Quản trị kinh doanh - Chapter 7: Capacity and facilities

Chapter 7Capacity and Facilities1Lecture OutlineCapacity PlanningBasic LayoutsDesigning Process LayoutsDesigning Service LayoutsDesigning Product LayoutsHybrid LayoutsCopyright 2011 John Wiley & Sons, Inc.7-2CapacityMaximum capability to produceCapacity planningestablishes overall level of productive resources for a firm3 basic strategies for timing of capacity expansion in relation to steady growth in demand (lead, lag, and average)Copyright 2011 John Wiley & Sons, Inc.7-3Capacity Expansion StrategiesCopyright 2011 John Wiley & Sons, Inc.7-4CapacityCapacity increase depends onvolume and certainty of anticipated demandstrategic objectivescosts of expansion and operationBest operating level% of capacity utilization that minimizes unit costsCapacity cushion% of capacity held in reserve for unexpected occurrencesCopyright 2011 John Wiley & Sons, Inc.7-5Economies of ScaleUnit cost decreases as output volume increasesfixed costs can be spread over a larger number of unitsproduction or operating costs do not increase linearly with output levelsquantity discounts are available for material purchasesoperating efficiency increases as workers gain experienceCopyright 2011 John Wiley & Sons, Inc.7-6Best Operating Level for a HotelCopyright 2011 John Wiley & Sons, Inc.7-7Objectives of Facility LayoutMinimize material-handling costsUtilize space efficientlyUtilize labor efficientlyEliminate bottlenecksFacilitate communication and interactionReduce manufacturing cycle timeReduce customer service timeEliminate wasted or redundant movement7-8Copyright 2011 John Wiley & Sons, Inc.Objectives of Facility LayoutFacilitate entry, exit, and placement of material, products, and peopleIncorporate safety and security measuresPromote product and service qualityEncourage proper maintenance activitiesProvide a visual control of activitiesProvide flexibility to adapt to changing conditionsIncrease capacity7-9Copyright 2011 John Wiley & Sons, Inc.Basic LayoutsProcess layoutsgroup similar activities together according to process or function they performProduct layoutsarrange activities in line according to sequence of operations for a particular product or serviceFixed-position layoutsare used for projects in which product cannot be movedCopyright 2011 John Wiley & Sons, Inc.7-10Process Layout in ServicesCopyright 2011 John Wiley & Sons, Inc.7-11Women’s lingerieWomen’s dressesWomen’s sportswearShoesCosmetics and jewelryEntry and display areaHousewaresChildren’s departmentMen’s departmentManufacturing Process LayoutCopyright 2011 John Wiley & Sons, Inc.7-12A Product LayoutCopyright 2011 John Wiley & Sons, Inc.7-13InOutDescriptionType of processProductDemandVolumeEquipmentCopyright 2011 John Wiley & Sons, Inc.7-14Sequential arrangement of activitiesContinuous, mass production, mainly assemblyStandardized, made to stock StableHighSpecial purposeProcessFunctional grouping of activitiesIntermittent, job shop, batch production, mainly fabricationVaried, made to order FluctuatingLowGeneral purposeProductComparison of Product and Process LayoutsWorkersInventoryStorage spaceMaterial handlingAislesSchedulingLayout decisionGoalAdvantageCopyright 2011 John Wiley & Sons, Inc.7-15Limited skillsLow in-process, high finished goodsSmallFixed path (conveyor)NarrowPart of balancingLine balancingEqualize work at each stationEfficiencyProcessVaried skillsHigh in-process, low finished goodsLargeVariable path (forklift)WideDynamicMachine locationMinimize material handling costFlexibilityProductComparison of Product and Process LayoutsFixed-Position LayoutsTypical of projects Fragile, bulky, heavy itemsEquipment, workers & materials brought to siteLow equipment utilizationHighly skilled laborTypically low fixed costOften high variable costs7-16Designing Process LayoutsGoal: minimize material handling costsBlock Diagrammingminimize nonadjacent loads use when quantitative data is availableRelationship Diagrammingbased on location preference between areasuse when quantitative data is not availableCopyright 2011 John Wiley & Sons, Inc.7-17Block DiagrammingUnit loadquantity in which material is normally movedNonadjacent loaddistance farther than the next blockStepscreate load summary chartcalculate composite (two way) movementsdevelop trial layouts minimizing