cnc chapter 1 lecture

Laboratory for Manufacturing Systems and Automation

COMPUTER NUMERICAL CONTROL COMPUTER NUMERICAL CONTROL

OF MACHINE TOOLSOF MACHINE TOOLS

COMPUTER NUMERICAL CONTROL COMPUTER NUMERICAL CONTROL

OF MACHINE TOOLSOF MACHINE TOOLS

Laboratory for Manufacturing Systems and Automation Laboratory for Manufacturing Systems and Automation Dr. Dimitris MourtzisDr. Dimitris Mourtzis

Laboratory for Manufacturing Systems and Automation

Department of Mechanical Engineering and Aeronautics

University of Patras, Greece

Chapter 1: Chapter 1:

An Introduction to Numerical Control An Introduction to Numerical Control


An Introduction to Numerical Control An Introduction to Numerical Control

MachineryMachinery

Objectives of Chapter 1Objectives of Chapter 1

�� DescribeDescribe thethe differencedifference betweenbetween directdirect andand distributivedistributive

NumericalNumerical ControlControl (NC)(NC)

�� DescribeDescribe thethe differencedifference betweenbetween aa numericalnumerical controlcontrol tapetape

machinemachine andand aa ComputerComputer NumericalNumerical ControlControl (CNC)(CNC) machinemachine

DescribeDescribe fourfour waysways thatthat programsprograms cancan bebe enteredentered intointo aa

�� DescribeDescribe thethe differencedifference betweenbetween directdirect andand distributivedistributive

NumericalNumerical ControlControl (NC)(NC)

�� DescribeDescribe thethe differencedifference betweenbetween aa numericalnumerical controlcontrol tapetape

machinemachine andand aa ComputerComputer NumericalNumerical ControlControl (CNC)(CNC) machinemachine

DescribeDescribe fourfour waysways thatthat programsprograms cancan bebe enteredentered intointo aa


�� DescribeDescribe fourfour waysways thatthat programsprograms cancan bebe enteredentered intointo aa

computercomputer numericalnumerical controllercontroller

�� ExplainExplain twotwo tapetape codecode formatsformats inin useuse withwith CNCCNC machinerymachinery

�� GiveGive thethe majormajor objectivesobjectives ofof NumericalNumerical ControlControl

�� DescribeDescribe fourfour waysways thatthat programsprograms cancan bebe enteredentered intointo aa

computercomputer numericalnumerical controllercontroller

�� ExplainExplain twotwo tapetape codecode formatsformats inin useuse withwith CNCCNC machinerymachinery

�� GiveGive thethe majormajor objectivesobjectives ofof NumericalNumerical ControlControl


�� NumericalNumerical ControlControl (NC)(NC) helpshelps solvesolve thethe problemproblem ofof makingmaking

ManufacturingManufacturing SystemsSystems (MFG)(MFG) moremore flexibleflexible

“A Numerical Control machine is a machine positioned “A Numerical Control machine is a machine positioned

automatically along a automatically along a prepre--programmedprogrammed path by means of path by means of

codedcoded instructions”instructions”

�� NumericalNumerical ControlControl (NC)(NC) helpshelps solvesolve thethe problemproblem ofof makingmaking

ManufacturingManufacturing SystemsSystems (MFG)(MFG) moremore flexibleflexible

“A Numerical Control machine is a machine positioned “A Numerical Control machine is a machine positioned

automatically along a automatically along a prepre--programmedprogrammed path by means of path by means of

codedcoded instructions”instructions”


�� ManualManual PartPart ProgrammingProgramming:: ManualManual programmingprogramming ofof thethe

machinesmachines

�� ComputerComputer AidedAided ProgrammingProgramming (CAP)(CAP):: ProgrammingProgramming donedone

byby aa computercomputer

�� ManualManual DataData InputInput (MDI)(MDI):: AA manualmanual programprogram isis enteredentered intointo

thethe machine’smachine’s controllercontroller viavia itsits ownown keyboardkeyboard

�� ManualManual PartPart ProgrammingProgramming:: ManualManual programmingprogramming ofof thethe

machinesmachines

�� ComputerComputer AidedAided ProgrammingProgramming (CAP)(CAP):: ProgrammingProgramming donedone

byby aa computercomputer

�� ManualManual DataData InputInput (MDI)(MDI):: AA manualmanual programprogram isis enteredentered intointo

thethe machine’smachine’s controllercontroller viavia itsits ownown keyboardkeyboard


�� ComputerComputer isis usedused asas thethe ControlControl UnitUnit (CU)(CU) ofof thethe modernmodern

NumericalNumerical ControlControl machinerymachinery

�� ComputerComputer replacedreplaced thethe TapeTape ReaderReader foundfound onon earlierearlier NCNC

machinesmachines

�� ProgramProgram isis loadedloaded intointo andand executedexecuted fromfrom thethe machine’smachine’s

computercomputer

�� ComputerComputer isis usedused asas thethe ControlControl UnitUnit (CU)(CU) ofof thethe modernmodern

NumericalNumerical ControlControl machinerymachinery

�� ComputerComputer replacedreplaced thethe TapeTape ReaderReader foundfound onon earlierearlier NCNC

machinesmachines

�� ProgramProgram isis loadedloaded intointo andand executedexecuted fromfrom thethe machine’smachine’s

computercomputer


�� ComputerComputer NumericalNumerical ControlControl (CNC)(CNC) machinesmachines areare thethe NCNC

machinesmachines ofof todaytoday

�� FOCUSFOCUS onon:: MDIMDI programmingprogramming ofof CNCCNC machinerymachinery

�� ComputerComputer NumericalNumerical ControlControl (CNC)(CNC) machinesmachines areare thethe NCNC

machinesmachines ofof todaytoday

�� FOCUSFOCUS onon:: MDIMDI programmingprogramming ofof CNCCNC machinerymachinery

