Chapter 10 - Facility Layout Location Discussion 3:The study of facility location problems, also known as location analysis, is a branch of operations research and computational geometry concerned with the optimal placement of facilities

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Chapter 10 - Facility Layout

Operations Management

6th Edition

Instructor: Dr. Henrietta Okoro

Learning Objectives

 Define layout planning and explain its importance.

 Identify and describe different types of layouts.

 Describe the steps involved in designing a process

layout.

 Describe the two special cases of process layout.

 Describe the steps involved in designing a product

layout.

 Explain the meaning of group technology (cell) layouts.

What Is Layout Planning?

Deciding the best physical arrangement of all resources that

consume space within a facility

 Facility resource arrangement can significantly affect

productivity

 Two broad categories of operations:

 Intermittent processing systems – low volume of many different

products

 Repetitive processing systems – high volume of a few standardized

products

Types of Layouts

 Four basic layout types:

 Process layouts - Group similar resources together

based on similar processes/functions

 Product layouts - Designed to produce a specific

product efficiently

 Hybrid layouts - Combine aspects of both process and

product layouts

 Fixed-Position layouts - Product is two large to move;

e.g. a building

Process Layouts

 Unique characteristics include:  Resources used are general purpose

 Facilities are less capital intensive

 Facilities are more labor intensive

 Resources have greater flexibility

 Processing rates are slower

 Material handling costs are higher

 Scheduling resources & work flow is more complex

 Space requirements are higher

Examples: Hospital University Metalworking shop Department store Tool & Die Manuf. Wal-Mart

Product Layouts

 Unique characteristics are:

 Resources are specialized

 Facilities are capital intensive

 Processing rates are faster

 Material handling costs are lower

 Space requirements for inventory storage are lower

 Flexibility is low relative to the market

Examples: Assembly lines See’s Candies Cafeterias Car Wash Toyota

Process vs. Product Layouts 7

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

 Group technology or cell layouts

 Identification of parts of the process layout operation that

can be standardized and produce them in a product layout

format

Examples: Winnebago Retail stores Grocery stores

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

Examples: Construction Dam Bridge Shipbuilding Aircraft Manuf.

Designing Process Layouts

Step 1: Gather information:

Space needed, space available, identify closeness measures (From-to Matrix, REL, SLP)

Step 2: Develop alternative block plans:

Using trial-and-error or decision support tools (load-distance model, ALDEP, CRAFT)

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

Special Cases of Process Layouts - Warehouse Layouts

 Warehouse Layout Considerations:  Primary decision is where to locate each department relative

to the dock

 Storage areas of equal sizes  Assign departments to locations in order to minimize the

number of trips to the dock.

 Storage areas of unequal sizes  STEP 1: Take the ratio of the number of trips relative to the

storage area required.

 STEP 2: Use the ratios from Step 1 to make assignments. Assign the department with the highest ratio closest to the dock. Next, assign the department with the second-highest ratio second closest to the dock. Continue in this manner until all departments have been assigned.

Special Cases of Process Layouts - Office Layouts

 Office Layout Considerations:  Almost half of US workforce works in an office environment

 Human interaction and communication are the primary factors in designing office layouts

 Layouts need to account for physical environment and psychological needs of the organization

 Key trade-off is between proximity and privacy

 Open concept offices promote understanding & trust

 Flexible layouts incorporating “office landscaping” help to solve the privacy issue in open office environments

Designing Product Layouts

 Designing product layouts requires consideration of:

 Sequence of tasks to be performed by each workstation

 Logical order

 Speed considerations – line balancing

Designing Product Layouts – cont'd

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

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

Step 2: Determine Output Rate

 Output Rate is the number of units to be produced over a

specific period of time

 Vicki needs to produce 600 pizzas per hour

 Vicki will need to divide the work among a number of

people simultaneously at workstations

 The goal is to design a product layout that can produce the

desired number of units with the least amount of work

centers and a balance of workload

hourper pizzas 8.12 sec./unit 165

sec./hr. 3600 output M aximum ==

Step 3: Determine Cycle Time

 Determine cycle time calculations

 The amount of time each workstation is allowed to complete its

tasks

 Limited by the bottleneck task (the longest task):

 Minimum cycle time = bottleneck

 Maximum cycle time = sum of the task times

( ) ( )

sec./unit 60 units/hr 60

sec/min 60x min/hr 60

units/hroutput desired

sec./day time available )(sec./unit time Cycle ===

hourper pizzas 8.12 sec./unit 165

sec./hr. 3600 output Maximum ==

Step 4: Theoretical Minimum Number of Stations

 Computing the theoretical minimum (TM) 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 3or 2.75,

nsec/statio 60

seconds 165

time cycle

times task TM ===



Step 5: Assign Tasks to Workstations

 Assigning tasks to workstations (Balance the Line)

 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

Step 6: Efficiency and Balance Delay

 Computing 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. 60x stations 3

sec. 165

t (%) Efficiency === 

8.3%91.7%100%delay Balance =−=

Other Product Layout Considerations

 Shape of the line (S, U, O, L):  Share resources, enhance communication & visibility, impact

location of loading & unloading

 Paced versus Un-paced lines  Paced lines use an automatically enforced cycle time

 Un-paced has more autonomy; product may be removed off assembly line

 Number of Product Models produced  Single-model lines – one version of a product

 Mixed-model lines – many versions of a product

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

Process Flows Before and After The Use of GT Cells

Facility Layout Within OM: How It All Fits Together

 Layout decisions are directly related to issues of product design and process selection (Ch 3).

 Job design, as process layouts tend to require greater worker skills than do product layouts (Ch 11).

 Degree of automation, as product layouts tend to be more capital intensive and use more automation compared to process layouts (Ch 3).

 Layout decisions are also affected by implementation of just-in- time (JIT) systems, which dictate a line flow and the use of group technology (GT) cells (Ch 7).

 As layout decisions specify the flow of goods through the facility, they impact all other aspects of operations management.

Facility Layout Across The Organization

 Layout planning is organizationally important for an

efficient operations

 Marketing is affected by layout especially when clients come to

the site

 Human Resources is affected as layout impacts people

 Finance is involved as layout changes can be costly endeavors

Chapter 10 Highlights

 Layout planning is deciding on the best physical arrangement of all resources that consumes space within a facility. Proper layout planning is highly important for the efficient running of a business. Otherwise, there can be much wasted time and energy, as well as confusion.

 There are four basic types of layouts: process, product, hybrid, and fixed position. Process layouts group resources based on similar processes. Product layouts arrange resources in straight- line fashion. Hybrid layouts combine elements of both process and product layouts. Fixed-position layouts occur when the product is larger and cannot be moved.

Chapter 10 Highlights – cont'd

 Process layouts provide much flexibility and allow for the production of many products with differing characteristics.

 Product layouts, on the other hand, provide greater efficiency when producing one type of product.

 The 3 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.

Chapter 10 Highlights – cont'd

 The 6 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 have advantages over other layout types

because they combine elements of both process and product

layouts to increase efficiency.

Chapter 10 Highlights – cont'd

 An example of hybrid layouts is group technology or cell

layouts. Group technology is the process of crating groupings

of 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.