number of nonadjacent loadsCopyright 2011 John Wiley & Sons, Inc.7-18Copyright 2011 John Wiley & Sons, Inc.7-19Block Diagramming: ExampleDepartment 1 2 3 4 5Load Summary ChartFROM/TO DEPARTMENT1 — 100 502 — 200 503 60 — 40 504 100 — 605 50 —12345Block Diagramming: ExampleCopyright 2011 John Wiley & Sons, Inc.7-202 3 200 loads2 4 150 loads1 3 110 loads1 2 100 loads4 5 60 loads3 5 50 loads2 5 50 loads3 4 40 loads1 4 0 loads1 5 0 loads1234510020015050506040110Grid 1Nonadjacent Loads 110+40=150Block Diagramming: ExampleCopyright 2011 John Wiley & Sons, Inc.7-212 3 200 loads2 4 150 loads1 3 110 loads1 2 100 loads4 5 60 loads3 5 50 loads2 5 50 loads3 4 40 loads1 4 0 loads1 5 0 loads1234510020015050506040110Grid 2Nonadjacent Loads: 0Block Diagramtype of schematic layout diagram; includes space requirementsCopyright 2011 John Wiley & Sons, Inc.7-221234532514(a) Initial block diagram(b) Final block diagramBlock Diagramming: ExampleBlock Diagramming With ExcelCopyright 2011 John Wiley & Sons, Inc.7-23Input load summarychart and trial layoutTry different layoutconfigurationsExcel will calculatecomposite movementsand nonadjacent loadsRelationship DiagrammingSchematic diagram that uses weighted lines to denote location preferenceMuther’s gridformat for displaying manager preferences for department locationsCopyright 2011 John Wiley & Sons, Inc.7-24Copyright 2011 John Wiley & Sons, Inc.7-25ProductionOfficesStockroomShipping and receivingLocker roomToolroomAAA OOOOO UU U UEX IA Absolutely necessaryE Especially importantI ImportantO OkayU UnimportantX UndesirableRelationship DiagrammingCopyright 2011 John Wiley & Sons, Inc.7-26(a) Relationship diagram of original layoutKey: A E I O U XOfficesStockroomLocker roomToolroomShipping and receivingProductionRelationship Diagramming(b) Relationship diagram of revised layoutRelationship DiagrammingCopyright 2011 John Wiley & Sons, Inc.7-27OfficesStockroomLocker roomToolroomShipping and receivingProductionKey: A E I O U XComputerized Layout SolutionsCRAFTComputerized Relative Allocation of Facilities TechniqueCORELAPComputerized Relationship Layout PlanningPROMODEL and EXTENDvisual feedbackallow user to quickly test a variety of scenariosThree-D modeling and CAD integrated layout analysisavailable in VisFactory and similar softwareCopyright 2011 John Wiley & Sons, Inc.7-28Designing Service LayoutsMust be both attractive and functionalFree flow layoutsencourage browsing, increase impulse purchasing, are flexible and visually appealingGrid layoutsencourage customer familiarity, are low cost, easy to clean and secure, and good for repeat customersLoop and Spine layoutsboth increase customer sightlines and exposure to products, while encouraging customer to circulate through the entire storeCopyright 2011 John Wiley & Sons, Inc.7-29Types of Store LayoutsCopyright 2011 John Wiley & Sons, Inc.7-30Designing Product LayoutsObjectiveBalance the assembly lineLine balancingtries to equalize the amount of work at each workstationPrecedence requirementsphysical restrictions on the order in which operations are performedCycle timemaximum amount of time a product is allowed to spend at each workstationCopyright 2011 John Wiley & Sons, Inc.7-31Cycle Time ExampleCopyright 2011 John Wiley & Sons, Inc.7-32Cd = production time availabledesired units of outputCd = (8 hours x 60 minutes / hour)(120 units)Cd = = 4 minutes480120Flow Time vs Cycle TimeCycle time = max time spent at any station Flow time = time to complete all stationsCopyright 2011 John Wiley & Sons, Inc.7-331234 minutes4 minutes4 minutesFlow time = 4 + 4 + 4 = 12 minutesCycle time = max (4, 4, 4) = 4 minutesEfficiency of Line and Balance Delay7-34ji = 1tinCaE =ji = 1tiCdN =EfficiencyMin# of workstationswhere ti = completion time for element i j = number of work elements n = actual number of workstations Ca = actual cycle time Cd = desired cycle timeBalance delaytotal idle time of line = nCa -Copyright 2011 John Wiley & Sons, Inc.ji = 1tiLine Balancing ProcedureDraw and label a precedence diagramCalculate desired cycle time required for lineCalculate theoretical minimum number of workstationsGroup elements into workstations, recognizing cycle time and precedence constraintsCalculate efficiency of lineDetermine if theoretical minimum number of workstations or an acceptable efficiency