General Purpose Machine Tools_Spal.ppt

7/25/2019 General Purpose Machine Tools_Spal.ppt

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General Purpose Machine Tools

1. General classification of machine tools

Conventional or traditional machine tools like

Lathes, Milling machines, etc. are used more widely

for faster material removal by shearing or brittlefracturing.

Non-conventional or non-traditional machine

tools: like EDM, ECM, UM, etc. which remove

material from e!otic materials slowly by electro"

#hysical, electro"chemical #rocesses.

Modern numerical and computer controlled

machinetools$ Like C%C lathe, C%C milling


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General Purpose Machine Tools

&he basic machine tools which are commonly used for general#ur#oses are$

1. Lathes

2. Drillin machines

!. "hapin machines

#. Plannin machines

$. "lottin machines

%. Millin machines

&. 'orin machines

(. )o**in machines

+. Gear shapin machines

1,. 'roachin machines

11. Grindin machine


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Classification f Lathes

'a( )ccording to configuration

*ori+ontal "Most common for ergonomic conveniences

ertical " -ccu#ies less floor s#ace, only some large lathesare of this ty#e.

'b( )ccording to #ur#ose of use eneral #ur#ose

ery versatile where almost all #ossible ty#es of o#erations arecarried out on wide ranges of si+e, sha#e and materials of /obs0e!am#le$ centre lathesingle #ur#ose$ -nly one 'occasionally two( ty#e of o#erationis done on limited ranges of si+e and material of /obs0 e!am#le1 facing lathe, roll turning lathe etc.

#ecial #ur#ose " 2here a definite number and ty#e ofo#erations are done re#eatedly over long time on a s#ecificty#e of blank0 e!am#le$ gear blank machining lathe etc.


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'c( )ccording to si+e or ca#acity

mall 'low duty( " 3n such light duty lathes 'u#to 4.4 k2(, onlysmall and medium si+e /obs of generally soft and easilymachinable materials are machined

Medium 'medium duty( " &hese lathes of #ower nearly u#to 44k2 are most versatile and commonly used

Large 'heavy duty(

Mini or micro lathe " &hese are tiny table"to# lathes used fore!tremely small si+e /obs and #recision work0 e!am#le $ swissty#e automatic lathe


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'd( )ccording to degree of automation

%on"automatic " )lmost all the handling o#erations are donemanually0 e!am#le$ centre lathes

emi"automatic " %early half of the handling o#erations,irres#ective of the #rocessing o#erations, are doneautomatically and rest manually0 e!am#le$ ca#stan lathe, turretlathe, co#ying lathe relieving lathe etc.

)utomatic " )lmost all the handling o#erations 'and obviouslyall the #rocessing o#erations( are done automatically0 e!am#le1 single s#indle automat 'automatic lathe(, swiss ty#e automaticlathe, etc.

e( )ccording to ty#e of automation 5i!ed automation " Conventional0 e!am#le 1 single s#indleautomat, swiss ty#e automatic lathe etc.

5le!ible automation " Modern0 e!am#le C%C lathe, turningcentre etc.


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'f( )ccording to configuration of the /obs being handled

6ar ty#e " lender rod like /obs being held in collets Chucking ty#e " Disc ty#e /obs being held in chucks

'g( )ccording to #recision

-rdinary

7recision 'lathes( " &hese so#histicated lathes meant for highaccuracy and finish and are relatively more e!#ensive.

'h( )ccording to number of s#indles

ingle s#indle "Common

Multis#indle '8, 9, : or ; s#indles(uch uncommon lathes are suitably used for fast and mass#roduction of small si+e and sim#le sha#ed /obs.


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i ti " t 0 d i P i i l


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inematics "/stem 0nd orin Principle

f Lathes


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Machinin perations 3suall/ Done 4n Centre Lathes 5acing Centering . combining longitudinal feed and cross feed, if feasible.

