Turning Bahan Kuliah

8/3/2019 Turning Bahan Kuliah

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Turning & Boring

General Manufacturing Processes Engr.-20.2710

Instructor - Sam Chiappone


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ChiapponeRensselaer Polytechnic Institute

Turning & Boring

Turning is the process of machining external

cylindrical and conical surfaces. The process uses

a machine tool called a lathe. Boring is the

process of enlarging an existing hole or internalcylindrical surface. This can be accomplished on

a lathe or a machine tool specifically designed for

the process; such as a horizontal boring machine.


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Turning & Boring

Some of the main reasons for utilizing this process

include:

Concentricity between features

External thread to shaft diameter Part tolerance

Surface finish

Part features

Turning typically involves roughing procedures

followed by a finishing operation.


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Process Calculations

Rpm calculation

RPM

CS


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Process Calculations

Feed is typically a given distance per revolution.

This value is dependent on the operation, depth of

cut, cutting speed, tool material, surface finish----

etc. Units are--- in. per rev (in./rev)


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Turning Operations

Turning operations performed on a lathe include:

Straight turning

Taper turning

End facing Shoulder facing


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Turning Operations

Facing

Grooving

Form turning

Parting-off


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Turning Operations

Threading

Knurling

Drilling

Reaming Milling-CNC

turning centers


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Lathe Components

Bed

foundation of the lathe

Headstock

Mounted on the ways

Consists of the:

Hollow spindle

Bearings

Transmission gears


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Lathe Components

Spindle

Carries the workholders

Hole to accept long work or bar

stock

Tailstock

Lower portion of casting fits inner

ways

Can slide longitudinally Locks at desired location

Tailstock quill


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Lathe Components

Carriage

Along with the apronprovides the base for mounting

and moving cutting tools

Cross slide Mounted to the carriage and provides movement for

facing and cut-off operations.

Compound rest

Mounted to the cross slide. Can rotate for angle cuts.

This is the component that holds the tool post for

cutting tools.


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Lathe Components

Feed rod

Provides forward and reverse motion for carriage and

cross slide.

Lead screw Used for threading purposes. Engages with the half-nut

to provide correct feed specific lead of thread.


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Machine Classification

Size designation

Swing - maximum diameter that can be rotated on the

lathe

2xs distance from spindle center line to ways Maximum distance between centers


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Types of Lathes

Speed

Simple construction of a head stock and tail stock with

a tool post. Used for wood turning, metal polishing, or

metal spinning. Engine

Most frequently used lathe

Heavy duty

power drive for most tool movements

Size range 12x24 to 24x48 - can be larger


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Types of Lathes

CNC

Computer controlled

Wide variety of process capability

multiple axis Indexing and contouring head

On- line and off- line programming available


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Types of Lathes

Toolroom

Greater accuracy

More versatility

Wider range of speeds and feeds

Turret

Hex turret replaces tailstock

Multiple tools set to machine part

High production rates

Still may require some operator skill


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Types of Lathes

Automatic

Similar to turret

Eliminate operator control of machine

Capable of simultaneous cuts Can be a cam controlled mechanism

Can be single spindle or multiple spindle

Tracer

Hydraulic attachment used to copy the shape of a part

from a master.


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Types of Lathes

1

2

3


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Cutting Tools for Lathes

External

Right hand turning

Left hand turning

Round nose turning Cut-off

Left hand facing


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Cutting tools for Lathes

External (cont) Broad nose finishing

Right hand facing

Threading

Form

Internal

Boring

Threading

Grooving

Form


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Workholding on a Lathe

Between centers

Live-tailstock

Dead-headstock

Face plate Drive dog


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Chuck

3,4, or 6 jaw

Soft jaws


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Collect system


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Others

Face driver system

Sub-spindle system

Turning Bahan Kuliah

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