5275401 (2).ppt
- 1. © Wiley 2010 1 Chapter 10 – Facility Layout Operations Management by R. Dan Reid & Nada R. Sanders 4th Edition © Wiley 2010
- 2. © Wiley 2010 2 Learning Objectives Define layout planning and explain its importance Identify and describe different types of layouts Compare process layouts & product layouts Describe the steps involved in designing a process layout Describe the steps involved in designing a product layout Explain the advantages of hybrid layouts Define the meaning of group technology (cell) layouts
- 3. © Wiley 2010 3 Layout Planning Layout planning is deciding the best physical arrangement of all resources that consumes space within a facility Facility resource arrangement can significantly affect productivity and quality of products/services Two broad categories of operations: Intermittent processing systems – low volume of many different products Continuous processing systems – high volume of a few standardized products
- 4. © Wiley 2010 4 Types of Layouts Four basic layout types consisting of: Fixed-Position layouts - Product is too large to move; e.g. a building Process layouts - Group similar resources together Product layouts - arrange activities according to sequence of operations for a particular product/service Hybrid layouts - Combine aspects of both process and product layouts
- 5. © Wiley 2010 5 5 Underlying Process Relationship Between Volume and Standardization Continuum
- 6. © Wiley 2010 6 Fixed-Position Layout Used when product is large Product is difficult or impossible to move, i.e. very large or fixed All resources must be brought to the site Scheduling of crews and resources is a challenge
- 7. © Wiley 2010 7 Process Layout in Services Women’s lingerie Women’s dresses Women’s sportswear Shoes Cosmetics and jewelry Entry and display area Housewares Children’s department Men’s department
- 8. © Wiley 2010 8 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 A A Receiving and Shipping Assembly Painting Department Lathe Department Milling Department Drilling Department Grinding Department P P
- 9. © Wiley 2010 9 A Product Layout In Out
- 10. © Wiley 2010 10 Process vs. Product Layouts Here are the characteristic differences between a process and product layout.
- 11. © Wiley 2010 11 Hybrid Layouts Combine elements of both product & process layouts Maintain some of the efficiencies of product layouts Maintain some of the flexibility of process layouts Examples: Group technology & manufacturing cells Grocery stores
- 12. © Wiley 2010 12 Original Process Layout C A B Raw materials Assembly 1 2 3 4 5 6 7 8 9 10 11 12
- 13. © Wiley 2010 13 Revised Cellular Layout 3 6 9 Assembly 1 2 4 8 10 5 7 11 12 A C B Raw materials Cell 1 Cell 2 Cell 3
- 14. © Wiley 2010 14 Designing Process Layouts Step 1: Gather information: Space needed, space available, identify closeness measures Step 2: Develop alternative block plans: Using trial-and-error or decision support tools Step 3: Develop a detailed layout: Consider exact sizes/shapes of departments and work centers including aisles and stairways Tools like drawings, 3-D models, and CAD software are available to facilitate this process
- 15. © Wiley 2010 15 Computerized layout Solutions CRAFT Computerized Relative Allocation of Facilities Technique CORELAP Computerized Relationship Layout Planning PROMODEL and EXTEND visual feedback allow user to quickly test a variety of scenarios Three-D modeling and CAD integrated layout analysis available in VisFactory and similar software
- 16. © Wiley 2010 16 Designing Service Layouts Must be both attractive and functional Types Free flow layouts encourage browsing, increase impulse purchasing, are flexible and visually appealing Grid layouts encourage customer familiarity, are low cost, easy to clean and secure, and good for repeat customers Loop and Spine layouts both increase customer sightlines and exposure to products, while encouraging customer to circulate through the entire store
- 17. © Wiley 2010 17 Types of Store Layouts
- 18. © Wiley 2010 18 Designing Product Layouts Designing product layouts requires consideration of sequence of tasks to be performed by each workstation in a logical order Goal: Maximize production capacity, i.e., the line must be as balanced as possible
- 19. © Wiley 2010 19 Flow Time vs Cycle Time Cycle time = max time spent at any station Flow time = time to complete all stations 1 2 3 4 minutes 4 minutes 4 minutes Flow time = 4 + 4 + 4 = 12 minutes Cycle time = max (4, 4, 4) = 4 minutes
