Presentation Machine Tool Lathe

7/28/2019 Presentation Machine Tool Lathe

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Machine Tools & Machining

Lathe Machine


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LATHE MACHINING OPERATIONS


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TURNING

Turning is a machining process to produce parts round in shape by

a single point tool on lathes.

The primary motion of cutting in turning is the rotation of the

work-piece, and the secondary motion of cutting is the feed

motion.


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CUTTING CONDITIONS IN TURNING

Cutting speed in turning V in m/s is related to

the rotational speed of the work-piece by the

equation:

V = DN

where D is the diameter of the work-piece,

m; N is the rotational speed of the work-

piece, rev/s.

Rotational speed, not cutting speed, is used to

adjust lathe setting levers.


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CUTTING CONDITIONS IN TURNING

Feed in turning is generally expressed in mm tr-1 (millimetres per

revolution). The turning operation reduces the diameter of the

workpiece from the initial diameter Do to the final diameter Df.

The change in diameter is actually two times depth of cut, d:

2d = Do Df

The volumetric rate of material removal (so-called material

removal rate, mrr) is defined by

mrr = Vfd

When using this equation, care must be exercised to assure that the

units for V are consistent with those for f and d.


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TURNING OF CYLINDRICAL SURFACES

The lathe can be used to reduce the diameter of a part to

a desired dimension. The resulting machined


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TURNING OF FLAT SURFACES

A lathe can be used to create a smooth, flatface very accurately perpendicular to the axis

of a cylindrical part. Tool is fed radially or

axially to create a flat machined surface.


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THREADING

Different possibilities are available to produce

a thread on a lathe. Threads are cut using

lathes by advancing the cutting tool at a feed

exactly equal to the thread pitch. The single-point cutting tool cuts in a helical band, which

is actually a thread.

The tool point must be ground so that it hasthe same profile as the thread to be cut.


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THREADING

Another possibility is to cut threads by means

of a thread die (external threads), or a tap

(internalthreads). These operations are

generally performed manually for smalthread diameters.


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FORM TURNING

Cutting tool has a shape that is imparted to the workpiece by

plunging the tool into the workpiece. In form turning, cutting tool

is complex and expensive but feed is linear and does not require

special machine tools or devices.


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CONTOUR TURNING (PROFILING)

Cutting tool has a simple shape, but the feed motion is complex;

cutting tool is fed along a contour thus creating a contoured shape

on the workpiece. For profiling, special lathes or devices are

required.


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MISCELLANEOUS OPERATIONS

Some other operations, which do not use the single-point

cutting tool can be performed on a lathe, making turning one

of the most versatile machining processes.


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KNURLING

This is not a machining operation at all, because it does not

involve material removal. Instead, it is a metal forming operation

used to produce a regular crosshatched pattern in the work surface.


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Presentation Machine Tool Lathe

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