The History of NCThe History of NC

�� 19471947:: JJ.. ParsonsParsons (Parsons(Parsons Corporation)Corporation) beganbegan

experimentingexperimenting forfor usingusing 33--axisaxis curvaturecurvature datadata toto controlcontrol

machinemachine tooltool motionmotion forfor thethe productionproduction ofof aircraftaircraft

componentscomponents

�� 19491949:: ParsonsParsons awardedawarded aa USUS AirAir ForceForce contractcontract toto buildbuild thethe

firstfirst NCNC machinemachine

�� 19471947:: JJ.. ParsonsParsons (Parsons(Parsons Corporation)Corporation) beganbegan

experimentingexperimenting forfor usingusing 33--axisaxis curvaturecurvature datadata toto controlcontrol

machinemachine tooltool motionmotion forfor thethe productionproduction ofof aircraftaircraft

componentscomponents

�� 19491949:: ParsonsParsons awardedawarded aa USUS AirAir ForceForce contractcontract toto buildbuild thethe

firstfirst NCNC machinemachine


�� 19511951:: MITMIT waswas involvedinvolved inin thethe projectproject

�� 19521952:: NCNC achievedachieved whenwhen MITMIT demonstrateddemonstrated thatthat

simultaneoussimultaneous 33--axisaxis movementsmovements werewere possiblepossible usingusing aa

laboratorylaboratory--buildbuild controllercontroller andand aa CincinnatiCincinnati HYDROTELHYDROTEL

verticalvertical spindlespindle

�� 19551955:: afterafter refinementsrefinements NCNC becomebecome availableavailable toto industryindustry

�� 19511951:: MITMIT waswas involvedinvolved inin thethe projectproject

�� 19521952:: NCNC achievedachieved whenwhen MITMIT demonstrateddemonstrated thatthat

simultaneoussimultaneous 33--axisaxis movementsmovements werewere possiblepossible usingusing aa

laboratorylaboratory--buildbuild controllercontroller andand aa CincinnatiCincinnati HYDROTELHYDROTEL

verticalvertical spindlespindle

�� 19551955:: afterafter refinementsrefinements NCNC becomebecome availableavailable toto industryindustry


� Early NC machines run off punched cards and tapetape

� Due to the time and effort for editing and changing tapes

ComputersComputers where introduced for programming

� Early NC machines run off punched cards and tapetape

� Due to the time and effort for editing and changing tapes

ComputersComputers where introduced for programming

Computers’ InvolvementComputers’ Involvement


Computer Aided Programming

Languages

Computer Aided Programming

Languages Direct Numerical ControlDirect Numerical Control


ComputerComputer AidedAided ProgrammingProgramming LanguagesLanguages::

�� AllowAllow thethe developmentdevelopment ofof anan NCNC programprogram usingusing aa setset ofof

universaluniversal “pidgin“pidgin English”English” commandscommands

�� ComputerComputer translatetranslate commandscommands intointo machinemachine codescodes

�� MachineMachine codescodes areare punchedpunched intointo thethe tapestapes

ComputerComputer AidedAided ProgrammingProgramming LanguagesLanguages::

�� AllowAllow thethe developmentdevelopment ofof anan NCNC programprogram usingusing aa setset ofof

universaluniversal “pidgin“pidgin English”English” commandscommands

�� ComputerComputer translatetranslate commandscommands intointo machinemachine codescodes

�� MachineMachine codescodes areare punchedpunched intointo thethe tapestapes


DirectDirect NumericalNumerical ControlControl::

�� AA computercomputer isis usedused asas aa partialpartial oror completecomplete controllercontroller ofof oneone

oror moremore NCNC machinesmachines

DirectDirect NumericalNumerical ControlControl::

�� AA computercomputer isis usedused asas aa partialpartial oror completecomplete controllercontroller ofof oneone

oror moremore NCNC machinesmachines


DirectDirect NumericalNumerical ControlControl (DNC)(DNC)::

�� ExpensiveExpensive mainframemainframe oror minimini--

computerscomputers werewere requiredrequired inin thethe pastpast

�� DueDue toto costcost thethe useuse ofof DNCDNC waswas

limitedlimited toto largelarge companiescompanies

DirectDirect NumericalNumerical ControlControl (DNC)(DNC)::

�� ExpensiveExpensive mainframemainframe oror minimini--

computerscomputers werewere requiredrequired inin thethe pastpast

�� DueDue toto costcost thethe useuse ofof DNCDNC waswas

limitedlimited toto largelarge companiescompanies


FIGURE 1FIGURE 1--1: Direct numerical control1: Direct numerical controlFIGURE 1FIGURE 1--1: Direct numerical control1: Direct numerical control

�� PowerfulPowerful PCsPCs givengiven riserise toto affordableaffordable

PCPC--basedbased DNCDNC systemssystems

�� MostMost ofof PCPC--basedbased DNCDNC systemssystems

runningrunning onon MSMS WindowsWindows OSOS

�� PowerfulPowerful PCsPCs givengiven riserise toto affordableaffordable

PCPC--basedbased DNCDNC systemssystems

�� MostMost ofof PCPC--basedbased DNCDNC systemssystems

runningrunning onon MSMS WindowsWindows OSOS


DistributedDistributed NumericalNumerical ControlControl (DNC)(DNC)::

�� AA networknetwork ofof computerscomputers isis usedused toto

coordinatecoordinate thethe operationoperation ofof aa numbernumber

ofof CNCCNC machinesmachines

�� UltimatelyUltimately anan entireentire factoryfactory cancan bebe

coordinatedcoordinated inin thisthis mannermanner

�� AlternativeAlternative SystemSystem 11:: NCNC programprogram isis

DistributedDistributed NumericalNumerical ControlControl (DNC)(DNC)::

