Reid & Sanders, Operations Management © Wiley 2002 Facility Layout 10 C H A P T E R

Reid & Sanders, Operations Management © Wiley 2002 Page 2 Learning Objectives Define facility layout Describe different types of layouts Compare process & product layouts Describe the design process for different layouts Explain the advantages of hybrid layouts Define group technology & manufacturing cells

Reid & Sanders, Operations Management © Wiley 2002 Page 3 Facility Layout Layout planning is determining the best physical arrangement of resources within a facility Process layouts: –Group similar resources together –Emphasis is on flexibility Product layouts: –Designed to produce a specific product efficiently –Emphasis is on efficiency

Reid & Sanders, Operations Management © Wiley 2002 Page 4 Process Layouts General purpose & flexible resources Lower capital intensity & automation Higher labor intensity Processing rates are slower Material handling costs are higher Scheduling resources & work flow is more complex

Reid & Sanders, Operations Management © Wiley 2002 Page 5 Product Layouts Specialized equipment High capital intensity & wide use of automation Processing rates are faster Material handling costs are lower Less space required for inventories Less volume or design flexibility

Reid & Sanders, Operations Management © Wiley 2002 Page 6 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 Example: group technology & manufacturing cells

Reid & Sanders, Operations Management © Wiley 2002 Page 7 Group Technology

Reid & Sanders, Operations Management © Wiley 2002 Page 8 Traditional Process Layout

Reid & Sanders, Operations Management © Wiley 2002 Page 9 Manufacturing Cells

Reid & Sanders, Operations Management © Wiley 2002 Page 10 Designing Process Layouts Gather information: –Space needed, space available, importance of proximity between various units Develop alternative block plans: –Using trail-and-error or decision support tools Compare alternatives & choose a detailed layout:

Reid & Sanders, Operations Management © Wiley 2002 Page 11 Comparing Alternatives Load-distance measures –Load: # of trips, weight moved, $-value moved –Distance: rectilinear distance (using north-south & east-west movements) REL charts: –Management opinion on strength of relationships Software tools: –CRAFT: computerized relative allocation of facilities technique –ALDEP: automated layout design program

Reid & Sanders, Operations Management © Wiley 2002 Page 12 Designing Product Layouts Identify tasks & immediate predecessors Determine the desired output rate Calculate the necessary cycle time Compute the theoretical minimum number of workstations Assign tasks to workstations Compute efficiency, idle time & balance delay

Reid & Sanders, Operations Management © Wiley 2002 Page 13 Cycle Time The amount of time each workstation is allowed to complete its tasks Limited by the bottleneck task (the longest task to be performed):

Reid & Sanders, Operations Management © Wiley 2002 Page 14 Theoretical Minimum Number of Workstations 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

Reid & Sanders, Operations Management © Wiley 2002 Page 15 Assigning Tasks to Workstations Start at the first station & choose the longest eligible task (tasks with no unassigned predecessors) Continue adding the longest eligible task that fits without going over the desired cycle time When no additional tasks can be added, begin assigning tasks to the next workstation Continue until all tasks are assigned

Reid & Sanders, Operations Management © Wiley 2002 Page 16 Compute Efficiency & Balance Delay Efficiency is the ratio of productive time to total time: Balance delay:

Reid & Sanders, Operations Management © Wiley 2002 Page 17 Frozen Pizza Example Desired output is 60 pizzas/hour –Cycle time is (3600 seconds/hour)/(60 units/hour) –Cycle time = 60 seconds/unit

Reid & Sanders, Operations Management © Wiley 2002 Page 18 Assign Tasks

Reid & Sanders, Operations Management © Wiley 2002 Page 19 Compute Efficiency

Reid & Sanders, Operations Management © Wiley 2002 Page 20 Other 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 Single or mixed-model lines

Reid & Sanders, Operations Management © Wiley 2002 Page 21 The End Copyright © 2002 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United State Copyright Act without the express written permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information contained herein.