It is used to hold the tools
rigidly.
Tools
are chosen according to the type of operation and loaded on the tool post and
adjusted to a suitable working position.
There
are different types of tool posts, which are as follows.
1. Single
Way / Screw Tool Post
2. Four-Way
Tool Post
3. Quick
Change Tool Post
4. British
Type Tool Post
iv. Cross slide
It
is located on the slides and saddle on the dovetail guide – ways at right
angles to the bed guideways.
It
brings a compound slide, compound rest, and tool post.
The
Cross slide hand wheel is revolved to move it at a right angle to the lathe
machine axis.
The
cross slide hand wheel proceeds on its rim to enable to give the known amount
of feed as accurately as 0.05 mm.
v.
Compound Rest
It
is a part that connects to the compound slide and cross slide.
It
is loaded on the cross slide by the tongue and groove joint.
The
compound rest can be rotated to the required angle while tapers turning.
A
top slide called the compound slide is attached to the compound rest by a
dovetail joint.
vi.
Compound Slide
A
compound slide is a T-shaped rounded slot that is fixed with a cross slide
upper surface by two bolts, which is associated with a micrometer sleeve and
screw handle with the outer edge of the screw.
Taper
turning can be possible by setting the compound slide at half of the required
angle.
The
slide is only used for short job taper turning.
The
automatic feed is not possible in the compound slide.
9.
Feed Mechanism
There
is a number of mechanisms to make the cross slide and carriage move
automatically to change the direction of their movement.
Some
important feed mechanisms are as follows:
i. Belt Feed Mechanism
The
belt feed mechanism is commonly used in the oldest lathe machines.
In
this, a cone-stepped pulley is used to provide the different types of speed.
To
change the speed, a lever is used to slide the belt from one pulley to another.
The
belt feed mechanism has a demerit of the belt slipping in the pulley changing
process.
ii. Gear Feed Mechanism
In
the gear feed mechanism, the power is transmitted from the spindle to the lead
screw or feed rod with the power gear train.
Gear
1 is located at the back side of the spindle and the tumbler bracket contains
gears 2, 3, 4, and 5.
A
lever controls the bracket. This bracket is pivoted about the axis of the stud
gear.
This
position of the bracket can be arranged in three different stages namely:
1. Neutral
Position
2. Forward
Position
3. Reverse
Position
4. Working
Principle of lathe machine
Principle
·
A lathe is a
machine that use to remove undesired materials from a workpiece in the form of
chips with the help of a tool that moves across the workpiece and can be fed
deep into the workpiece.
·
When the device is
traveled parallel to the workpiece then the cylindrical surface is shaped.
·
If the tool is
traveled inclined to the axis then it forms a tapered surface and so known as
taper turning.
Working
·
It grips the work
between two supports so known as centers.
·
A faceplate or
Chuck is used to hold the work.
·
Faceplate or Chuck
are loaded on the machine spindle.
·
The cutting tool
is held with the help of a Tool post.
·
The movement of
the job is revolving around the spindle axis.
·
Against the
rotating work, the tool is fed.
·
The tool travels
either parallel or in inclination to the work axis.
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