Lathe Machine: Definition, Parts, Types, Operation, Specification, Advantages, Application

Lathe Machine Definition: A lathe machine is a machine tool that removes the undesired material from a rotating workpiece in the form of chips with the help of a tool that is traversed across the work and can be feed deep into the work.

It is one of the most fundamental and versatile and widely used machine tools all over the world. The lathe is also called as the ‘Mother of all Machines’. Nowadays, Lathe Machine has become a general-purpose machine tool, employed in production and repair work, because it permits a large variety of operations to be performed on it.

Parts of Lathe Machine :

The Lathe Machine consists of the following Main Parts:

Lathe Machine Working Principle:

A Lathe works on the principle of rotating the workpiece and a fixed cutting tool. The workpiece is held between two rigid and strong supports called a centre or in a chuck or in faceplate which revolves. Lathe removes the undesired material from a rotating workpiece in the form of chips with the help of a tool that is transverse across the work and can be fed deep in the work. The main function of the lathe is to remove the metal from a job to give it the required shape and size. The normal cutting operations are performed with the cutting tool fed either parallel or at right angles to the axis of the work. The cutting tool can be fed at an angle relative to the axis of the work for machining tapers and angles.

Products made by Lathe Machine:

A variety of products can be made from the lathe machine and that are Nuts, bolts, piston, ram, pump part, electric motor parts, sleeves, Aircraft parts, gun barrels, candlesticks, train parts, cue sticks, wooden bowls, baseball bat, crankshaft and many more things.

Lathe Machine Types:

Engine Lathe or Center Lathe Machine:

The engine lathe is the most important tool in the Lathe family and by far the most widely used type of Lathe machine.

The operations which can be performed by the Engine Lathe machine are Turning, facing, grooving, knurling, threading, and many more operations that can be performed by it.

Engine lathe consists of headstock, Tailstock, bed, saddle, carriage and other parts.

• The headstock encloses the spindle and motor. It also consists of the gear and pulleys, which are used to change the gear speed and the feed rate.
• The tailstock is provided to facilitate holding the work between centres and permit the use of tools like drills, taps, etc.
• The cutting tool can be fed both in the cross and longitudinal direction with reference to the lathe axis with the help of the feed rod and the lead screw.

The Engine Lathe is available in sizes to handle to 1m diameter jobs and 1 to 4m long.

Turret Lathe Machine:

It is a production machine that is used for the production of products on a large scale. It basically handles heavy-duty workpieces. The distinguishing feature of this type of lathe is that the Tailstock is replaced by a hexagonal Turret.

In this, several tools are set up on a revolving turret to facilitate in performing a large number of operations on a job with minimum wastage of time.

The turret usually accommodates 6 tools for different operations like drilling, countersinking, reaming, tapping, etc, which can be brought into successively working positions by indexing the turret. Turret lathe is basically used for repetitive batch production.

Capstan Lathe Machine:

It is similar to the Turret lathe. Used for the mass production of the light-duty workpiece. It incorporates a capstan slide that moves on the auxiliary slide and can be clamped in any position.

This is best suited for the production of the small parts because of its lightweight and short stroke of capstan slide.

Speed Lathe Machine:

This is the simplest form of the lathe and consists of a simple Headstock, tailstock, and a tool post. Having no gearbox, lead screw, and carriage. Very high speed of the headstock spindle. The speed of the spindle ranges from 1200 to 3600rpm.

Tools are hand-operated. Cone-pulley is the only source provided for speed variation of the spindle.

Speed Lathes are intensively used in woodturning, metal spinning, and polishing operation.

Tool Room lathe Machine:

Tool Room lathe is a modern engine lathe that is equipped with all the necessary accessories for accurate tool room work. It is best suited for the production of small tools, dies, gauges, etc.

It is a geared head driven machine with considerable rage in spindle speed and feeds. Its speed can range from very low to a very high speed of up to 2500 rpm.

Bench Lathe Machine:

Bench Lathe machine is a type of small lathe machine which has all the parts of the engine Lathe and speed lathe. It is mounted on a workbench and is used for doing small precision and light jobs.

Gap bed lathe Machine:

In a gap bed lathe, a gap is provided over the bed near the headstock to handle the job having flanges or some other protruding parts.

Mostly a removable portion is provided in the bed so that when it is not required it can be inserted.

Wheel lathe Machine:

Wheel lathes are a special-purpose lathe machine that is used for finishing the journals and turning the tread on locomotive wheels.

T- Lathe machine Machine:

T- Lathe machine is a type of machine which has a T shaped bed and is used in the aerospace industry for the machining of the rotors of the jet engine.

Automatic Lathe Machine:

As the name suggests automatic Lathe machine is a machine in which the complete work and the job handling movements required for the completion of the job are done automatically.

They are heavy-duty, mass production, and a high-speed machine.

CNC Lathe Machine:

Computer Numeric Control (CNC) is the most advanced form of the lathe machine. CNC lathe machine produces the most accurate products as compared to the other type of lathe machine.

In this machine, programs are being fed to the computer system which controls the overall working of the lathe.

It is used for large scale production. Semi-skilled workers are required for the operation of this machine.

Different Operation Performed on Lathe Machine:

The following different types of Lathe Machine Operation are:

Let’s start discussing them one by one:

Turning Operation:

Turning is the most common operation performed on the lathe. Turning is a machining operation in which the diameter of the workpiece is being reduced by removing the excess material from the outer diameter of the job (workpiece) which is mostly cylindrical or conical in shape.

Turning operation results in a good surface finish of the metal.