- 20. © Wiley 2010 20 Designing Product Layouts – con’t Step 1: Identify tasks & immediate predecessors Step 2: Determine output rate Step 3: Determine cycle time Step 4: Compute the Theoretical Minimum number of Stations Step 5: Assign tasks to workstations (balance the line) Step 6: Compute efficiency, idle time & balance delay
- 21. © Wiley 2010 21 Step 1: Identify Tasks & Immediate Predecessors Example 10.4 Vicki's Pizzeria and the Precedence Diagram Immediate Task Time Work Element Task Description Predecessor (seconds A Roll dough None 50 B Place on cardboard backing A 5 C Sprinkle cheese B 25 D Spread Sauce C 15 E Add pepperoni D 12 F Add sausage D 10 G Add mushrooms D 15 H Shrinkwrap pizza E,F,G 18 I Pack in box H 15 Total task time 165
- 22. © Wiley 2010 22 Layout Calculations Step 2: Determine output rate Vicki needs to produce 60 pizzas per hour Step 3: Determine cycle time The amount of time each workstation is allowed to complete its tasks Limited by the bottleneck task (the longest task in a process): sec./unit 60 units/hr 60 sec/min 60 x min/hr 60 units/hr output desired sec./day time available ) (sec./unit time Cycle hour per pizzas or units/hr, 72 sec./unit 50 sec./hr. 3600 time task bottleneck time available output Maximum
- 23. © Wiley 2010 23 Layout Calculations (continued) Step 4: Compute the theoretical minimum number of stations TM = number of stations needed to achieve 100% efficiency (every second is used) Always round up (no partial workstations) Serves as a lower bound for our analysis stations 3 or 2.75, n sec/statio 60 seconds 165 time cycle times task TM
- 24. © Wiley 2010 24 Layout Calculations (continued) Step 5: Assign tasks to workstations Start at the first station & choose the longest eligible task following precedence relationships Continue adding the longest eligible task that fits without going over the desired cycle time When no additional tasks can be added within the desired cycle time, begin assigning tasks to the next workstation until finished Workstation Eligible task Task Selected Task time Idle time A A 50 10 B B 5 5 C C 25 35 D D 15 20 E, F, G G 15 5 E, F E 12 48 F F 10 38 H H 18 20 I I 15 5 1 2 3
- 25. © Wiley 2010 25 Layout Calculations (Continued) Step 6: Compute efficiency and balance delay Efficiency (%) is the ratio of total productive time divided by total time Balance delay (%) is the amount by which the line falls short of 100% 91.7% 100 sec. 60 x stations 3 sec. 165 NC t (%) Efficiency 8.3% 91.7% 100% delay Balance
- 26. © Wiley 2010 26 Other Product Layout Considerations Shape of the line (S, U, O, L): Share resources, enhance communication & visibility, impact location of loading & unloading Paced versus unpaced lines Paced lines use an automatically enforced cycle time Number of Product Models produced Single Mixed-model lines
- 27. © Wiley 2010 27 Group Technology (CELL) Layouts One of the most popular hybrid layouts uses Group Technology (GT) and a cellular layout GT has the advantage of bringing the efficiencies of a product layout to a process layout environment
- 28. © Wiley 2010 28 Process Flows before the Use of GT Cells
- 29. © Wiley 2010 29 Process Flows after the Use of GT Cells
- 30. © Wiley 2010 30 Chapter 10 Highlights Layout planning is deciding on the best physical arrangement of all resources within a facility. There are four basic types of layouts: process, product, hybrid, and fixed position. Process layouts provide more flexibility while product layouts provide greater efficiency. The steps for designing process layouts are (1) gather information about space needs, space availability, and closeness requirements of departments; (2) developing a block plan or schematic of the layout; and (3) developing a detailed layout. The steps for designing an product layout are (1) identify tasks that need to be performed and their immediate predecessors; (2) determine output rate; (3) determine cycle time; (4) computing the theoretical minimum number of work stations, (5) assigning tasks to workstations; and (6) computing efficiency and balance delay. Hybrids layouts (e.g., group technology or cell layouts) combine elements of both process and product layouts to increase efficiency. Group technology first groups products based on similar processing requirements. Cells are created for each grouping of products, resulting in a more orderly flow of products through the facility.