�� AA networknetwork ofof computerscomputers isis usedused toto

coordinatecoordinate thethe operationoperation ofof aa numbernumber

ofof CNCCNC machinesmachines

�� UltimatelyUltimately anan entireentire factoryfactory cancan bebe

coordinatedcoordinated inin thisthis mannermanner



FIGURE 1FIGURE 1--2: Distributed numerical control2: Distributed numerical controlFIGURE 1FIGURE 1--2: Distributed numerical control2: Distributed numerical control


transferredtransferred inin itsits entiretyentirety fromfrom aa hosthost

computercomputer directlydirectly toto machinesmachines

controllercontroller


transferredtransferred fromfrom aa mainframemainframe oror aa

hosthost computercomputer toto aa PCPC onon thethe ShopShop

Floor,Floor, storedstored andand usedused whenwhen neededneeded

�� transferredtransferred toto machinemachine controllercontroller


transferredtransferred inin itsits entiretyentirety fromfrom aa hosthost

computercomputer directlydirectly toto machinesmachines



transferredtransferred fromfrom aa mainframemainframe oror aa

hosthost computercomputer toto aa PCPC onon thethe ShopShop

Floor,Floor, storedstored andand usedused whenwhen neededneeded

�� transferredtransferred toto machinemachine controllercontroller

CNC MachinesCNC Machines

�� AA CNCCNC machinemachine hashas moremore programmableprogrammable featuresfeatures thanthan

olderolder NCNC tapetape machinerymachinery

�� AA CNCCNC machinemachine maymay bebe usedused asas standstand--alonealone unitunit inin aa

networknetwork ofof machinesmachines –– FlexibleFlexible MachiningMachining CentersCenters oror

MachiningMachining CellsCells

�� CNCCNC machinesmachines areare easiereasier toto programprogram byby moremore thanthan oneone

�� AA CNCCNC machinemachine hashas moremore programmableprogrammable featuresfeatures thanthan

olderolder NCNC tapetape machinerymachinery

�� AA CNCCNC machinemachine maymay bebe usedused asas standstand--alonealone unitunit inin aa

networknetwork ofof machinesmachines –– FlexibleFlexible MachiningMachining CentersCenters oror

MachiningMachining CellsCells




methodmethod::

��OnOn boardboard computercomputer keyboardkeyboard

��TapeTape readerreader // electronicelectronic connectorconnector toto transfertransfer aa

programprogram toto CNCCNC machinemachine


methodmethod::

��OnOn boardboard computercomputer keyboardkeyboard

��TapeTape readerreader // electronicelectronic connectorconnector toto transfertransfer aa

programprogram toto CNCCNC machinemachine


AA CNCCNC machinemachine isis aa softsoft--wiredwired controllercontroller

�� OnceOnce thethe CNCCNC programprogram isis loadedloaded intointo thethe computer’scomputer’s

memorymemory nono HWHW isis requiredrequired toto transfertransfer thethe NCNC codescodes toto thethe


�� TheThe controllercontroller usesuses aa permanentpermanent residentresident programprogram ––

EXECUTIVEEXECUTIVE PROGRAMPROGRAM –– toto processprocess thethe codescodes intointo

electricalelectrical pulsespulses toto controlcontrol thethe machinemachine

AA CNCCNC machinemachine isis aa softsoft--wiredwired controllercontroller

�� OnceOnce thethe CNCCNC programprogram isis loadedloaded intointo thethe computer’scomputer’s

memorymemory nono HWHW isis requiredrequired toto transfertransfer thethe NCNC codescodes toto thethe


�� TheThe controllercontroller usesuses aa permanentpermanent residentresident programprogram ––

EXECUTIVEEXECUTIVE PROGRAMPROGRAM –– toto processprocess thethe codescodes intointo




�� EXECUTIVEEXECUTIVE ProgramProgram isis calledcalled “executive“executive software”software” oror

“executive“executive firmware”firmware”

��EXECUTIVEEXECUTIVE programprogram residesresides inin ROMROM (Read(Read OnlyOnly

Memory)Memory)

��NCNC codecode residesresides inin RAMRAM (Random(Random AccessAccess Memory)Memory)FirmwareFirmware:: RoutinesRoutines ofof SWSW includingincluding lowlow--levellevel instructionsinstructions storedstored inin ROMROM onlyonly forfor

readingreading


�� EXECUTIVEEXECUTIVE ProgramProgram isis calledcalled “executive“executive software”software” oror

“executive“executive firmware”firmware”

��EXECUTIVEEXECUTIVE programprogram residesresides inin ROMROM (Read(Read OnlyOnly

Memory)Memory)

��NCNC codecode residesresides inin RAMRAM (Random(Random AccessAccess Memory)Memory)FirmwareFirmware:: RoutinesRoutines ofof SWSW includingincluding lowlow--levellevel instructionsinstructions storedstored inin ROMROM onlyonly forfor

readingreading


ROMROM (Read(Read OnlyOnly Memory)Memory)

�� IsIs anan electronicelectronic chipchip whichwhich cancan bebe accessedaccessed byby aa computercomputer butbut notnot

alteredaltered (erased(erased oror written)written) withoutwithout specialspecial equipmentequipment

�� TheThe EXECUTIVEEXECUTIVE programprogram cancan notnot bebe erasederased

�� TheThe EXECUTIVEEXECUTIVE programprogram isis alwaysalways activeactive whenwhen machinemachine isis onon

RAMRAM (Random(Random AccessAccess Memory)Memory)

ROMROM (Read(Read OnlyOnly Memory)Memory)

�� IsIs anan electronicelectronic chipchip whichwhich cancan bebe accessedaccessed byby aa computercomputer butbut notnot

alteredaltered (erased(erased oror written)written) withoutwithout specialspecial equipmentequipment

�� TheThe EXECUTIVEEXECUTIVE programprogram cancan notnot bebe erasederased

�� TheThe EXECUTIVEEXECUTIVE programprogram isis alwaysalways activeactive whenwhen machinemachine isis onon

RAMRAM (Random(Random AccessAccess Memory)Memory)


�� RAMRAM cancan bebe alteredaltered byby thethe computercomputer

�� NCNC codecode isis writtenwritten intointo RAMRAM byby keyboardkeyboard oror otherother outsideoutside sourcesource

�� TheThe contentcontent ofof RAMRAM isis lostlost whenwhen thethe controllercontroller isis turnedturned offoff