The various type of turning operation are:

Tapered Turning Operation:

Tapered Turning is a machining process in which the cylindrical jobs are being machined to produce a conical surface. In taper Turning the tapered component will be produced.

The various methods used for Taper Turning are:

1. Compound Rest Method
2. Tailstock Method.
3. Taper Turning Attachment method
4. Form tool Method.

Let’s discuss each method in brief:

Taper Turning Attachment Method:

In the taper turning attachment method, the slideways are tilted by an angle equal to the taper angle of the component so that the saddle is automatically tilted and when the saddle is moving on the slideways it produces a tapered component.

FEATURES:

1. It can be used for both internal, external operations.
2. Up to 0.1degree accuracy can be produced.
3. Maximum taper angle which can be produced is 8 degree.
4. The maximum taper length of the component in one sitting is 235mm.

Compound Rest Method:

In the compound Rest Method the compound rest is swivelled by an angle equal to the required taper angle on the component. Any taper angle can be produced by this method and both internal and external taper turning operations can be performed by this method.

Tailstock method:

The method is used for producing only external tapers. In this method, the tailstock is moved from its middle position to one side of the bed, which makes the workpiece tilted with respect to the lathe axis and feed.

Thus, when the tool moves it cuts the workpiece at an angle to the axis creating a taper.

Form Tool method:

The form tool method is used for producing external tapers only. The form tool method is a type of method in which the shape of the tool is the same as that of the shape of the component to be produced. Whatever the angle on the tool that can be produced on the component.

Shoulder Turning Operation:

Shoulder Turning is used in the case where several diameters are to be turned on the workpiece. The surface forming the step from one diameter to the other is called the shoulder.

There are four types of shoulder:

1. Square
2. Bevelled
3. Radius and
4. Undercut.

A right-cut tool is used to make the square shoulder.

Facing operation:

Facing is a process in which the end of the workpiece is being machined by the tool which is at a right angle to the axis of the rotation of the workpiece.

Facing is frequently the first operation performed in the production of the workpiece and often the last. We can relate it to the phrase” ending-up”, which will help us in remembering its sequence.

Thread cutting operation:

Thread cutting is a type of operation in which the threads are being cut on the internal and the outer surface of the workpiece as per the requirement.

In the thread cutting operation, only the automatic feed is given.

The automatic feed required for the thread cutting operation is given by using a lead screw and the feed gearbox.

The feed of the lead screw has to be changed in order to get the different pitch of thread on the job.

JOB SPEED: Job speed during threading is up to 1/4^th of the job speed during turning.

Parting Operation:

Parting is an operation in which the deep groves are being made on the parent material to remove the specific portion from the parent material resulting in dividing the workpiece into two or more parts.

Chamfering Operation:

Chamfering is the operation of beveling the extreme end of a workpiece. Chamfering is provided for:

1. Better look.
2. To enable the nut to pass freely on the threaded workpiece.
3. Remove burrs and
4. Protect the end of the workpiece from being damaged.

Chamfering is done usually after knurling, thread cutting, etc…

Knurling Operation:

The process of making the surface of the workpiece rough by embossing (impressing) a diamond-shaped regular pattern on the surface by making use of a knurling tool is called a knurling operation.

Knurling is done at a lower speed and plenty of oil is used. Knurling provides an effective gripping surface on a workpiece to prevent it from slipping when operated with a hand.

Drilling Operation:

Drilling operation is a type of machining operation which is used to remove the material from the workpiece by making use of a drill bit, which is held stationary in the Tailstock. Finally creating a hole in the workpiece.

Drill bits are generally made up of high-speed steels and carbon steels.

Boring Operation:

Boring is an internal turning operation used for enlarging the existing holes by some amount.

It can further be divided as:

Counter boring:

Contour boring is an internal turning operation used for enlarging the end of the holes.

Countersinking:

Counter Sinking is the operation of the conical enlargement of the end of the hole. It requires a large size drill bit then that required for the hole.

Reaming Operation:

It is a machining process that is done after drilling to make internal holes of a very accurate diameter. This operation helps to remove a very small amount of material from the holes which are already drilled.

Lathe Machine Operation Video:

Now we will study Specification of Lathe Machine,

Lathe Machine Specification:

a) The length between the two centers:

It is the measure of the maximum length of the workpiece that can be fixed between the lathe centre.

b) Height of the centre:

The distance between the lathe axis and the lathe bed is called the height of the centre.

c) Swing Diameter over the bed:

It is the maximum diameter of the workpiece that can we turned on a lathe without hitting the lathe bed.

d) Maximum bar diameter:

It is the maximum diameter of the workpiece that can be passed through the hole in the headstock.

Other factors for the lathe specification are:

• Tailstock sleeve travel.
• Metric thread pitches.
• Leadscrew Pitch.
• Motor horsepower and RPM.
• Shipping dimension: (length x width x height x weight).

Application of Lathe Machine:

• Textile
• Power Generation
• Defense
• Medical
• Plastic
• Aerospace
• Automotive
• Automobile industries.

Advantages of the Lathe machine:

1. High-Quality Products:  Lathe machine, especially the CNC Lathe machine, produce final products with high quality.

2. High Speed: The machining in the lathe can be done at a very high speed especially in automatic and CNC lathe machines.

3. Saves time: Lathe machine because of its extensive high speed and high accuracy saves a lot of time, resulting in the increased production.

4. Saves Money: Lathe machine helps in reducing the cost of machining because fewer operators are required for machining.

Disadvantages of Lathe Machine:

This is all about the Definition, Introduction, Parts, Types, Application, Advantages, Disadvantages, and [Notes with PDF] of Lathe Machine.