A turret lathe is a semi-automatic lathe machine that is used for repetitive production of lathe parts.
It is advance from the lathe machine produced earlier as it has a hexagonal turret.
Hexagonal turret is an indexable tool holder which can hold six tools at a time. With the help of hexagonal turret, multiple cutting operations can be performed each with different cutting tool in rapid succession without the need to replace or install and uninstall the tool in the lathe machine.
In turret lathe, the tool can be switched automatically resulting in faster and more efficient production processes. The turret lathe can change to a different cutting tool in a few seconds but in a traditional lathe, it can take minutes for a human worker to manually change the cutting tool.
When many operations are to be performed and the production has to be increased, the turret lathe is used.
Parts Of Turret Lathe:
There are two legs present in Turret Lathe. The entire lathe machine of turret lathe is present over these two legs. These legs are used to carry the total load of the machine. These legs are bolted on the floor to prevent any vibrations in the machine.
Bed is present over two legs. This bed is made up of cast iron as it has to withstand a lot of load and it must be shock absorbing. This bed is made through casting.
3) Head Stock:
All the gearing mechanism or driving mechanism of this lathe machine is present inside the headstock. It has gears, pulleys, or motor is present based on the driving mechanism used in the lathe.
It is the part of the turret lathe which rotates the chuck. It is present in the head stock and rotates when engaged with gears present inside the head stock.
Chuck is used to hold and rotate the workpiece. The chuck is bolted to the spindle and rotates when the spindle rotates.
This chuck can be of two types 3 jaw chuck or 4 jaw chuck. 3 jaw chuck is also known as universal chuck.
3 jaw chuck is known as universal chuck because as we insert a single tool in the tool slot of the 3 jaw chuck then all 3 jaws of this chuck start moving together but in 4 jaw chuck, we have to insert 4 tools in slots to move the 4 jaws together.
3 jaw chuck is used to hold cylindrical jobs and 4 jaw chuck can be used to hold square, hexagonal and irregular shaped jobs.
6) Driving Clutch:
It is used to engage and disengage the connection between the gears and the spindle. At starting the gears and spindle are disengaged but when motion is needed, the gears and the spindle can be engaged using driving clutch.
Guideways are the predefined slotted path over which the carriage and saddle moves.
7) Feed Rod:
Feed Rod provides precise longitudinal movement to the carriage. The carriage move over the feed rod and the guideways. It is named as feed rod because it provides movement to the carriage.
Saddle can move left and right over the guidewats. There are two saddles present in this turret lathe. One saddle is to carry the tool post and another saddle is to carry the hexagonal turret.
9) Cross Slide:
Cross Slide can move across the bed perpendicular to the direction of the movement of saddle. This cross slide is present between the tool post and saddle in the turret lathe.
10) Tool Post:
The tool post is used to hold the tool in the turret lathe machine. It is particularly used to hold single point cutting tool. This tool post can move horizontally in the left or right directions. It can also move across the bed using the cross-slide. It can moved using handwheel or can be moved automatically.
8) Clutch Lever:
The Clutch lever is present in the headstock. It is used to engage and disengage the driving mechanism with the spindle. This hexagonal turret is present over the saddle which can move
9) Hexagonal Turret:
A hexagonal turret is used to hold different tools for different operations of the workpiece. It is called a hexagonal turret because 6 tools can be hold simultaneously in it. It is directly mounted on the saddle in this lathe. This hexagonal turret is also present in the capstan lathe but a ram is present between the saddle and the hexagonal turret.
Unlike the simple lathe machine, this turret lathe does not have tailstock.
Working Of Turret Lathe:
At first, workpiece which is to be changed into a desired shape and size is held in the chucks. These chucks are operated hydraulically or pneumatically.
After that, all the tools are placed in the respective holes of the hexagonal turret.
Then the chucks are rotated by rotating the spindle. As the chuck rotates, the workpiece attached to the chucks also rotates and the hexagonal turret head is moved towards the rotating workpiece by moving the saddle.
This hexagonal tool head can rotate and by rotating it, the required tool is faced towards the workpiece.
After the required tool faces the workpiece, the tool is brought into contact with the workpiece, and the required operation is performed.
After one operation is completed using a tool, another tool is brought forward to perform different operations by rotating the hexagonal turret head.
In manual turret lathe, the required tool is directly brought in use by the rotation of the turret by the operator but in automatic turret lathe,
the turret head is brought to its initial position after the completion of each operation and the tools are indexed automatically.
Types Of Turret Lathe:
Based on orientation, turret lathes are divided into two types:
1) Horizontal turret lathe – In horizontal turret lathe the orientation of the hexagonal turret and the workpiece is horizontal.
2) Vertical turret Lathe – In vertical turret lathe, the hexagonal turret and the workpiece has a vertical orientation. The workpiece is kept in the horizontal lathe table and the axis of the workpiece and the chuck is vertically perpendicular to the lathe table.
Based on the method of control, turret lathes are divided into 4 types:
1) Manual Turret Lathe:
Manual turret lathe is the first turret lathe in order of historical appearance. The term “turret lathe” without specifying type is understood to refer to this type. This type of turret lathe requires some amount of manual labour for its operation.
2) Automatic Turret Lathe (Mechanically):
After the manual turret lathe machine, the automatic turret machine was developed which further reduced the duties of the operator and also increased productivity. These turret lathes can execute many part-cutting cycles without human intervention. These turret lathes automate the sliding and indexing of the turret and opening and closing of the chuck using cams.
Small and medium automatic turret lathes are known as screw machines or automatic screw machines and the large automatic turret lathe are called automatic chucking lathes or automatic chuckers,
3) NC and CNC Turret Lathes:
NC stands for Numerical Control and CNC stands for Computer Numerical Control.
The numerical control lathes automate using electronic based automation and computer numerical control sutomate using computer.
These type of lathes have a feature to automatically select the tools of a turret.
This nc and cnc automated turret lathe replaced the mechanically automated turret lathe and manual turret lathe but not completely.
Advantages Of Turret Lathe:
1) Large number of tools can used without the need to replace the tool after each operation.
2) Increase in production rate.
3) Decrease in labour cost as less number of skilled labours are required.
4) In this lathe, we can obtain different ranges of speed.