“In pursuit of global competitiveness”

Government College Of Engineering,Aurangabad.

TurningCreated BY:- NIKHIL PAKWANNE

TURNING

Turning is the operation to remove material from the outside diameter of a workpiece to obtain a finished surface. The finished surface may be of continuous diameter, stepped,tapered or contoured .

TYPES OF TURNING

1. Straight turning

2. Rough turning

3. Finish turning

4. Shoulder turning

Straight Turning• The work is turned straight when it is

made to rotate about the lathe axis and tool is fed parallel to the lathe axis.the straight turning produces a cyllindrical surface by removing excess metal from the workpiece.

ROUGH TURNING• The rough turning is the process of

removal of excess material from the workpiece in a minimum time by applying high rate of feed and heavy depth of cut.

• The roughing cut should be so made that the machine, the tool and the workpiece, can bear the load and it does not make too rough a surface and spoil the centres.

FINISH TURNING• The finish turning operations requires high

cutting speed, small feed and a very small depth of cut to generate a smooth surface.

• The finish turning tool having sharp cutting edge is held on the tool post for this purpose.

• The depth of cut ranges from 0.5-1mm and feed from 0.1-0.3mmper revolution of the workpiece.

Rough turning outside the bowl.

SHOULDER TURNING• When a workpiece having different diameter

is turned, the surface forming the step from 1diameter to other is called shoulder and the machining this part of workpiece is called shoulder turning.

• There are four kinds of shoulder:-1. Square shoulder2. Angular shoulder3. Radius shoulder4. Undercut shoulder

Tapers & Taper turning

• A taper may be defined as a uniform increase or decrease in diameter of a piece of work measured along its length.

• Taper turning means to produce a conical surface by gradual reduction in diameter from cyllindrical workpiece.

• This tappering of a part has wide application in the construction of machines.

ECCENTRIC TURNING

• It is a cyllindrical workpiece has to separate axis of rotation. One being out of centre to the other,the workpiece is turned eccentric and turning of different surfaces of the workpieces is known as eccentric turning.

• Crank shaft turning in lathe

General shape of eccecntric turning

Dynamics Of Turning• The relative forces in a turning operation

are important in the design of machine tools. The machine tool and its components must be able to withstand these forces without causing significant deflections, vibrations, or chatter during the operation. There are three principal forces during a turning process: cutting force, thrust force and radial force.

ADVANTAGES OF TURNING

1. All types of material can be turned.

2. Most versatial machine producing external and internal circular profiles and flat surfaces.

3. Low to link cost

4. Large components can be turning.

LIMITATIONS OF TURNING

1. Requires skilled labour

2. Low production rate

3. Close tolerances and find finish cannot be achieved.

REFERENCE

• WORKSHOP TECHNOLOGY VOL-П

S.K. HAJRA CHOUDHARY

• ELEMENTS OF MECHANICAL ENGG.

K.B.BOKANKAR

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