What is a lathe machine?


Lathe machine


A Lathe Machine is one of the most important material removal

methods in the technology of manufacturing. It is basically a collection

of material-working processes that involve other processes. A lathe is a

machine tool used principally for shaping pieces of metal and wood or

other materials by causing the work piece to be held and turned by the

lathe while a tool bit is advanced into the work on the cutting function.

A powerful machine that is useful to shape wood in machining is the

lathe machine.


Principle of lathe machine


The lathe is a machine tool which holds the w/p B/w two rigid & strong

called centers or in a chuck or in face plate which revolves. The cutting

tool is held and fed against the revolving work. Cutting tool fed either

parallel or at right angles to the axis of w/p or may also at an angle.


Modes of use


When a workpiece is fixed between the headstock and the tail-stock, it is

said to be "between centers". When a workpiece is supported at both

ends, it is more stable, and more force may be applied to the workpiece,

via tools, at a right angle to the axis of rotation, without fear that the

workpiece may break loose.

When a workpiece is fixed only to the spindle at the headstock end, the

work is said to be "face work". When a workpiece is supported in this

manner, less force may be applied to the workpiece, via tools, at a right

angle to the axis of rotation, lest the workpiece rip free. Thus, most

work must be done axially, towards the headstock, or at right angles,

but gently. When a workpiece is mounted with a certain axis of rotation,

worked, then remounted with a new axis of rotation, this is referred to

as

"eccentric turning" or "multi-axis turning". The result is that various

cross sections of the workpiece are rotationally symmetric, but the

workpiece as a whole is not rotationally symmetric. This technique is

used for camshafts, various types of chair legs.


Parts of Lathe Machine


The following are the main parts of lathe machine : –


1. Bed

2. headstock

3. Carriage 4. Feed mechanism

5. Tailstock

6. Screw or thread cutting mechanism

7. Feed rod

8. Lead screw


Types of Lathe Machines


Following are the seven different types of lathe machine:

1. Speed Lathe Machine.

2. Engine Lathe Machine

3. Lathe Machine

4. Toolroom Lathe Machine

5. Capstan and Turret Lathe Machine

6. Special purpose lathe machines

7. Automatic Lathe Machine

8. CNC lathe machine


● 1. Speed Lathe Machine


These types of lathe machines are simple in construction. It has a bed,

headstock, tailstock, and tool post mounted on the adjustable slide.

There is no feed box lead screw or carriage.

The tool is mounted on the adjustable slide and is fed into the work

purely by hand control. This characteristic of the lathe machines has the

speed ranges from 1200 to 3600 rpm. The headstock construction is very

simple and has only 2 or 3 spindle speeds available.


● 2. Engine Lathe Machine


Engine lathe is the most widely used lathe machine. These machines are

driven by the gear mechanism or pulley mechanism. The name engine

lathe is given because of the earlier lathe were driven by steam engines.

Unlike the speed lathe, the engine lathe can feed the cutting tool both in

the cross and longitudinal direction with reference to the lathe axis with

the help of a carriage feed and leadscrew. These types of lathe machines

are still used in workshops and many industries. It has three types

Belt-driven, Motor-driven, Gearhead type.


● 3. Bench lathe


These types of lathe machines are small in size and are used for very small

precision work. Bench lathe machines are mounted on the bench. It has all the

similar parts of engine lathe and speed lathe. Bench lathe machine performs

almost all the operations of engine lathe and speed lathe its only difference

being in the size.


● 4. Toolroom Lathe Machine


Toolroom lathe machine is the same as that of engine lathe but provides a wide

range of speed. The spindle speed range is from very low to quite high speed

up to 2500 rpm. This is equipped beside the other thing, with a chuck, taper

turning attachment, draw in collect attachment, steady and follower rest,

pump for coolant, etc. Toolroom Lathe is costlier as compared to the engine

lathe. It is mainly used in grindings, working on the tool, dies gauges, and in

machining work where accuracy is needed.


● 5. Capstan Lathe and Turret Lathe


These types of lathe machines are used in production work. These lathe

machines are the development of the engine lathe. These machines are

provided by hexagonal turret heads instead of the tailstock. It also consists of

three tool posts.


● 7. Automatic Lathe


In these types of lathe machines, all the work is done automatically. These are

the high-speed heavy-duty, production lathes. In these types of lathe machines

once the tool is set it performs all the operations automatically to finish the job.

Lathe machine performs different operations such as turning, facing, taper

turning, knurling, grooving, parting off, electric turning, thread cutting,

reaming, etc.


● 8. CNC Lathe Machine


These types of lathe machines are operated with a precise set of design

instructions. A CNC (computer numerical control) lathe is a machine tool that

rotates the workpiece around the main spindle, while a cutting tool cuts the

workpiece into a desired shape and size. A simple CNC lathe operates on two

axes with the cutting tool in a fixed position on an 8 to 24 station turret. CNC

lathe ensures consistent product quality and does not require highly skilled

operators to operate the machine. On the other hand, CNC machines are more

expensive than manually operated machines.


● Lathe Machine Operations


The lathe machine operations are classified into three main categories.

Lathe machine operations done either by holding the workpiece between

centers or by a chuck are:–

1. Turning

1. Plain or Straight Turning

2. Rough Turning

3. Turning

4. Taper Turning

5. Eccentric Turning

2. Facing

3. Chamfering

4. Knurling

5. Thread cutting


● History of Lathe Machine


A lathe is an ancient tool, with Weak evidence for its survivor at a

Mycenaean Greek site, dating back as far as the 13th or 14th century BC.

The lathe was very important to the Industrial radiancy. It is known as

the mother of machine tools in industries, as it was the first machine

tool that signs to the invention of other machine tools. The first fully

equipped, all-metal slide rest lathe was invented by Jacques de

Vaucanson around 1751.