Manufacturing System - Intro
Transcript of Manufacturing System - Intro
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Manufacturing SystemsManufacturing Systems
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Manufacturing SystemManufacturing System --
DefinitionDefinition From Latin wordsFrom Latin words ManuManu FactusFactus
DefinitionDefinition
Transformation of materials and information into usefulTransformation of materials and information into usefulproducts (goods)products (goods)
ProductionProduction -- ManufacturingManufacturing
Defining Manufacturing by System TheoryDefining Manufacturing by System TheoryInputInput ProcessProcess Output OutputMaterialsMaterials DesignDesign GoodsGoods
ManpowerManpower Mfg ProcessesMfg ProcessesCapitalCapital Management Management
EnergyEnergy
TechnologyTechnology
DemandDemand SatisfactionSatisfaction
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Types of ProductionTypes of Production
Mass ProductionMass Production Large Quantity (in Millions)Large Quantity (in Millions)
ContinuousContinuous
Specialized MachinerySpecialized Machinery
Low Unit CostLow Unit Cost Assured DemandAssured Demand
High Rate of ProductionHigh Rate of Production
Examples:Examples: Nuts, BoltsNuts, Bolts
Light BulbsLight Bulbs
Batch ProductionBatch Production Small Quantity (Upto thousands)Small Quantity (Upto thousands)
In BatchesIn Batches
General Purpose MachineryGeneral Purpose Machinery
High Unit CostHigh Unit Cost
Made to OrderMade to Order
Low Rate of ProductionLow Rate of Production
Examples:Examples: Large Power GeneratorsLarge Power Generators
AirplanesAirplanes
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Other ClassificationsOther Classifications
ManualManual
MechanizedMechanized
AutomatedAutomated RigidRigid
FlexibleFlexible
LeanLean
CellularCellular
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Main Attributes ofMain Attributes of
Manufacturing SystemManufacturing System
CostCost
TimeTimeQualityQuality
FlexibilityFlexibility
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Cost ElementsCost Elements
Cost of Equipment (Capital Cost)Cost of Equipment (Capital Cost)
Labour CostLabour Cost Material CostMaterial Cost
Energy CostEnergy Cost
Maintenance CostMaintenance Cost Training CostTraining Cost
MiscMisc
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For Capital costFor Capital cost --------------------------
Consider Following ExampleConsider Following Example
CNC LatheCNC Lathe Capital CostCapital Cost Rs 2.5 MilRs 2.5 Mil
Estimated LifeEstimated Life 5 Years5 Years Operation Based on :Operation Based on :
300 days/year300 days/year
16 hours/day16 hours/day
Machine hourly rate:Machine hourly rate:--
2.5x1000,000/5x300x162.5x1000,000/5x300x16
=Rs 1042 per hr=Rs 1042 per hr
Conventional LatheConventional Lathe Capital CostCapital Cost Rs 0.25 MilRs 0.25 Mil
Estimated LifeEstimated Life 5 Years5 Years Operation Based on :Operation Based on :
300 days/year300 days/year
16 hours/day16 hours/day
Machine hourly rate:Machine hourly rate:--
0.25x1000,000/5x300x160.25x1000,000/5x300x16=Rs 104 per hr=Rs 104 per hr
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Work Centre CostWork Centre Cost
It is generally taken as addition ofIt is generally taken as addition of a,b,ca,b,c..
a.a. Capital Cost (Machine Hourly Rate) sayCapital Cost (Machine Hourly Rate) say
370/hr370/hr
b.b. Labour Rate say 120/hrLabour Rate say 120/hr
c.c. O/H say (40% of a) and (55% of b) aboveO/H say (40% of a) and (55% of b) above
Work Centre Cost =Work Centre Cost =370+120+(0.4x370+0.55x120)370+120+(0.4x370+0.55x120)
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Analyzing Cost perAnalyzing Cost perPiece.Piece.
Consider Following ExampleConsider Following ExampleA batch of 150 Part X is machined from 35mm barA batch of 150 Part X is machined from 35mm barstock costing Rs 1800/m. Work centre hourly rate isstock costing Rs 1800/m. Work centre hourly rate is
Rs 705. The machine setup time is 25 hrs, and eachRs 705. The machine setup time is 25 hrs, and eachpart requires 37 min of machining. The job requirespart requires 37 min of machining. The job requiresa single cutting tool costing Rs 610 which lasts for 7a single cutting tool costing Rs 610 which lasts for 7workpieces. Tool change time is 20 min. The cost ofworkpieces. Tool change time is 20 min. The cost ofindirect materials is Rs1184.indirect materials is Rs1184.
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Analyzing Cost per PieceAnalyzing Cost per Piece
Material CostMaterial Cost DirectDirect = 35/1000 x1800= 35/1000 x1800 =Rs63.00/piece=Rs63.00/piece
IndirectIndirect = 1184/150= 1184/150 =Rs7.90/piece=Rs7.90/piece
ToolTool = 610/7= 610/7 =Rs87.14/piece=Rs87.14/piece
Work Centre CostWork Centre Cost SetupSetup = 25/150 x= 25/150 x 705 =Rs117.50/piece705 =Rs117.50/piece
MachiningMachining =37/60x705 = Rs 434.75/piece=37/60x705 = Rs 434.75/piece
Tool Change=20/60x1/7x705=Rs33.57/pieceTool Change=20/60x1/7x705=Rs33.57/piece
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0.00
50.00
100.00
150.00
200.00
250.00
300.00
350.00400.00
450.00
500.00
Dir Material Indir
Material
Tool
Material
Set Up Machining Tool
Change
Analyzing Cost per PieceAnalyzing Cost per Piece
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Time!Time!