�� BatteryBattery backupbackup systemsystem isis usedused forfor savingsaving thethe programprogram inin thethe eventevent

ofof powerpower lossloss

�� CMOSCMOS ((ComplementaryComplementary MetalMetal––OxideOxide––Semiconductor)Semiconductor) memorymemory

specialspecial typetype ofof RAMRAM whichwhich retainsretains thethe informationinformation contentcontent inin thethe

casecase ofof powerpower loosloos

�� RAMRAM cancan bebe alteredaltered byby thethe computercomputer

�� NCNC codecode isis writtenwritten intointo RAMRAM byby keyboardkeyboard oror otherother outsideoutside sourcesource

�� TheThe contentcontent ofof RAMRAM isis lostlost whenwhen thethe controllercontroller isis turnedturned offoff

�� BatteryBattery backupbackup systemsystem isis usedused forfor savingsaving thethe programprogram inin thethe eventevent

ofof powerpower lossloss

�� CMOSCMOS ((ComplementaryComplementary MetalMetal––OxideOxide––Semiconductor)Semiconductor) memorymemory

specialspecial typetype ofof RAMRAM whichwhich retainsretains thethe informationinformation contentcontent inin thethe

casecase ofof powerpower loosloos



FIGUREFIGURE 11--33 AA highhigh speedspeed 44--axisaxis verticalvertical machiningmachining

centercenter

FIGUREFIGURE 11--33 AA highhigh speedspeed 44--axisaxis verticalvertical machiningmachining

centercenter

FIGUREFIGURE 11--44 AA highhigh speedspeed 44--axisaxis horizontalhorizontal

machiningmachining centercenter

FIGUREFIGURE 11--44 AA highhigh speedspeed 44--axisaxis horizontalhorizontal




FIGUREFIGURE 11--55 AA

3311//22 axisaxis horizontalhorizontal machiningmachining centercenter

FIGUREFIGURE 11--55 AA

3311//22 axisaxis horizontalhorizontal machiningmachining centercenter

FIGUREFIGURE 11--66

AA TsugamiTsugami ‘’lightning’’‘’lightning’’ 33 ½½ axisaxis horizontalhorizontal


FIGUREFIGURE 11--66

AA TsugamiTsugami ‘’lightning’’‘’lightning’’ 33 ½½ axisaxis horizontalhorizontal




FIGURE 1FIGURE 1--7 A precision NC lathe7 A precision NC latheFIGURE 1FIGURE 1--7 A precision NC lathe7 A precision NC lathe FIGURE 1FIGURE 1--8 A NC lathe8 A NC latheFIGURE 1FIGURE 1--8 A NC lathe8 A NC lathe



FIGUREFIGURE 11--99

AA horizontalhorizontal machiningmachining centercenter equippedequipped withwith anan eighteight--palletpallet automaticautomatic workwork--changechange (Photo(Photo courtesycourtesy ofof

CincinnatiCincinnati Machine)Machine)

FIGUREFIGURE 11--99

AA horizontalhorizontal machiningmachining centercenter equippedequipped withwith anan eighteight--palletpallet automaticautomatic workwork--changechange (Photo(Photo courtesycourtesy ofof

CincinnatiCincinnati Machine)Machine)



FIGUREFIGURE 11--1010

AA CNCCNC centerlesscenterless grindinggrinding machinemachine withwith anan epoxyepoxy

granitegranite bed,bed, (Photo(Photo courtesycourtesy ofof CincinnatiCincinnati

Machine)Machine)

FIGUREFIGURE 11--1010

AA CNCCNC centerlesscenterless grindinggrinding machinemachine withwith anan epoxyepoxy

granitegranite bed,bed, (Photo(Photo courtesycourtesy ofof CincinnatiCincinnati

Machine)Machine)

Input MediaInput Media

InputInput MediaMedia forfor thethe NCNC codecode intointo thethe ControllerController

�� AreAre usedused toto electronicallyelectronically oror mechanicallymechanically storestore thethe NCNC programsprograms

�� AnAn NCNC programprogram isis readread fromfrom thethe inputinput mediummedium whenwhen itit isis loadedloaded intointo thethe

machinemachine

�� OldOld NCNC machinerymachinery couldcould onlyonly readread programsprograms fromfrom punchedpunched tapetape oror DNCDNC

�� CNCCNC machinesmachines maymay processprocess multiplemultiple meansmeans ofof programprogram inputinput

PunchedPunched TapeTape

�� TheThe oldestoldest mediummedium forfor programprogram storagestorage

InputInput MediaMedia forfor thethe NCNC codecode intointo thethe ControllerController

�� AreAre usedused toto electronicallyelectronically oror mechanicallymechanically storestore thethe NCNC programsprograms

�� AnAn NCNC programprogram isis readread fromfrom thethe inputinput mediummedium whenwhen itit isis loadedloaded intointo thethe

machinemachine

�� OldOld NCNC machinerymachinery couldcould onlyonly readread programsprograms fromfrom punchedpunched tapetape oror DNCDNC

�� CNCCNC machinesmachines maymay processprocess multiplemultiple meansmeans ofof programprogram inputinput

PunchedPunched TapeTape




�� MadeMade fromfrom paperpaper oror MylarMylar plasticplastic (stronger(stronger thanthan paper)paper)

�� TheThe NCNC programprogram codecode isis enteredentered intointo thethe tapetape byby tapetape puncherpuncher inin aa formform

ofof aa seriesseries ofof holesholes representingrepresenting thethe NCNC codescodes

�� AA tapetape readerreader byby electrical,electrical, opticaloptical oror mechanicalmechanical meansmeans sensessenses thethe

holesholes andand transferstransfers thethe codedcoded informationinformation intointo thethe machinemachine computercomputer

�� TheThe NCNC codecode isis enteredentered intointo CAMCAM oror WordWord ProcessorProcessor programprogram andand

punchedpunched intointo tapetape


�� MadeMade fromfrom paperpaper oror MylarMylar plasticplastic (stronger(stronger thanthan paper)paper)

