an introduction to cnc machines ppt

7/24/2019 An introduction to CNC Machines PPT

1/20

Introduction to Computer Numeri

Controlled(CNC) Machines and i

Advantages

Subm

Bulon C

Scholar n

Cad cam a

Submitted to:Mr. Pannalal ChoudhuryAssociate Professor


2/20

Introduction: Computer Numerical Co(CNC) Machine Computer Numerical Control (CNC machine is one in

the functions and motions of a machine tool are contr"# means mini or microcomputer$

All the cuttin% processes that are to "e carried out anthe &nal dimensions are fed into the computer 'ia thepro%ram$ he computer thus )no!s !hat e*actl# is to

done and carries out all the cuttin% processes$ CNC m!or)s li)e the +o"ot, !hich has to "e fed !ith the proand it follo!s all #our instructions$

he computer translated the pro%ram into the appropelectrical si%nals for input to motors that run the mac

N S.C/A+,ASSA


3/20

History: 155 -John Parsons and US Air Force de&ne a need to de'el

machine tool capa"le of machinin% comple* and close tolerance

parts !ith the same ualit# time after time (repeata"ilit#$hicthe introduction Numerical Control(NC machines !hich !as conand operate usin% a punched tape$

Standardi4ation of G code in the earl# 06s$

10 - Direct Numerical Control (DNC). his eliminates pappunch pro%rams and allo!s pro%rammers to send &les directl# ttools$

1806s - 7raphics "ased CA9CA s#stems introduced$

odern NC machine has a computer on "oard! Computer NumControl(CNC)$ he# can run unattended at o'er 20,000 r$p$m speed !ith a feed rate of o'er 00 i$p$m and an accurac# of $00

N S.C/A+,ASSA


4/20

Some of common type of CNC machi

CNC "athe MachineCNC Millin# Machine

CNC $rillin# Machine

CNC Grindin# MachineCNC "aer Cutter

%$ Printer

&'ample o CNMachineN S.C/A+,ASSA


5/20

Eamples of CNC Machines:

CNC Millin# Machine HS CNC *urnin# Machine HN S.C/A+,ASSA


6/20

Salient +eature o CNC Machi

Machine Control ,nit (MC,) i a microcomputer -here -e #ie thecommand and e'ecute the command into action by the machin

$iplay ,nit diplay all the neceary inormation uch a the pipoition! depth o cut etc.

/nput $eice throu#h -hich can enter pro#ram directly and run tthe #ien operation.

*ool can operate in 012 a'e thu makin# it eaier to machine com#eometrical hape.

Moement i controlled by motor (actuator) -hich proide preci

tool and the table in the re3uired direction.

+eedback i proided by enor (tranducer) -hich proide thethe poition o the tool and the -ork piece.

*ool ma#azine can hold a lar#e number o tool are ued to chanautomatically.

CNC machine can -ork automatically or hour -ithout any upe

N S.C/A+,ASSA


7/20

Baic &lement o CNC mach

a$ nput e'ice"$ achine Control nitc$ achine oold$ ri'in% S#steme$ ;eed"ac) e'icesf$ ispla# nit

&'ample o a $ipN S.C/A+,ASSA


8/20

4orkin# principle o a CNMachine

Block $ia#ramN S.C/A+,ASSA


9/20

Baic CNC 'i o Motion

Standard Millin# CoordiN S.C/A+,ASSA


10/20

*hree Baic Cate#orie o MotionSytem in CNC

Point to Point 1 No contourin# capability

Strai#ht cut control 1 one a'i motion at a time i controlled or mac

Contourin# 1 multiple a'i5 controlled imultaneouly

N S.C/A+,ASSA


11/20

Ho- CNC machine perorm an operatiothe -ork piece6

*o perorm an operation -e hae to -ri

a Part Program -hich can be preparedmanually(#enerally or mall pro#ram)automatically prepared(or comple'

#eometrical hape) -ith the help oot-are packa#e.

N S.C/A+,ASSA


12/20

4hat i a Part Pro#ram

an introduction to cnc machines ppt

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