6oring 'internal turning(0 straight and ta#er 5orming0 e!ternal and internal Cutting helical threads0 e!ternal and internal 7arting off ?nurling


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Machinin perations 3suall/ Done 4n Centre Lathes

&urning

5acing


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rooving

7arting


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6oring


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'asic purposes of use of drillin machines

Drilling machines are generally or mainly used tooriginate throuh or *lindstraight cylindrical holes insolid rigid bodies and@or enlarge 'coa!ially( e!isting'#re"machined( holes $

1 of different diameter

1 of varying length de#ending u#on the reAuirement

and the diameter of the drill1 in different materials e!ce#ting very hard or very

soft materials like rubber, #olythene etc.


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Classification of drilling machines

05 General purpose drillin machines of common

use

Ta*le top small sensitive

drillin machine: &hese small

ca#acity 'B .> k2( u#right

'vertical( single s#indle drillingmachines are mounted 'bolted(

on rigid table and manually

o#erated using usually small si+e

'B 4 mm( drills.


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05 General purpose drillin machines

Pillar drillin machine :&hese

drilling machines are Auite similar

to the table to# drilling machines

but of little larger si+e and higherca#acity '.>> 4.4 k2( and are

grouted on the floor 'foundation(.


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Column drillin machine:&hese bo! sha#ed column ty#e

drilling machines are much more

strong, rigid and #owerful than

the #illar drills. 3n column drills

the feed gear bo! enables

automatic and #ower feed of the

rotating drill at different feed rates

as desired.


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6adial drillin machine:

&his usually large drilling

machine #ossesses a

radial arm which along withthe drilling head can swing

and move vertically u# and

down. &he radial, vertical

and swing movement of

the drilling head enableslocating the drill s#indle at

any #oint within a very

large s#ace reAuired by

large and odd sha#ed /obs.


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CNC column drillin machine: 3nthese versatile and fle!ibly automatic

drilling machine having bo!"column

ty#e rigid structure the work table

movements and s#indle rotation are

#rogrammed and accom#lished by

Com#uter %umerical Control 'C%C(.

)and drills$ hand drill is a #ortable drilling

device which is mostly held in hand and

used at the locations where holes have to

be drilled.


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'5 General purpose drillin machines 7ith more

specific use

Gan drillin machine: &his is

almost single #ur#ose and more

#roductive machine a number '8

to :( of s#indles with drills 'ofsame or different si+e( in a row

are made to #roduce number of

holes #rogressively or

simultaneously


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specific use

Turret 8t/pe5 drillin machine:&urret drilling machines are

structurally rigid column ty#e but are

more #roductive like gang drill by

having a #entagon or he!agon turret.


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specific use

Multispindle drillin machine:

3n these high #roduction machine

tools a large number of drills work

simultaneously on a blank

through a /ig s#ecially made for

the #articular /ob. &he entire

drilling head works re#eatedly

using the same /ig for batch or lot

#roduction of a #articular /ob.


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specific use

Deep hole drillin machine:ery dee# holes of L@D ratio : to even

=

Machinin Parameters:

Cuttin motion

9eed motion

3n drilling machines, generally both the cutting motion and feed

motion are im#arted to the drill.


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Milling machines


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Classification of Milling machines

0ccordin to confiuration and motion of the 7or-holdin ta*le

nee t/pe: small and medium duty

machines the table with the

/ob@work travels over the bed

'guides( in hori+ontal 'F( andtransverse 'G( directions and the

bed with the table and /ob on it

moves vertically 'H( u# and down.


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'ed t/pe : Usually of

larger si+e and ca#acity0

the vertical feed is given to

the milling head instead ofthe knee ty#e bed


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Planer t/pe : &hese heavy

duty large machines, called

#lano"miller, look like

#laning machine where thesingle #oint tools are

re#laced by one or a

number of milling heads0

generally used for

machining a number of

longitudinal flat surfacessimultaneously.


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Milling machines

6otar/ ta*le t/pe : &his

high #roduction milling

machines #ossess one

large rotary work"table andone or two vertical s#indles.

the #ositions of the /ob's(

and the milling head are

ad/usted according to the

si+e and sha#e of the /ob.


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Classification of Milling machines0ccordin to the orientation of the spindle8s5.

)oriontal spindle t/pe$


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;ertical spindle t/pe$


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3niversal head millin

machine$

General Purpose Machine Tools_Spal.ppt

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