�� TheThe NCNC programprogram codecode isis enteredentered intointo thethe tapetape byby tapetape puncherpuncher inin aa formform

ofof aa seriesseries ofof holesholes representingrepresenting thethe NCNC codescodes

�� AA tapetape readerreader byby electrical,electrical, opticaloptical oror mechanicalmechanical meansmeans sensessenses thethe

holesholes andand transferstransfers thethe codedcoded informationinformation intointo thethe machinemachine computercomputer

�� TheThe NCNC codecode isis enteredentered intointo CAMCAM oror WordWord ProcessorProcessor programprogram andand

punchedpunched intointo tapetape

Input MediaInput Media

MagneticMagnetic TapeTape

�� EarlyEarly experimentsexperiments werewere notnot successfulsuccessful duedue toto machinemachine shopshop environmentenvironment

�� HighHigh qualityquality tapestapes ofof todaytoday cancan bebe usedused withwith reasonablereasonable carecare inin handlinghandling

�� TheThe mostmost commonlycommonly usedused formatformat isis ¼¼ -- inchinch computercomputer cassettecassette tapetape

�� StandardsStandards forfor tapetape formatformat andand codingcoding havehave beenbeen developeddeveloped byby thethe

ElectronicsElectronics IndustriesIndustries AssociationAssociation (EIA)(EIA)

MagneticMagnetic TapeTape

�� EarlyEarly experimentsexperiments werewere notnot successfulsuccessful duedue toto machinemachine shopshop environmentenvironment

�� HighHigh qualityquality tapestapes ofof todaytoday cancan bebe usedused withwith reasonablereasonable carecare inin handlinghandling

�� TheThe mostmost commonlycommonly usedused formatformat isis ¼¼ -- inchinch computercomputer cassettecassette tapetape

�� StandardsStandards forfor tapetape formatformat andand codingcoding havehave beenbeen developeddeveloped byby thethe

ElectronicsElectronics IndustriesIndustries AssociationAssociation (EIA)(EIA)


FloppyFloppy DisketteDiskette

�� PopularizedPopularized byby thethe useuse ofof PCsPCs inin NCNC programmingprogramming

�� TheThe NCNC programprogram isis transferredtransferred intointo thethe CNCCNC controlcontrol byby meansmeans ofof aa

portableportable diskettediskette drivedrive attachedattached toto thethe communicationcommunication portport ofof thethe CNCCNC

machinemachine

�� TheThe mostmost commoncommon usedused portport isis RSRS232232 (serial(serial communicationcommunication port)port)

�� FloppyFloppy diskettesdiskettes areare cheapercheaper thanthan otherother programprogram storagestorage optionsoptions

FloppyFloppy DisketteDiskette

�� PopularizedPopularized byby thethe useuse ofof PCsPCs inin NCNC programmingprogramming

�� TheThe NCNC programprogram isis transferredtransferred intointo thethe CNCCNC controlcontrol byby meansmeans ofof aa

portableportable diskettediskette drivedrive attachedattached toto thethe communicationcommunication portport ofof thethe CNCCNC

machinemachine

�� TheThe mostmost commoncommon usedused portport isis RSRS232232 (serial(serial communicationcommunication port)port)

�� FloppyFloppy diskettesdiskettes areare cheapercheaper thanthan otherother programprogram storagestorage optionsoptions

Binary NumbersBinary Numbers

HowHow controllercontroller processesprocesses information?information?

�� ItIt isis importantimportant inin learninglearning toto programprogram CNCCNC machinerymachinery

�� ComputersComputers andand ComputerComputer-- ControlledControlled machinerymachinery dodo notnot dealdeal inin ArabicArabic

symbolssymbols oror numbersnumbers

�� AllAll ofof thethe internalinternal processingprocessing isis donedone byby calculatingcalculating oror comparingcomparing binarybinary

numbersnumbers

�� BinaryBinary numbersnumbers containcontain onlyonly twotwo digitsdigits:: ZEROZERO ((00)) andand ONEONE ((11))

�� WithinWithin CNCCNC controllercontroller::

HowHow controllercontroller processesprocesses information?information?

�� ItIt isis importantimportant inin learninglearning toto programprogram CNCCNC machinerymachinery

�� ComputersComputers andand ComputerComputer-- ControlledControlled machinerymachinery dodo notnot dealdeal inin ArabicArabic

symbolssymbols oror numbersnumbers

�� AllAll ofof thethe internalinternal processingprocessing isis donedone byby calculatingcalculating oror comparingcomparing binarybinary

numbersnumbers

�� BinaryBinary numbersnumbers containcontain onlyonly twotwo digitsdigits:: ZEROZERO ((00)) andand ONEONE ((11))




�� EachEach binarybinary digitdigit ““11”” maymay representrepresent aa “positive“positive charge”charge” oror

�� AA binarybinary digitdigit ““00”” maymay representrepresent aa “negative“negative charge”charge” oror

�� AA ““11”” maymay bebe thethe “ON”“ON” oror

�� AA ““00”” maymay bebe thethe “OFF”“OFF”

�� TheThe CNCCNC programprogram codecode inin binarybinary formform mustmust bebe loadedloaded intointo thethe computercomputer

�� ProgrammingProgramming formatsformats andand languageslanguages allowallow thethe NCNC codecode toto bebe writtenwritten

usingusing alphabeticalphabetic characterscharacters // basebase--tenten decimaldecimal numbersnumbers


�� EachEach binarybinary digitdigit ““11”” maymay representrepresent aa “positive“positive charge”charge” oror

�� AA binarybinary digitdigit ““00”” maymay representrepresent aa “negative“negative charge”charge” oror

�� AA ““11”” maymay bebe thethe “ON”“ON” oror

�� AA ““00”” maymay bebe thethe “OFF”“OFF”

�� TheThe CNCCNC programprogram codecode inin binarybinary formform mustmust bebe loadedloaded intointo thethe computercomputer

�� ProgrammingProgramming formatsformats andand languageslanguages allowallow thethe NCNC codecode toto bebe writtenwritten

usingusing alphabeticalphabetic characterscharacters // basebase--tenten decimaldecimal numbersnumbers