level has been reached. If not, go back to step 4.Copyright 2011 John Wiley & Sons, Inc.7-35Line BalancingCopyright 2011 John Wiley & Sons, Inc.7-360.10.20.40.3DBCA Work Element Precedence Time (Min)A Press out sheet of fruit — 0.1B Cut into strips A 0.2C Outline fun shapes A 0.4D Roll up and package B, C 0.3Line BalancingCopyright 2011 John Wiley & Sons, Inc.7-37Cd = = = 0.4 minute40 hours x 60 minutes / hour6,000 units24006000N = = = 2.5  3 workstations1.00.40.1 + 0.2 + 0.3 + 0.40.4 Work Element Precedence Time (Min)A Press out sheet of fruit — 0.1B Cut into strips A 0.2C Outline fun shapes A 0.4D Roll up and package B, C 0.3Line BalancingCopyright 2011 John Wiley & Sons, Inc.7-38Cd = 0.4N = 2.50.10.20.40.3DBCA Remaining Remaining Workstation Element Time Elements1 A 0.3 B, C B 0.1 C, D2 C 0.0 D3 D 0.1 noneLine BalancingCopyright 2011 John Wiley & Sons, Inc.7-39A, BCDWork station 1Work station 2Work station 30.3 minute0.4 minute0.3 minuteCd = 0.4N = 2.5E = = = 0.833 = 83.3%0.1 + 0.2 + 0.3 + 0.43(0.4)1.01.2Computerized Line BalancingUse heuristics to assign tasks to workstationsLongest operation timeShortest operation timeMost number of following tasksLeast number of following tasksRanked positional weightCopyright 2011 John Wiley & Sons, Inc.7-40Hybrid LayoutsCellular layoutsgroup dissimilar machines into work centers (called cells) that process families of parts with similar shapes or processing requirementsProduction flow analysis (PFA)reorders part routing matrices to identify families of parts with similar processing requirementsFlexible manufacturing systemautomated machining and material handling systems which can produce an enormous variety of itemsMixed-model assembly lineprocesses more than one product model in one lineCopyright 2011 John Wiley & Sons, Inc.7-41Cellular LayoutsIdentify families of parts with similar flow pathsGroup machines into cells based on part familiesArrange cells so material movement is minimizedLocate large shared machines at point of useCopyright 2011 John Wiley & Sons, Inc.7-42Parts FamiliesCopyright 2011 John Wiley & Sons, Inc.7-43A family of similar partsA family of related grocery itemsOriginal Process LayoutCopyright 2011 John Wiley & Sons, Inc.7-44CABRaw materialsAssembly123456789101112Part Routing MatrixCopyright 2011 John Wiley & Sons, Inc.7-45 Machines Parts 1 2 3 4 5 6 7 8 9 10 11 12 A x x x x x B x x x x C x x x D x x x x x E x x x F x x x G x x x x H x x xFigure 5.8Revised Cellular LayoutCopyright 2011 John Wiley & Sons, Inc.7-46369Assembly124810571112A B CRaw materialsCell 1Cell 2Cell 3Reordered Routing MatrixCopyright 2011 John Wiley & Sons, Inc.7-47 Machines Parts 1 2 4 8 10 3 6 9 5 7 11 12 A x x x x x D x x x x x F x x x C x x x G x x x x B x x x x H x x x E x x xCopyright 2011 John Wiley & Sons, Inc.7-48Cellular LayoutsAdvantagesReduced material handling and transit timeReduced setup timeReduced work-in- process inventory Better use of human resourcesEasier to controlEasier to automateDisadvantagesInadequate part familiesPoorly balanced cellsExpanded training and scheduling of workersIncreased capital investmentCopyright 2011 John Wiley & Sons, Inc.7-49Automated Manufacturing CellCopyright 2011 John Wiley & Sons, Inc.7-50Flexible Manufacturing Systems (FMS)Consists of programmable machine tools automated tool changingautomated material handling systemcontrolled by computer networkCombines flexibility with efficiencyLayouts differ based onvariety of parts the system can processsize of parts processedaverage processing time required for part completionCopyright 2011 John Wiley & Sons, Inc.7-51Fully-Implemented FMSCopyright 2011 John Wiley & Sons, Inc.7-52Mixed Model Assembly LinesProduce multiple models in any order on one assembly lineFactors in mixed model linesLine balancingU-shaped linesFlexible workforceModel sequencingCopyright 2011 John Wiley & Sons, Inc.7-53Balancing U-Shaped LinesCopyright 2011 John Wiley & Sons, Inc.ABCDEPrecedence diagram:Cycle time = 12 minA,BC,DE(a) Balanced for a straight line9 min 12 min 3 minEfficiency = = = .6666 = 66.7 %2436243(12)12 min 12 minC,DA,BE(b) Balanced for a U-shaped line2424242(12)Efficiency = = = 100 %7-54Copyright 2011 John Wiley & Sons, Inc.7-55Copyright 2011 John Wiley & Sons, Inc.All rights reserved. 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