2Chapter coverage Basic layout types Selecting a layout type Detailed design of a layout
3Layout:The layout of an operation is concerned with the physical location of its transforming resources, that is deciding where to put the facilities, machines, equipment and staff in the operation.Layout types:Fixed position layoutProcess layoutCell layoutProduct layout
4Fixed position layoutIn a fixed position layout, the transformed resource does not move between its transforming resources.Equipment, machinery, plant and people who do the processing move as necessary because the product or customer is either:Too largeToo delicate orObjects being moved
5Process layoutIn a process layout, similar processes or processes with similar needs are located together because:It is convenient to group them together orThe utilization of the transforming resource is improvedDifferent products of customer have different requirements therefore they may take different routes within the process.The flow in a process layout can be very complex.
6An example of a process layout in a library showing the path of just one customer EntranceExitOn-line and CD-ROM access roomLoan books in subject orderEnquiriesStore roomCounter staffCopying areaCompany reportsTo journal sackCurrent journalsReserve collectionReference sectionStudy desks9
7Cell layoutIn a cell layout, the transformed resources entering the operation move into a cell in which all the transforming resources it requires in located.After being processed in the cell, the transformed resource may move to a different cell in the operation or it may be a finished product or service.Each cell may be arranged in either a process or product layout.The cell type layout attempts to bring order to the complex flow seen in a process layout.
8Confectionery, newspaper, magazines and stationery The ground floor plan of a department store showing the sports goods shop-within-a-shop retail ‘cell’Sports shopMenswearWomen’s clothesLuggage and giftsConfectionery, newspaper, magazines and stationeryBooks and videosFootwearPerfume& jewelleryElevatorsEntrance9
9Product layoutIn a product layout, the transformed resource flow a long a line of processes that has been prearranged.Flow is clear, predictable and easy to control.
10An army induction centre with uses product layout Waiting areaWaiting areaLecture theatreBloodtestDoctorDoctorX-rayRecord personal history and medical detailsUniform issuing areaBloodtestDoctorDoctorX-rayBloodtestDoctorDoctorUniform storeX-ray9
11A restaurant complex with all four basic layout types Fixed-position layout service restaurantCell layout buffetLine layout cafeteriaCool roomFreezerVegetable prepGrillPreparationOvenProcess layout kitchenMain course buffetStarter buffetDesert buffetService line9
12Volume-variety relationship Fixed-position layoutProduct layoutCell layoutProcess layoutVolumeLowHighVarietyFlow is intermittentRegular flow more importantFlow becomes continuousRegular flow more feasible
13Layout selection steps Project processJobbing processBatch processMass processContinuous processProfessional servicesService shopsMass servicesFixed position layoutProcess layoutCell layoutProduct layoutThe physical position of all transforming resourcesThe flow of the operation’s transformed resourcesProcess typeBasic layout typeDetailed design of layoutVolume and varietyStrategic performance objectivesDecision 1Decision 2Decision 3
151) The nature of the basic layout types ManufacturingBasic layoutServiceprocess typestypesprocess typesProject processesProject processesFixedProfessionalposition layoutservicesJobbing processesProcess layoutService shopsBatch processesCell layoutMassprocessesMass servicesProduct layoutContinuousprocesses
162) Advantages and disadvantages FixedProcessCellProduct- Very high mix and product flexibilityposition- High mix and product flexibility- Good compromise between cost and flexibilityLo- w unit costs for high volumelayoutlayoutlayoutlayout- Product/customer not moved or disturbed.- Relatively robust if in the case of disruptions- Fast throughput.- Gives Opportunities for specialization of equipmentAdvantages- High variety of tasks for staff- Easy supervision of equipment of plant- Group work can result in good motivation- Gives Opportunities for specialization of equipmentLow utilization of resources.Can be costly to rearrange existing layoutCan have low mix and flexibility- Very high unit cost.Can have very high WIPDisadvantagesCan need more plant and equipmentNot very robust to disruption- Scheduling space and activities can be difficult.Complex flow.Work can be veryrepetitive.
17Use fixed-position or process Use process or cell or product (a) The basic layout types have different fixed and variable cost characteristics which seem to determine which one to use. (b) In practice the uncertainty about the exact fixed and variable costs of each layout means the decision can rarely be made on cost aloneUse fixed-positionUse fixed-position or processUse processUse process or cellUse process or cell or productUse cell or productUse productVolumeCostsFixed-positionProcessCellProductUsecell(a)(b)?3) Consider total cost9
19Fixed position layout design: The location of resources for each project is unique and it will be determined on the convenience of transforming resources themselves.Although there are techniques which held to locate resources on fixed position layouts, they are not widely used because this layout can be very complex and planned schedules do change frequently.