Binary NumbersBinary Numbers

�� WhenWhen thethe NCNC programprogram isis

punchedpunched oror recordedrecorded onon

tapetape oror otherother storagestorage mediamedia

thethe informationinformation isis

translatedtranslated toto binarybinary formform

�� WhenWhen thethe NCNC programprogram isis

punchedpunched oror recordedrecorded onon

tapetape oror otherother storagestorage mediamedia

thethe informationinformation isis

translatedtranslated toto binarybinary formform


FIGURE 1FIGURE 1--11 Binary numbers compared to Arabic numbers11 Binary numbers compared to Arabic numbersFIGURE 1FIGURE 1--11 Binary numbers compared to Arabic numbers11 Binary numbers compared to Arabic numbers

translatedtranslated toto binarybinary formformtranslatedtranslated toto binarybinary formform

Tape FormatsTape Formats

GeneralGeneral

�� ToadyToady punchedpunched tapetape isis notnot oftenoften usedused forfor NCNC programprogram storagestorage

�� FormatsFormats usedused inin NCNC programmingprogramming areare stillstill referredreferred asas TapeTape FormatsFormats

�� ComputerComputer filesfiles containingcontaining thethe NCNC programsprograms areare referredreferred asas “tape“tape files”,files”,

“punch“punch files”files” oror “tape“tape imageimage files”files”

�� OldOld machinerymachinery isis stillstill usedused inin machinemachine shopsshops

GeneralGeneral

�� ToadyToady punchedpunched tapetape isis notnot oftenoften usedused forfor NCNC programprogram storagestorage

�� FormatsFormats usedused inin NCNC programmingprogramming areare stillstill referredreferred asas TapeTape FormatsFormats

�� ComputerComputer filesfiles containingcontaining thethe NCNC programsprograms areare referredreferred asas “tape“tape files”,files”,

“punch“punch files”files” oror “tape“tape imageimage files”files”

�� OldOld machinerymachinery isis stillstill usedused inin machinemachine shopsshops


RSRS--274274 FormatFormat

�� FollowsFollows EElectronicslectronics IIndustriesndustries AAssociationssociation (EIA)(EIA) standardstandard

�� ProgramProgram informationinformation isis containedcontained inin programprogram lineslines calledcalled “Blocks”“Blocks”

�� “Blocks”“Blocks” areare punchedpunched intointo thethe tapetape inin oneone oror twotwo tapetape codecode standardsstandards

�� RSRS--274274 isis aa “variable“variable blockblock coding”coding” formatformat

�� TheThe informationinformation containedcontained inin aa blockblock maymay bebe arrangedarranged inin anyany orderorder


�� FollowsFollows EElectronicslectronics IIndustriesndustries AAssociationssociation (EIA)(EIA) standardstandard

�� ProgramProgram informationinformation isis containedcontained inin programprogram lineslines calledcalled “Blocks”“Blocks”

�� “Blocks”“Blocks” areare punchedpunched intointo thethe tapetape inin oneone oror twotwo tapetape codecode standardsstandards

�� RSRS--274274 isis aa “variable“variable blockblock coding”coding” formatformat

�� TheThe informationinformation containedcontained inin aa blockblock maymay bebe arrangedarranged inin anyany orderorder


RSRS--244244 BinaryBinary CodedCoded DecimalDecimal (BCD)(BCD)

�� TheThe EIAEIA RSRS--244244 standardstandard isis oneone ofof thethe twotwo tapetape codescodes usedused forfor NCNC tapestapes

�� BecameBecame aa standardstandard earlyearly inin thethe developmentdevelopment ofof NCNC –– limitedlimited punctuationpunctuation

�� EachEach holehole representsrepresents thethe digitdigit ““11”” whilewhile eacheach blankblank thethe digitdigit ““00””

�� TheThe tapetape codecode allowsallows alphabeticalphabetic characterscharacters andand basebase--tenten numbersnumbers toto bebe

translatedtranslated intointo thethe binarybinary codecode thethe controllercontroller requiresrequires ((BBinaryinary CCodedoded

DDecimalecimal –– BDC)BDC)


RSRS--244244 BinaryBinary CodedCoded DecimalDecimal (BCD)(BCD)

�� TheThe EIAEIA RSRS--244244 standardstandard isis oneone ofof thethe twotwo tapetape codescodes usedused forfor NCNC tapestapes

�� BecameBecame aa standardstandard earlyearly inin thethe developmentdevelopment ofof NCNC –– limitedlimited punctuationpunctuation

�� EachEach holehole representsrepresents thethe digitdigit ““11”” whilewhile eacheach blankblank thethe digitdigit ““00””

�� TheThe tapetape codecode allowsallows alphabeticalphabetic characterscharacters andand basebase--tenten numbersnumbers toto bebe

translatedtranslated intointo thethe binarybinary codecode thethe controllercontroller requiresrequires ((BBinaryinary CCodedoded

DDecimalecimal –– BDC)BDC)




�� Government,Government, telephonetelephone andand ComputerComputer industriesindustries requiredrequired tapetape codecode

containingcontaining upperupper andand lowerlower casecase lettersletters

�� TheThe existingexisting tapetape codingcoding formatsformats werewere sufficientsufficient onlyonly forfor machiningmachining

�� TheThe standardstandard acceptedaccepted waswas AAmericanmerican SStandardtandard CCodeode forfor IInformationnformation

IInterchangenterchange (ASCII)(ASCII)

�� EIAEIA RSRS--358358 waswas adoptedadopted

�� EIAEIA RSRS--358358 isis alsoalso asas ISOISO andand ASCIIASCII isis aa subsetsubset ofof thethe ASCIIASCII codecode usedused

inin otherother applicationsapplications –– TodayToday isis dominantdominant overover RSRS--244244


�� Government,Government, telephonetelephone andand ComputerComputer industriesindustries requiredrequired tapetape codecode

containingcontaining upperupper andand lowerlower casecase lettersletters

�� TheThe existingexisting tapetape codingcoding formatsformats werewere sufficientsufficient onlyonly forfor machiningmachining

