Chapter 9 Facility Layout

Objectives of Facility Layout Minimize material handling costs Utilize space efficiently Utilize labor efficiently Eliminate bottlenecks Facilitate communication and interaction between workers, between workers and their supervisors, or between workers and customers Reduce manufacturing cycle time or customer service time

Objectives of Facility Layout Eliminate waste or redundant movement Facilitate the entry, exit, and placement of material, products, or people Incorporate safety and security measures Promote product and service quality Encourage proper maintenance activities Provide a visual control of operations or activities Provide flexibility to adapt to changing conditions Increase capacity

Process Layout Machines grouped by process they perform Product Layout Linear arrangement of workstations to produce a specific product Fixed Position Layout Used in projects where the product cannot be moved Basic Types of Layouts

Manufacturing Process Layout L L L L L L L L L L M M M M D D D D D D D D G G G G G G A AA Receiving and Shipping Assembly Painting Department Lathe Department Milling Department Drilling Department Grinding Department P P

A Product Layout In Out

Comparison Of Product And Process Layouts 1.DescriptionSequential arrangementFunctional grouping of machines of machines of machines of machines 2.Type of ProcessContinuous, mass Intermittent, job shop production, mainly batch production, production, mainly batch production, assembly mainly fabrication assembly mainly fabrication 3.ProductStandardizedVaried, made to stock made to order made to stock made to order 4.DemandStableFluctuating 5.VolumeHighLow 6.EquipmentSpecial purposeGeneral purpose 7.WorkersLimited skillsVaried skills PRODUCT LAYOUTPROCESS LAYOUT

Comparison Of Product And Process Layouts 8. InventoryLow in-process,High in-process, 8. InventoryLow in-process,High in-process, high finished goods low finished goods high finished goods low finished goods 9. Storage spaceSmallLarge 9. Storage spaceSmallLarge 10. MaterialFixed pathVariable path handling (conveyor) (forklift) handling (conveyor) (forklift) 11. AislesNarrowWide 12. SchedulingPart of balancingDynamic 13. Layout decisionLine balancingMachine location 14. GoalEqualize work atMinimize material each station handling cost each station handling cost 15. AdvantageEfficiencyFlexibility PRODUCT LAYOUTPROCESS LAYOUT

Fixed-Position Layouts Typical of projects Equipment, workers, materials, other resources brought to the site Highly skilled labor Often low fixed costs Typically high variable costs

Line Balancing Precedence diagram Precedence diagram Network showing order of tasks and restrictions on their performance Network showing order of tasks and restrictions on their performance Cycle time Cycle time Maximum time product spends at any one workstation Maximum time product spends at any one workstation

Line Balancing Precedence diagram Precedence diagram Network showing order of tasks and restrictions on their performance Network showing order of tasks and restrictions on their performance Cycle time Cycle time Maximum time product spends at any one workstation Maximum time product spends at any one workstation C d = production time available desired units of output Cycle time example C d = (8 hours x 60 minutes / hour) (120 units) C d = = 4 minutes

Flow Time vs Cycle Time Cycle time = max time spent at any station Flow time = time to complete all stations

Flow Time vs Cycle Time Cycle time = max time spent at any station Flow time = time to complete all stations minutes 3 minutes 4 minutes Flow time = = 12 minutes Cycle time = max (4, 3, 4) = 4 minutes

Line Balancing WORK ELEMENTPRECEDENCETIME (MIN) APress out sheet of fruit—0.1 BCut into stripsA0.2 COutline fun shapesA0.4 DRoll up and packageB, C0.3

Line Balancing WORK ELEMENTPRECEDENCETIME (MIN) APress out sheet of fruit—0.1 BCut into stripsA0.2 COutline fun shapesA0.4 DRoll up and packageB, C D B C A Example 5.2

Line Balancing WORK ELEMENTPRECEDENCETIME (MIN) APress out sheet of fruit—0.1 BCut into stripsA0.2 COutline fun shapesA0.4 DRoll up and packageB, C D B C A Example 5.2 C d = = = 0.4 minute 40 hours x 60 minutes / hour 6,000 units N = = = 2.5 workstations

Line Balancing WORK ELEMENTPRECEDENCETIME (MIN) APress out sheet of fruit—0.1 BCut into stripsA0.2 COutline fun shapesA0.4 DRoll up and packageB, C D B C A Example 5.2 C d = = = 0.4 minute 40 hours x 60 minutes / hour 6,000 units N = = = 2.5 workstations workstations

Line Balancing WORK ELEMENTPRECEDENCETIME (MIN) APress out sheet of fruit—0.1 BCut into stripsA0.2 COutline fun shapesA0.4 DRoll up and packageB, C D B C A C d = 0.4 N = 2.5

