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Chapter 9

Chapter 9. Facility Layout. Objectives of Facility Layout. Minimize material handling costs Utilize space efficiently Utilize labor efficiently Eliminate bottlenecks

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Chapter 9

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  1. Chapter 9 Facility Layout

  2. 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

  3. 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

  4. Basic Types of Layouts 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

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

  6. In Out A Product Layout

  7. PRODUCT LAYOUT PROCESS LAYOUT Comparison Of Product And Process Layouts 1. Description Sequential arrangement Functional grouping of machines of machines 2. Type of Process Continuous, mass Intermittent, job shop production, mainly batch production, assembly mainly fabrication 3. Product Standardized Varied, made to stock made to order 4. Demand Stable Fluctuating 5. Volume High Low 6. Equipment Special purpose General purpose 7. Workers Limited skills Varied skills

  8. PRODUCT LAYOUT PROCESS LAYOUT Comparison Of Product And Process Layouts 8. Inventory Low in-process, High in-process, high finished goods low finished goods 9. Storage space Small Large 10. Material Fixed path Variable path handling (conveyor) (forklift) 11. Aisles Narrow Wide 12. Scheduling Part of balancing Dynamic 13. Layout decision Line balancing Machine location 14. Goal Equalize work at Minimize material each station handling cost 15. Advantage Efficiency Flexibility

  9. 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

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

  11. production time available desired units of output Cd = (8 hours x 60 minutes / hour) (120 units) Cd = 480 120 Cd= = 4 minutes Line Balancing Cycle time example • Precedence diagram • Network showing order of tasks and restrictions on their performance • Cycle time • Maximum time product spends at any one workstation

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

  13. 1 2 3 4 minutes 3 minutes 4 minutes Flow Time vs Cycle Time Cycle time = max time spent at any station Flow time = time to complete all stations Flow time = 4 + 4 + 4 = 12 minutes Cycle time = max (4, 3, 4) = 4 minutes

  14. WORK ELEMENT PRECEDENCE TIME (MIN) A Press out sheet of fruit — 0.1 B Cut into strips A 0.2 C Outline fun shapes A 0.4 D Roll up and package B, C 0.3 Line Balancing

  15. WORK ELEMENT PRECEDENCE TIME (MIN) A Press out sheet of fruit — 0.1 B Cut into strips A 0.2 C Outline fun shapes A 0.4 D Roll up and package B, C 0.3 0.2 B A 0.3 0.1 D C 0.4 Line Balancing Example 5.2

  16. WORK ELEMENT PRECEDENCE TIME (MIN) A Press out sheet of fruit — 0.1 B Cut into strips A 0.2 C Outline fun shapes A 0.4 D Roll up and package B, C 0.3 0.2 0.1 + 0.2 + 0.3 + 0.4 0.4 B 2400 6000 40 hours x 60 minutes / hour 6,000 units Cd = = = 0.4 minute A 0.3 0.1 D 1.0 0.4 N = = = 2.5 workstations C 0.4 Line Balancing Example 5.2

  17. WORK ELEMENT PRECEDENCE TIME (MIN) A Press out sheet of fruit — 0.1 B Cut into strips A 0.2 C Outline fun shapes A 0.4 D Roll up and package B, C 0.3 0.2 0.1 + 0.2 + 0.3 + 0.4 0.4 B 2400 6000 40 hours x 60 minutes / hour 6,000 units Cd = = = 0.4 minute A 0.3 0.1 D 1.0 0.4 N = = = 2.5 workstations C 0.4 Line Balancing 3 workstations Example 5.2

  18. WORK ELEMENT PRECEDENCE TIME (MIN) A Press out sheet of fruit — 0.1 B Cut into strips A 0.2 C Outline fun shapes A 0.4 D Roll up and package B, C 0.3 0.2 B A 0.3 0.1 D C 0.4 Line Balancing Cd = 0.4 N = 2.5

  19. 0.2 B A 0.3 0.1 D C 0.4 Line Balancing Cd = 0.4 N = 2.5

  20. 0.2 B A 0.3 0.1 D C 0.4 Line Balancing Cd = 0.4 N = 2.5

  21. 0.2 B A 0.3 0.1 D C 0.4 Line Balancing Cd = 0.4 N = 2.5

  22. Work station 1 Work station 2 Work station 3 0.3 minute 0.4 minute 0.3 minute 0.2 B A, B A 0.3 0.1 D D C C 0.4 Line Balancing Cd = 0.4 N = 2.5

  23. Minimum number of workstations Efficiency i i= 1 i i= 1   ti ti N = E = nCa Cd Efficiency of Line where ti = completion time for element i j = number of work elements n = actual number of workstations Ca = actual cycle time Cd = desired cycle time

  24. Work station 1 Work station 2 Work station 3 0.3 minute 0.4 minute 0.3 minute 0.2 0.1 + 0.2 + 0.3 + 0.4 3(0.4) B A, B 1.0 1.2 A 0.3 0.1 D E = = = 0.833 = 83.3% D C C 0.4 Line Balancing Cd = 0.4 N = 2.5

  25. 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.

  26. Process Layout Example 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. Construct a “from-to matrix” Determine the space requirements Develop an initial schematic diagram Determine the cost of this layout Try to improve the layout Prepare a detailed plan

  27. Number of loads per week Department Assembly Painting Machine Receiving Shipping Testing (1) (2) Shop (3) (4) (5) (6) Assembly (1) Painting (2) Machine Shop (3) Receiving (4) Shipping (5) Testing (6) Process Layout Example 50 100 0 0 20 30 50 10 0 20 0 100 50 0 0 Figure 9.4

  28. Room 1 Room 2 Room 3 Room 4 Room 5 Room 6 40’ 60’ Process Layout Example Assembly Painting Machine Shop Department Department Department (1) (2) (3) Receiving Shipping Testing Department Department Department (4) (5) (6) Figure 9.5

  29. n i = 1 n j = 1 Cost = ∑ ∑ Xij Cij 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

  30. 100 50 30 1 2 3 20 20 10 50 100 4 5 6 50 Process Layout Example Interdepartmental Flow Graph Figure 9.6

  31. n i = 1 n j = 1 Cost = ∑ ∑ Xij Cij 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

  32. 30 50 100 2 1 3 10 20 50 100 50 50 4 5 6 Process Layout Example Interdepartmental Flow Graph Figure 9.7

  33. Room 1 Room 2 Room 3 Room 4 Room 5 Room 6 40’ 60’ Process Layout Example Painting Assembly Machine Shop Department Department Department (2) (1) (3) Receiving Shipping Testing Department Department Department (4) (5) (6) Figure 9.8

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

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

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

  37. Production O A Offices U I E O Stockroom A A X Shipping and receiving U U U O O Locker room O Toolroom Relationship Diagramming Example A Absolutely necessary E Especially important I Important O Okay U Unimportant X Undesirable

  38. Offices Locker room Shipping and receiving Key: A E I O U X Stockroom Toolroom Production Relationship Diagrams (a) Relationship diagram of original layout Figure 5.6

  39. Stockroom Offices Shipping and receiving Key: A E I O U X Toolroom Production Locker room Relationship Diagrams (b) Relationship diagram of revised layout Figure 5.6

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

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