�� TheThe standardstandard acceptedaccepted waswas AAmericanmerican SStandardtandard CCodeode forfor IInformationnformation

IInterchangenterchange (ASCII)(ASCII)

�� EIAEIA RSRS--358358 waswas adoptedadopted

�� EIAEIA RSRS--358358 isis alsoalso asas ISOISO andand ASCIIASCII isis aa subsetsubset ofof thethe ASCIIASCII codecode usedused

inin otherother applicationsapplications –– TodayToday isis dominantdominant overover RSRS--244244



FIGURE 1FIGURE 1--12, 112, 1--13 EIA RS13 EIA RS--244 tape code244 tape codeFIGURE 1FIGURE 1--12, 112, 1--13 EIA RS13 EIA RS--244 tape code244 tape code

Objectives of Numerical ControlObjectives of Numerical Control

NumericalNumerical controlcontrol (NC)(NC) waswas developeddeveloped withwith thesethese goalsgoals inin mindmind::

��ToTo increaseincrease productionproduction

��ToTo reducereduce laborlabor costscosts

��ToTo makemake productionproduction moremore economicaleconomical

��ToTo dodo jobsjobs thatthat wouldwould bebe impossibleimpossible oror impracticalimpractical withoutwithout NCNC

��ToTo increaseincrease thethe accuracyaccuracy ofof duplicateduplicate partsparts

NumericalNumerical controlcontrol (NC)(NC) waswas developeddeveloped withwith thesethese goalsgoals inin mindmind::

��ToTo increaseincrease productionproduction

��ToTo reducereduce laborlabor costscosts

��ToTo makemake productionproduction moremore economicaleconomical

��ToTo dodo jobsjobs thatthat wouldwould bebe impossibleimpossible oror impracticalimpractical withoutwithout NCNC

��ToTo increaseincrease thethe accuracyaccuracy ofof duplicateduplicate partsparts


Before deciding to utilize an NC or CNC machine for a particular job the Before deciding to utilize an NC or CNC machine for a particular job the

requirements and economics must be weighted against the advantages requirements and economics must be weighted against the advantages

and disadvantages of the machineryand disadvantages of the machinery

Before deciding to utilize an NC or CNC machine for a particular job the Before deciding to utilize an NC or CNC machine for a particular job the

requirements and economics must be weighted against the advantages requirements and economics must be weighted against the advantages

and disadvantages of the machineryand disadvantages of the machinery


AdvantagesAdvantages

�� IncreasedIncreased productivityproductivity

�� ReducedReduced tool/fixturetool/fixture storagestorage andand costcost

�� FasterFaster setupsetup timetime

�� ReducedReduced partsparts inventoryinventory

�� FlexibilityFlexibility thatthat speedsspeeds changeschanges inin designdesign

�� BetterBetter accuracyaccuracy ofof partsparts

AdvantagesAdvantages

�� IncreasedIncreased productivityproductivity

�� ReducedReduced tool/fixturetool/fixture storagestorage andand costcost

�� FasterFaster setupsetup timetime

�� ReducedReduced partsparts inventoryinventory

�� FlexibilityFlexibility thatthat speedsspeeds changeschanges inin designdesign




�� ReductionReduction inin partsparts handlinghandling

�� BetterBetter uniformityuniformity ofof partsparts

�� BetterBetter qualityquality controlcontrol

�� ImprovementImprovement inin manufacturingmanufacturing controlcontrol


�� ReductionReduction inin partsparts handlinghandling

�� BetterBetter uniformityuniformity ofof partsparts

�� BetterBetter qualityquality controlcontrol

�� ImprovementImprovement inin manufacturingmanufacturing controlcontrol


DisadvantagesDisadvantages

��IncreaseIncrease inin electricalelectrical maintenancemaintenance

��HighHigh initialinitial investmentinvestment

��HigherHigher perper--hourhour operatingoperating costcost thanthan traditionaltraditional machinemachine toolstools

��RetrainingRetraining ofof existingexisting personnelpersonnel

DisadvantagesDisadvantages

��IncreaseIncrease inin electricalelectrical maintenancemaintenance

��HighHigh initialinitial investmentinvestment

��HigherHigher perper--hourhour operatingoperating costcost thanthan traditionaltraditional machinemachine toolstools

��RetrainingRetraining ofof existingexisting personnelpersonnel


NC is a general term used for Numerical Control. CNC refers NC is a general term used for Numerical Control. CNC refers

specifically to COMPUTER NUMERICAL CONTROL. CNC machines are specifically to COMPUTER NUMERICAL CONTROL. CNC machines are

all NC machines but not all NC machines are CNC machinesall NC machines but not all NC machines are CNC machines

NC is a general term used for Numerical Control. CNC refers NC is a general term used for Numerical Control. CNC refers

specifically to COMPUTER NUMERICAL CONTROL. CNC machines are specifically to COMPUTER NUMERICAL CONTROL. CNC machines are

all NC machines but not all NC machines are CNC machinesall NC machines but not all NC machines are CNC machines

Applications in IndustryApplications in Industry

�� OriginallyOriginally developeddeveloped forfor useuse inin AerospaceAerospace industriesindustries

�� WidespreadWidespread inin manufacturingmanufacturing::

�� AerospaceAerospace

�� DefenceDefence

�� AutomotiveAutomotive

�� ElectronicElectronic

�� ApplianceAppliance

�� OriginallyOriginally developeddeveloped forfor useuse inin AerospaceAerospace industriesindustries

�� WidespreadWidespread inin manufacturingmanufacturing::

