3 Introduction Process selection Major implications Deciding on the way production of goods or services will be organizedMajor implicationsCapacity planningLayout of facilitiesEquipmentDesign of work systems
4 Process Selection and System Design Figure 6.1ForecastingProduct and Service DesignTechnological ChangeCapacity PlanningProcess SelectionFacilities and EquipmentLayoutWork Design
5 Process Strategy Key aspects of process strategy Capital intensive – equipment/laborProcess flexibilityAdjust to changesDesignVolumetechnology
6 Process Selection Variety Flexibility Volume How much What degree Expected outputBatchJob ShopRepetitiveContinuous
7 Process Types Job shop Batch Repetitive/assembly line Continuous Small scaleBatchModerate volumeRepetitive/assembly lineHigh volumes of standardized goods or servicesContinuousVery high volumes of non-discrete goods
17 Basic Layout Types Product layout Process layout Fixed Position layout Layout that uses standardized processing operations to achieve smooth, rapid, high-volume flowProcess layoutLayout that can handle varied processing requirementsFixed Position layoutLayout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed
18 Product Layout Figure 6.4 Raw materials or customer Station1Station2Station3Station4Finished itemMaterialand/or laborMaterialand/or laborMaterialand/or laborMaterialand/or laborUsed for Repetitive or Continuous Processing
19 Advantages of Product Layout High rate of outputLow unit costLabor specializationLow material handling costHigh utilization of labor and equipmentEstablished routing and schedulingRouting accounting and purchasing
20 Disadvantages of Product Layout Creates dull, repetitive jobsPoorly skilled workers may not maintain equipment or quality of outputFairly inflexible to changes in volumeHighly susceptible to shutdownsNeeds preventive maintenanceIndividual incentive plans are impractical
21 A U-Shaped Production Line Figure 6.612345678910InOutWorkers
22 Used for Intermittent processing Process LayoutFigure 6.7Process Layout(functional)Dept. ADept. BDept. DDept. CDept. FDept. EUsed for Intermittent processingJob Shop or Batch
23 Used for Repetitive Processing Repetitive or Continuous Product LayoutFigure 6.7 (cont’d)Product Layout(sequential)WorkStation 1Station 2Station 3Used for Repetitive ProcessingRepetitive or Continuous
24 Advantages of Process Layouts Can handle a variety of processing requirementsNot particularly vulnerable to equipment failuresEquipment used is less costlyPossible to use individual incentive plans
25 Disadvantages of Process Layouts In-process inventory costs can be highChallenging routing and schedulingEquipment utilization rates are lowMaterial handling slow and inefficientComplexities often reduce span of supervisionSpecial attention for each product or customerAccounting and purchasing are more involved
26 Cellular Layouts Cellular Production Group Technology Layout in which machines are grouped into a cell that can process items that have similar processing requirementsGroup TechnologyThe grouping into part families of items with similar design or manufacturing characteristics
27 Functional vs. Cellular Layouts Table 6.3DimensionFunctionalCellularNumber of moves between departmentsmanyfewTravel distanceslongershorterTravel pathsvariablefixedJob waiting timesgreaterThroughput timehigherlowerAmount of work in processSupervision difficultyScheduling complexityEquipment utilization
28 Other Service Layouts Warehouse and storage layouts Retail layouts Office layouts
29 Design Product Layouts: Line Balancing Line Balancing is the process of assigningtasks to workstations in such a way that the workstations have approximately equal time requirements.
30 Cycle Time Cycle time is the maximum time allowed at each workstation tocomplete its set of tasks on a unit.
32 Determine the Minimum Number of Workstations Required
33 Precedence Diagram a b c d e Figure 6.10Precedence diagram: Tool used in line balancing to display elemental tasks and sequence requirementsA Simple PrecedenceDiagramabcde0.1 min.0.7 min.1.0 min.0.5 min.0.2 min.
34 Example 1: Assembly Line Balancing Arrange tasks shown in Figure 6.10 into three workstations.Use a cycle time of 1.0 minuteAssign tasks in order of the most number of followers
35 Example 1 Solution Workstation Time Remaining Eligible Assign Task Revised Time RemainingStation Idle Time11.00.90.2a, ccnonea-2b0.030.50.3de
36 Calculate Percent Idle Time Efficiency = 1 – Percent idle time
37 Some Heuristic (intuitive) Rules: Line Balancing RulesSome Heuristic (intuitive) Rules:Assign tasks in order of most following tasks.Count the number of tasks that followAssign tasks in order of greatest positional weight.Positional weight is the sum of each task’s time and the times of all following tasks.
41 Designing Process Layouts Information Requirements:List of departmentsProjection of work flowsDistance between locationsAmount of money to be investedList of special considerationsLocation of key utilities
42 Example 3: Interdepartmental Work Flows for Assigned Departments Figure 6.1213230170100ABC
43 Author’s note:The following three slides are not in the 8e, but I like to use them for alternate examples.
44 Process Layout - work travels to dedicated process centers MillingAssembly & TestGrindingDrillingPlating