6-1Process Selection and Facility Layout William J. Stevenson Operations Management 8 th edition

6-2Process Selection and Facility Layout CHAPTER 6 Process Selection and Facility Layout McGraw-Hill/Irwin Operations Management, Eighth Edition, by William J. Stevenson Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved.

6-3Process Selection and Facility Layout  Process selection  Deciding on the way production of goods or services will be organized  Major implications  Capacity planning  Layout of facilities  Equipment  Design of work systems Introduction

6-4Process Selection and Facility Layout Key aspects of process strategy – Capital intensive – equipment/labor – Process flexibility – Adjust to changes – Design – Volume – technology Process Strategy

6-5Process Selection and Facility Layout  Variety  How much  Flexibility  What degree  Volume  Expected output Job Shop Batch Repetitive Continuous Process Selection

6-6Process Selection and Facility Layout  Job shop  Small scale  Batch  Moderate volume  Repetitive/assembly line  High volumes of standardized goods or services  Continuous  Very high volumes of non-discrete goods Process Types

6-7Process Selection and Facility Layout Flexible Manufacturing VD7 Process at Trek Bikes

6-8Process Selection and Facility Layout Process Overview AB2 Aluminum tubing, suppliers at Hillerich & Bradsby

6-9Process Selection and Facility Layout Process Type Job Shop Appliance repair Emergency room Not feasible Batch Commercial bakery Classroom Lecture Repetitive Automotive assembly Automatic carwash Continuous (flow) Not feasible Oil refinery Water purification Figure 6.2 Product – Process Matrix

6-10Process Selection and Facility Layout  Automation: Machinery that has sensing and control devices that enables it to operate  Fixed automation  Programmable automation Automation

6-11Process Selection and Facility Layout Computer-aided design and manufacturing systems (CAD/CAM) Numerically controlled (NC) machines Robot Manufacturing cell Flexible manufacturing systems(FMS) Computer-integrated manufacturing (CIM) Automation

6-12Process Selection and Facility Layout  Layout: the configuration of departments, work centers, and equipment, with particular emphasis on movement of work (customers or materials) through the system Facilities Layout

6-13Process Selection and Facility Layout  Requires substantial investments of money and effort  Involves long-term commitments  Has significant impact on cost and efficiency of short-term operations Importance of Layout Decisions

6-14Process Selection and Facility Layout Inefficient operations For Example: High Cost Bottlenecks Changes in the design of products or services The introduction of new products or services Accidents Safety hazards The Need for Layout Decisions

6-15Process Selection and Facility Layout Changes in environmental or other legal requirements Changes in volume of output or mix of products Changes in methods and equipment Morale problems The Need for Layout Design (Cont’d)

6-16Process Selection and Facility Layout  Product layouts  Process layouts  Fixed-Position layout  Combination layouts Basic Layout Types

6-17Process Selection and Facility Layout  Product layout  Layout that uses standardized processing operations to achieve smooth, rapid, high- volume flow  Process layout  Layout that can handle varied processing requirements  Fixed Position layout  Layout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed Basic Layout Types

6-18Process Selection and Facility Layout Raw materials or customer Finished item Station 2 Station 2 Station 3 Station 3 Station 4 Station 4 Material and/or labor Station 1 Material and/or labor Material and/or labor Material and/or labor Used for Repetitive or Continuous Processing Figure 6.4 Product Layout

6-19Process Selection and Facility Layout  High rate of output  Low unit cost  Labor specialization  Low material handling cost  High utilization of labor and equipment  Established routing and scheduling  Routing accounting and purchasing Advantages of Product Layout

6-20Process Selection and Facility Layout  Creates dull, repetitive jobs  Poorly skilled workers may not maintain equipment or quality of output  Fairly inflexible to changes in volume  Highly susceptible to shutdowns  Needs preventive maintenance  Individual incentive plans are impractical Disadvantages of Product Layout