�� AerospaceAerospace

�� DefenceDefence

�� AutomotiveAutomotive

�� ElectronicElectronic




�� ToolingTooling industriesindustries

�� AdvancesAdvances inin microelectronicsmicroelectronics havehave loweredlowered thethe costcost ofof acquiringacquiring CNCCNC

equipmentequipment

�� Bending,Bending, Forming,Forming, StampingStamping andand InspectionInspection MachinesMachines havehave beenbeen

producedproduced asas NCNC systemssystems


�� ToolingTooling industriesindustries

�� AdvancesAdvances inin microelectronicsmicroelectronics havehave loweredlowered thethe costcost ofof acquiringacquiring CNCCNC

equipmentequipment

�� Bending,Bending, Forming,Forming, StampingStamping andand InspectionInspection MachinesMachines havehave beenbeen

producedproduced asas NCNC systemssystems

Summary 1/2Summary 1/2

�� AnAn NCNC machinemachine isis aa machinemachine positionedpositioned automaticallyautomatically alongalong aa

preprogrammedpreprogrammed pathpath byby wayway ofof codedcoded instructionsinstructions

�� DNCDNC involvesinvolves aa computercomputer thatthat actsacts asas aa partialpartial oror fullfull controllercontroller toto

oneone oror moremore NCNC machinesmachines

�� DistributiveDistributive NCNC isis aa networknetwork ofof computerscomputers andand NCNC machinerymachinery

�� AnAn NCNC machinemachine isis aa machinemachine positionedpositioned automaticallyautomatically alongalong aa

preprogrammedpreprogrammed pathpath byby wayway ofof codedcoded instructionsinstructions

�� DNCDNC involvesinvolves aa computercomputer thatthat actsacts asas aa partialpartial oror fullfull controllercontroller toto

oneone oror moremore NCNC machinesmachines




coordinatedcoordinated toto performperform somesome tasktask

�� CNCCNC machinesmachines useuse anan onon--boardboard computercomputer asas aa controllercontroller

�� OfflineOffline programmingprogramming isis thethe programmingprogramming ofof aa partpart awayaway fromfrom thethe

computercomputer keyboardkeyboard -- usuallyusually donedone withwith aa micromicro--computercomputer..


coordinatedcoordinated toto performperform somesome tasktask

�� CNCCNC machinesmachines useuse anan onon--boardboard computercomputer asas aa controllercontroller

�� OfflineOffline programmingprogramming isis thethe programmingprogramming ofof aa partpart awayaway fromfrom thethe

computercomputer keyboardkeyboard -- usuallyusually donedone withwith aa micromicro--computercomputer..

Summary 2/2Summary 2/2

�� ThereThere areare fourfour waysways toto inputinput programsprograms intointo CNCCNC machinerymachinery::

��MDIMDI (Manual(Manual DataData Input)Input)

��PunchedPunched TapeTape

��MagneticMagnetic TapeTape

��DNCDNC (Direct(Direct NumericalNumerical ControlControl // DistributiveDistributive NumericalNumerical Control)Control)

�� TheThe CNCCNC programprogram mustmust bebe loadedloaded intointo thethe controllercontroller inin binarybinary formform

�� ThereThere areare fourfour waysways toto inputinput programsprograms intointo CNCCNC machinerymachinery::

��MDIMDI (Manual(Manual DataData Input)Input)

��PunchedPunched TapeTape

��MagneticMagnetic TapeTape

��DNCDNC (Direct(Direct NumericalNumerical ControlControl // DistributiveDistributive NumericalNumerical Control)Control)




�� RSRS--244244 andand RSRS--358358 tapetape codescodes usedused toto placeplace informationinformation onon punchedpunched

tapetape informationinformation beingbeing punchedpunched intointo thethe tapetape inin binarybinary formform

�� BeforeBefore decidingdeciding onon aa NCNC machinemachine forfor aa specificspecific job,job, thethe advantagesadvantages

andand disadvantagesdisadvantages ofof NCNC mustmust bebe weighedweighed inin viewview ofof thethe primaryprimary

objectivesobjectives ofof numericalnumerical controlcontrol


�� RSRS--244244 andand RSRS--358358 tapetape codescodes usedused toto placeplace informationinformation onon punchedpunched

tapetape informationinformation beingbeing punchedpunched intointo thethe tapetape inin binarybinary formform

�� BeforeBefore decidingdeciding onon aa NCNC machinemachine forfor aa specificspecific job,job, thethe advantagesadvantages

andand disadvantagesdisadvantages ofof NCNC mustmust bebe weighedweighed inin viewview ofof thethe primaryprimary

objectivesobjectives ofof numericalnumerical controlcontrol

Vocabulary Introduced in this chapterVocabulary Introduced in this chapter

�� ASCIIASCII

�� BinaryBinary codedcoded decimaldecimal (BCD)(BCD)

�� ComputerComputer AidedAided ProgrammingProgramming (CAP)(CAP)

�� ComputerComputer NumericalNumerical ControlControl (CNC)(CNC)

�� DirectDirect NumericalNumerical ControlControl (DNC)(DNC)

�� DistributiveDistributive numericalnumerical controlcontrol

�� InputInput mediamedia

�� ASCIIASCII

�� BinaryBinary codedcoded decimaldecimal (BCD)(BCD)

�� ComputerComputer AidedAided ProgrammingProgramming (CAP)(CAP)

�� ComputerComputer NumericalNumerical ControlControl (CNC)(CNC)

�� DirectDirect NumericalNumerical ControlControl (DNC)(DNC)

�� DistributiveDistributive numericalnumerical controlcontrol




�� ManualManual DataData InputInput (MDI)(MDI)

�� ManualManual partpart programmingprogramming

�� NumericalNumerical controlcontrol (NC)(NC)

�� RandomRandom AccessAccess MemoryMemory (RAM)(RAM)

�� ReadRead--onlyonly MemoryMemory (ROM)(ROM)

�� WordWord addressaddress formatformat


�� ManualManual DataData InputInput (MDI)(MDI)

�� ManualManual partpart programmingprogramming

�� NumericalNumerical controlcontrol (NC)(NC)

�� RandomRandom AccessAccess MemoryMemory (RAM)(RAM)

�� ReadRead--onlyonly MemoryMemory (ROM)(ROM)

�� WordWord addressaddress formatformat

cnc chapter 1 lecture

Documents