AvailabilityAvailability
Percentage of the total time thePercentage of the total time theequipment is available for production.equipment is available for production.
ReliabilityReliability
Probability that the equipment willProbability that the equipment willcontinue to remain operational forcontinue to remain operational forcertain specified length of time.certain specified length of time.
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Availability AAvailability A
A = MTBF/(MTBF+MTTR)A = MTBF/(MTBF+MTTR)
MTBFMTBF=Mean Time Between Failures=Mean Time Between Failures
MTTRMTTR=Mean Time to Repair=Mean Time to Repair
5 11 4 7 4 7 35 11 4 7 4 7 3
42 44 87 23 22 21 26 2542 44 87 23 22 21 26 25
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Reliability RReliability R
tt
RR = e= e
WhereWhere = 1/MTBF (Failure= 1/MTBF (FailureRate)Rate)
And t = Mission Time And t = Mission Time
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HereHere = 1/41.43= 1/41.43
= 0.0241= 0.0241
Let us assume 2 shift x 8 hour operationLet us assume 2 shift x 8 hour operationor mission time, thenor mission time, then
-- (0.0241x16)(0.0241x16)
RR = e= e = 0.68 or 68 %= 0.68 or 68 %
Reliability RReliability R
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= .00023 = .00027= .0073= .00025
= .00023+.00025+.0073+.0027
= .00805
Let t=16, Reliability R will be
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tR = e
= 0.87987 or 87.9 %
Consider Following Example.Consider Following Example.
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= .00023 = .00027= .0073= .00025
= .00023+.00025+.001825 +.00027
= .002575
Let t=16, Reliability R will be
- tR = e
= 0.9596 or 95.96 %
= .0073
= .0073
= .0073
With Redundancy,With Redundancy,Notice the increaseNotice the increase
in Rin R
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QualityQuality
Capability Index (Cp)Capability Index (Cp)Cp = UCLCp = UCL--LCL (say Tolerance) / 6LCL (say Tolerance) / 6
Explanation:Explanation: In this formula, USL and LSLIn this formula, USL and LSLare the upper and lower specification limitsare the upper and lower specification limitsof the quality characteristic of theof the quality characteristic of the productproduct,,respectively. The quantity in therespectively. The quantity in the
denominator, 6denominator, 6 signifies the fact thatsignifies the fact that99.73% of the values generated by the99.73% of the values generated by theprocessprocess is contained within.is contained within.
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Machine Accuracy
Product Tolerance
Cp = 14/6 = 2.33Mfg Process too accurate for the product.
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Product Tolerance
Machine Accuracy
Cp = 2/6 = 0.33 Mfg Process too rough / inaccurate for the product.
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Product Tolerance
Machine Accuracy
Cp = 6.1/6 = 1.02 . The mfg process is well suited for the job.
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Quality :Quality : Consider FollowingConsider Following
Example.Example.
Part Tolerance + 10Part Tolerance + 10 mm
Machine Accuracy (Following random error dataMachine Accuracy (Following random error data
available. All values in m.)available. All values in m.)22 --33 --1 3 1 3 21 3 1 3 2 --2 12 1 --33 --1 01 0
Standard DeviationStandard Deviation ==
Cp = Tolerance/6Cp = Tolerance/6 = == =
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FlexibilityFlexibility
Flexibility of the Mfg System can beFlexibility of the Mfg System can bedefined asdefined as the ease with which thethe ease with which the
production can be changed..production can be changed.. Product, capacity or Process FlexibilityProduct, capacity or Process Flexibility
Product Type can be changedProduct Type can be changed Product flexibilityProduct flexibility
Product Volume can be changedProduct Volume can be changed CapacityCapacity
FlexibilityFlexibility Manufacturing Process can be changedManufacturing Process can be changed ProcessProcessFlexibilityFlexibility
..depending upon how easily..depending upon how easilythese parameters can be altered.these parameters can be altered.
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Penalty of Change (POC) can be calculated for each mfgPenalty of Change (POC) can be calculated for each mfgsystem as followssystem as follows
Product A Product B Product C POCProduct A Product B Product C POC
Sys ISys I 3(.5)3(.5) 2(.3)2(.3) 6(.2)6(.2) 3.33.3
Sys II 5(.5)Sys II 5(.5) 7(.3)7(.3) 1(.2)1(.2) 4.84.8
Sys III 7(.5)Sys III 7(.5) 2(.3)2(.3) 1(.2)1(.2) 4.34.3
Since POC is minimum for Sys I (3.3), it is the most flexible.Since POC is minimum for Sys I (3.3), it is the most flexible.
Flexibility: ExampleFlexibility: Example
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Evolution of Manufacturing Systems in last 50 yearsEvolution of Manufacturing Systems in last 50 years
TimeTimeDurationDuration
DrivingDrivingForceForce
ManufacturingManufacturingStrategyStrategy
SupportSupportSystemsSystems
1960s1960s Cost Cost(Selling)(Selling)
MechanizationMechanization PPC, InvPPC, InvControlControl
1970s1970s Market Market Automation,Automation,DiversificationDiversification
MRPMRP--1, MPS,1, MPS,PUSHPUSH
1980s1980s QualityQuality Process ControlProcess Control MRPMRP--II, PULL,II, PULL,SQCSQC
1990s1990s Time toTime toMarketMarket Responsiveness,Responsiveness,ReengineeringReengineering
CIM, TQMCIM, TQM
2000s2000s Service &Service &ValueValue
Info Sharing, LifeInfo Sharing, LifeCycle, EnvironmentCycle, Environment
Paperless,Paperless,SafetySafety
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The EndThe End
Any Questions?Any Questions?