6-21Process Selection and Facility Layout In Out Workers Figure 6.6 A U-Shaped Production Line

6-22Process Selection and Facility Layout Dept. A Dept. BDept. D Dept. C Dept. F Dept. E Used for Intermittent processing Job Shop or Batch Process Layout (functional) Figure 6.7 Process Layout

6-23Process Selection and Facility Layout Work Station 1 Work Station 2 Work Station 3 Figure 6.7 (cont’d) Product Layout (sequential) Used for Repetitive Processing Repetitive or Continuous Product Layout

6-24Process Selection and Facility Layout  Can handle a variety of processing requirements  Not particularly vulnerable to equipment failures  Equipment used is less costly  Possible to use individual incentive plans Advantages of Process Layouts

6-25Process Selection and Facility Layout  In-process inventory costs can be high  Challenging routing and scheduling  Equipment utilization rates are low  Material handling slow and inefficient  Complexities often reduce span of supervision  Special attention for each product or customer  Accounting and purchasing are more involved Disadvantages of Process Layouts

6-26Process Selection and Facility Layout  Cellular Production  Layout in which machines are grouped into a cell that can process items that have similar processing requirements  Group Technology  The grouping into part families of items with similar design or manufacturing characteristics Cellular Layouts

6-27Process Selection and Facility Layout DimensionFunctionalCellular Number of moves between departments manyfew Travel distanceslongershorter Travel pathsvariablefixed Job waiting timesgreatershorter Throughput timehigherlower Amount of work in process higherlower Supervision difficultyhigherlower Scheduling complexityhigherlower Equipment utilizationlowerhigher Table 6.3 Functional vs. Cellular Layouts

6-28Process Selection and Facility Layout  Warehouse and storage layouts  Retail layouts  Office layouts Other Service Layouts

6-29Process Selection and Facility Layout Line Balancing is the process of assigning tasks to workstations in such a way that the workstations have approximately equal time requirements. Design Product Layouts: Line Balancing

6-30Process Selection and Facility Layout Cycle time is the maximum time allowed at each workstation to complete its set of tasks on a unit. Cycle Time

6-31Process Selection and Facility Layout Determine Maximum Output

6-32Process Selection and Facility Layout Determine the Minimum Number of Workstations Required

6-33Process Selection and Facility Layout Precedence diagram: Tool used in line balancing to display elemental tasks and sequence requirements A Simple Precedence Diagram a b cd e 0.1 min. 0.7 min. 1.0 min. 0.5 min.0.2 min. Figure 6.10 Precedence Diagram

6-34Process Selection and Facility Layout  Arrange tasks shown in Figure 6.10 into three workstations.  Use a cycle time of 1.0 minute  Assign tasks in order of the most number of followers Example 1: Assembly Line Balancing

6-35Process Selection and Facility Layout Workstation Time RemainingEligible Assign Task Revised Time Remaining Station Idle Time a, c c none ac-ac bb de-de- de-de Example 1 Solution

6-36Process Selection and Facility Layout Efficiency = 1 – Percent idle time Calculate Percent Idle Time

6-37Process Selection and Facility Layout  Assign tasks in order of most following tasks.  Count the number of tasks that follow  Assign tasks in order of greatest positional weight.  Positional weight is the sum of each task’s time and the times of all following tasks. Some Heuristic (intuitive) Rules: Line Balancing Rules

6-38Process Selection and Facility Layout cd abe fgh Example 2

6-39Process Selection and Facility Layout Station 1Station 2Station 3Station 4 ab e f d g h c Solution to Example 2

6-40Process Selection and Facility Layout 1 min.2 min.1 min. 30/hr. 1 min. 60/hr. 30/hr. 60/hr. 1 min. 30/hr. Bottleneck Parallel Workstations

6-41Process Selection and Facility Layout Information Requirements: 1. List of departments 2. Projection of work flows 3. Distance between locations 4. Amount of money to be invested 5. List of special considerations 6. Location of key utilities Designing Process Layouts