20Process layout design: When cost of traveling is important:Collecting information such as:number of loads per daycost per distance traveledWhen process relationship is importantRelationship chart
21Collecting information in process layout LOADS/DAY(a)(b)LOADS/DAYIf direction is not important, collapses to9
22Collecting information in process layout LOADS/DAY(d)LOADS/DAYABCDE30-40806020Or alternatively9
23Collecting information in process layout LOADS/DAYUNIT COST/DISTANCE TRAVELLED(f)If cost of flow differs between work centers, combine with9
24Collecting information in process layout DAILY COST/DISTANCE TRAVELLED To give9
25Collecting information in process layout (h)DAILY COST/DISTANCE TRAVELLED(i)DAILY COST/DISTANCE TRAVELLEDIf direction is not important, collapses to9
26A relationship chart DEPARTMENT Metrology E Electronic testing A I AnalysisUltrasonic testingFatigue testingEIAUOXDEPARTMENTImpact testing9
27Cell layout designCells in an operation can be created based on two interrelated decisions:What is the extent and nature of the cell i.e. the amount of direct and indirect resources the cell has as shown in Fig 7.28Which resources to allocate to which cell using:Cluster analysis – which process group naturally togetherParts and family coding – based on similar characteristics of parts of productsORProduction Flow Analysis (PFA)Examines both product requirement and process grouping(See Fig. 7.31)
28Types of cell High e.g. Specialist process Plant-within-a-plant LowCompletecomponentmanufacturing cellLunch and snackproduce area insupermarketSmall multi-machineJoint reference andcopying room in alibraryPlant-within-a-plantmanufacturingoperationMaternity unitin a hospitalSpecialist processInternal audit groupin a bankAmount of indirect resources included in the cellProportion of the resources needed to complete the transformation included in the celle.g.9
29(a) and (b) Using production flow analysis to allocate machines to cells Cell AMachinesMachinesCell BCell C9
30Product layout designProduct type layout is designed based on a technique called line balancing. The technique consist of the following steps:Calculating the required cycle time.Calculating the number of stages.Producing a precedence diagram.Finally allocating activities to the stages.
31Cycle time:It is the time between completed products emerging from the process.Example:Suppose the regional back-office operation of a large bank is designing an operation which will process its mortgage applications. The number of applications to be processed is 160 per week and the time available to process the applications is 40 hours per week.Cycle time = = 1/4 hours = 15 minutes1601 product every 15 minutes
32Number of stages Required no. of stages = total work content required cycle timeWhere the total work content is the total quantity of work involved in producing the product given in time.Example:Suppose that the bank in the previous example calculated that the average total work content of processing a mortgage application is 60 minutes. The number of stages needed to produce a processed application every 15 minutes can be calculatedRequired no. of stages = 60 minutes = 4 stages15 minutesIf you get a fraction round it up to the higher whole number.
33Precedence diagramThis is a diagram representing the ordering of the elements which comprise the total work content of the product or service.Two rules when constructing the diagram:The circles which represent the elements are drawn as far to the left as possible.None of the arrows which shows the precedence of the elements should be vertical.abcdefghi0.12 mins0.30 mins0.36 mins0.25 mins0.05 mins0.17 mins0.10 mins0.08 mins
34Allocating activities to the stages The general approach is to allocate elements from the precedence diagram to the first stage, starting from the left, until the work allocated to the stage is as close to, but less than, the cycle time.When the stage is full of work without exceeding the cycle time, move to the next stage.Two rules help to decide which activities to allocate to a stage:Choose the largest that will fit into the time remaining at the stageChoose the element with the most ‘followers’.
35Balancing lossThe effectiveness of the line balancing activity is measured by the balancing loss.This is the time wasted through the unequal allocation of work as a percentage of the total time invested in processing the product or service.Balancing loss = Total idle timeNo. of stages x Cycle time
36Balancing loss is that proportion of the time invested in processing the product or service which is not used productivelyLoadStageCycle time = 2.5 minsCycle time = 3.0 mins126.96.36.199.0An ideal ‘balance’ where work is allocated equally between the stagesBut if work is not equally allocated the cycle time will increase and ‘balancing losses’ will occurWork allocated to stageIdle timeCalculating balancing loss:Idle time every cycle =( ) +( ) +( ) = 2.0 minsBalancing loss = 24 x 3.0== 16.67%9
37Worked ExampleConsider Karlstad Kakes, a manufacturer of specialty cakes, which has recently obtained contract to supply a major supermarket chain with a specialty cake in the shape of a space rocket. It has been decided that the volumes required by the supermarket warrant a special production line to perform the finishing, decorating and packing of the cake. This line would have to carry out the elements shown in the next slide, which also shows the precedence diagram for the total job. The initial order from the supermarket is for 5000 cakes a week and the number of hours worked by the factory is 40 per week. From this:The required cycle time = 40 hrs x 60 mins = 0.48 mins5000The required number of stages = 1.68 mins (total work content)0.48 mins (required cycle time)= 3.5 stages
38Element listing and precedence diagram for Karlstad Kates Element De-tin and trim minsaElement Reshape with off-cuts minsbElement Clad in almond fondant minscElement Clad in white fondant minsdElement Decorate, red icing minseElement Decorate, green icing minsfElement Decorate, blue icing minsgElement Affix transfers minshElement Transfer to base and pack minsiTotal work content = 1.68 mins0.12 mins0.30 mins0.36 mins0.25 mins0.05 mins0.17 mins0.10 mins0.08 mins9
39Allocation of elements to stages and balancing loss for Karlstad Kates hi0.12 mins0.30 mins0.36 mins0.25 mins0.05 mins0.17 mins0.10 mins0.08 minsStage 1Stage 2Stage 3Stage 4Cycle time = 0.48 minsIdle time every cycle = ( ) + ( ) + ( ) = 0.24 minsProportion of idle time per cycle = = 12.5%4 x 0.489