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McGraw-Hill/Irwin Copyright © 2007 by The McGraw-Hill Companies, Inc. All rights reserved. 6 Process Selection and Facility Layout.

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Presentation on theme: "McGraw-Hill/Irwin Copyright © 2007 by The McGraw-Hill Companies, Inc. All rights reserved. 6 Process Selection and Facility Layout."— Presentation transcript:

1 McGraw-Hill/Irwin Copyright © 2007 by The McGraw-Hill Companies, Inc. All rights reserved. 6 Process Selection and Facility Layout

2 6-2 Learning Objectives  Explain the strategic importance of process selection.  Describe the basic processing types.  List some reasons for redesign of layouts.  Describe the basic layout types.  List the main advantages and disadvantages of product layouts and process layouts.  Solve simple line-balancing problems.  Develop simple process layouts.

3 6-3  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

4 6-4  Variety  How much  Flexibility  What degree  Volume  Expected output Job Shop Batch Repetitive Continuous Process Selection

5 6-5  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 6-6 Process Type Job Shop Appliance repair Emergency room Ineffective Batch Commercial baking Classroom Lecture Repetitive Automotive assembly Automatic carwash Continuous (flow) IneffectiveSteel Production Water purification Figure 6.2 Product and Service Processes low volume high low variety high

7 6-7  Layout: the configuration of departments, work centers, and equipment, with particular emphasis on movement of work (customers or materials) through the system  Product layouts  Process layouts  Fixed-Position layout  Combination layouts Facilities Layout

8 6-8 Objective of Layout Design 1.Facilitate attainment of product or service quality 2.Use workers and space efficiently 3.Avoid bottlenecks 4.Minimize unnecessary material handling costs 5.Eliminate unnecessary movement of workers or materials 6.Minimize production time or customer service time 7.Design for safety

9 6-9  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

10 6-10  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

11 6-11 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

12 6-12  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

13 6-13  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

14 In Out Workers Figure 6.6 A U-Shaped Production Line

15 6-15 Process Layout - work travels to dedicated process centers Milling Assembly & Test Grinding Drilling Plating Process Layout

16 6-16 Gear cutting Mill Drill Lathes Grind Heat treat Assembly Process Layout

17 6-17  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

18 6-18  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

19 6-19 Fixed Position Layouts  Fixed Position Layout: Layout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed.  Nature of the product dictates this type of layout  Weight  Size  Bulk  Large construction projects  Ship/Boat production

20 6-20  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

21 Assembly Lathe Mill Drill Heat treat Heat treat Heat treat Gear cut Gear cut Grind Cellular Manufacturing Layout

22 6-22  Warehouse and storage layouts  Retail layouts  Office layouts  Service layouts must be aesthetically pleasing as well as functional Service Layouts

23 6-23 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

24 6-24 Cycle time is the maximum time allowed at each workstation to complete its set of tasks on a unit. Cycle Time

25 6-25 Determine Maximum Output

26 6-26 Determine the Minimum Number of Workstations Required

27 6-27 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 6.11 Precedence Diagram

28 6-28  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

29 6-29 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

30 6-30 Efficiency = 1 – Percent idle time Calculate Percent Idle Time

31 6-31  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

32 6-32 Example 2 Try problem 2, pg 269


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