Line Balancing D B C A C d = 0.4 N = 2.5

Line Balancing D B C A C d = 0.4 N = 2.5

Line Balancing D B C A C d = 0.4 N = 2.5

Line Balancing D B C A C d = 0.4 N = 2.5 A, B C D Work station 1 Work station 2 Work station minute 0.4 minute 0.3 minute

Efficiency of Line  i i = 1 titititi nC a E =E =E =E =  i i = 1 titititi CdCdCdCd N =N =N =N = Efficiency Minimum number of workstations where t i = completion time for element i j = number of work elements n = actual number of workstations C a = actual cycle time C d = desired cycle time

Line Balancing D B C A C d = 0.4 N = 2.5 A, B C D Work station 1 Work station 2 Work station minute 0.4 minute 0.3 minute E = = = = 83.3% (0.4)

Line Balancing Process 1. Draw and label a precedence diagram. 2. Calculate the desired cycle time required for the line. 3. Calculate the theoretical minimum number of workstations. 4. Group elements into workstations, recognizing cycle time and precedence constraints. 5. Calculate the efficiency of the line. 6. Stop if theoretical minimum number of workstations or an acceptable efficiency level reached. If not, go back to step 4.

1.Construct a “from-to matrix” 2.Determine the space requirements 3.Develop an initial schematic diagram 4.Determine the cost of this layout 5.Try to improve the layout 6.Prepare a detailed plan Arrange six departments in a factory to minimize the material handling costs. Each department is 20 x 20 feet and the building is 60 feet long and 40 feet wide. Process Layout Example

DepartmentAssemblyPaintingMachineReceivingShippingTesting (1)(2)Shop (3)(4)(5)(6) Assembly (1) Painting (2) Machine Shop (3) Receiving (4) Shipping (5) Testing (6) Number of loads per week Figure 9.4 Process Layout Example

Room 1Room 2Room 3 Room 4Room 5Room 6 60’ 40’ ReceivingShippingTesting DepartmentDepartmentDepartment (4)(5)(6) Figure 9.5 AssemblyPaintingMachine Shop DepartmentDepartmentDepartment (1)(2)(3) Process Layout Example

Cost =$50+$200+$40 (1 and 2)(1 and 3)(1 and 6) +$30+$50+$10 (2 and 3)(2 and 4)(2 and 5) +$40+$100+$50 (3 and 4)(3 and 6)(4 and 5) = $570 Cost = ∑ ∑ X ij C ij n i = 1 n j = 1 Process Layout Example

Interdepartmental Flow Graph Figure 9.6 Process Layout Example

Cost =$50+$100+$20 (1 and 2)(1 and 3)(1 and 6) +$60+$50+$10 (2 and 3)(2 and 4)(2 and 5) +$40+$100+$50 (3 and 4)(3 and 6)(4 and 5) = $480 Cost = ∑ ∑ X ij C ij n i = 1 n j = 1 Process Layout Example

Interdepartmental Flow Graph Figure 9.7 Process Layout Example

Room 1Room 2Room 3 Room 4Room 5Room 6 60’ 40’ ReceivingShippingTesting DepartmentDepartmentDepartment (4)(5)(6) Figure 9.8 Painting Assembly Machine Shop DepartmentDepartmentDepartment (2)(1)(3) Process Layout Example

Using Excel OM Use Operations Layout MacroUse Operations Layout Macro # of departments should be # of rooms# of departments should be # of rooms Input flows as givenInput flows as given Make sure distance table is symmetricMake sure distance table is symmetric To model adjacency, put a distance of 1 for non-adjacent departments, 0 for adjacent departmentsTo model adjacency, put a distance of 1 for non-adjacent departments, 0 for adjacent departments Or use regular distanceOr use regular distance

Relationship Diagramming Used when quantitative data is not available Muther’s grid displays preferences Denote location preferences with weighted lines

Relationship Diagramming Example Production Offices Stockroom Shipping and receiving Locker room Toolroom

Relationship Diagramming Example A A A O O O O O U U U U E X I Production Offices Stockroom Shipping and receiving Locker room Toolroom AAbsolutely necessary EEspecially important IImportant OOkay UUnimportant XUndesirable

Relationship Diagrams Offices Stockroom Locker room Toolroom Shipping and receiving Production (a) Relationship diagram of original layout Figure 5.6 Key:A EIOUX

Relationship Diagrams Figure 5.6 (b) Relationship diagram of revised layout Offices Stockroom Locker room Toolroom Shipping and receiving Production Key:A EIOUX

Using Excel OM Operations Layout Macro can be used for Relationship Diagrams tooOperations Layout Macro can be used for Relationship Diagrams too Make distance table like beforeMake distance table like before For flows table, use dummy flows:For flows table, use dummy flows: –A = 100,000O = 100 –E = 10,000U = 10 –I = 1,000X = 0