D D
D D
G G
G G
G G
M M
M M
M M
A A
A A
L
L L
L L
L L
L
Process Layout
How Process Layout fits the Operations Management
Philosophy
Operations As a Competitive Weapon
Operations StrategyProject Management Process Strategy
Process AnalysisProcess Performance and Quality
Constraint ManagementProcess Layout
Lean Systems
Supply Chain StrategyLocation
Inventory ManagementForecasting
Sales and Operations PlanningResource Planning
Scheduling
Outline
1. What is layout planning
2. Strategic issues
3. Creating hybrid layouts
4. Design flexible-flow layouts
5. Designing line-flow layouts
Layout Planning
Layout planning is planning that involves decisions about the physical arrangement of economic activity centers needed by a facility’s various processes. Layout plans translate the broader decisions about the
competitive priorities, process strategy, quality, and capacity of its processes into actual physical arrangements.
Economic activity center: Anything that consumes space -- a person or a group of people, a customer reception area, a teller window, a machine, a workstation, a department, an aisle, or a storage room.
Before a manager can make decisions regarding physical arrangement, four questions must be addressed.
1. What centers should the layout include?
2. How much space and capacity does each center need?
3. How should each center’s space be configured?
4. Where should each center be located?
Layout Planning Questions
Location Dimensions
The location of a center has two dimensions:
1. Relative location: The placement of a center relative to other centers.
2. Absolute location: The particular space that the center occupies within the facility.
Absolute Locations vs. Relative Locations
Original layout
Frozen foods
Dry groceries
Bread Vegetables
Meats
Frozen foods
Dry groceries
BreadVegetables
Meats
Revised layout
Four of the absolute locations have changed but not the relative locations.
Strategic Issues
Layout choices can help communicate an organization’s product plans and competitive priorities.
Altering a layout can affect an organization and how well it meets its competitive priorities in the following ways:
1. Increasing customer satisfaction and sales at a retail store.2. Facilitating the flow of materials and information.3. Increasing the efficient utilization of labor and equipment.4. Reducing hazards to workers.5. Improving employee morale.6. Improving communication.
Performance Criteria
Customer satisfaction Level of capital investment Requirements for materials handling Ease of stockpicking Work environment and “atmosphere” Ease of equipment maintenance Employee and internal customer attitudes Amount of flexibility needed Customer convenience and levels of sales
Types of Layouts
Flexible-flow layout: A layout that organizes resources (employees) and equipment by function rather than by service or product.
Line-flow layout: A layout in which workstations or departments are arranged in a linear path.
Hybrid layout: An arrangement in which some portions of the facility have a flexible-flow and others have a line-flow layout.
Fixed-position layout: An arrangement in which service or manufacturing site is fixed in place; employees along with their equipment, come to the site to do their work.
A Flexible Flow Layout
FoundryMilling
machines
LathesGrinding
Painting Drills
Office
Welding
Forging
A job shop has a flexible-flow layout.
Line Flow Layout
Station 1 Station 2 Station 3 Station 4
A production line has a line-flow layout.
Creating Hybrid Layouts
Layout flexibility is the property of a facility to remain desirable after significant changes occur or to be easily and inexpensively adopted in response to changes.
A One-worker, multiple-machines (OWMM) cell is a one-person cell in which a worker operates several different machines simultaneously to achieve a line flow.
A Cell is two or more dissimilar workstations located close together through which a limited number of parts or models are processed with line flows.
Machine 1
Machine 2
Machine 3
Machine 4Machine
5
Materials in
Finished goods out
One Worker, One Worker, Multiple Machines Multiple Machines
Group Technology (GT)
Group Technology (GT) is an option for achieving line-flow layouts with low-volume processes; this technique creates cells not limited to just one worker and has a unique way of selecting work to be done by the cell.
The GT method groups parts or products with similar characteristics into families and sets aside groups of machines for their production.
Group Technology
Parts FamiliesParts Families
Before Group Technology
Drilling
D D
D D
Grinding
G G
G G
G G
Milling
M M
M M
M M
Assembly
A A
A A
Lathing
Receiving and shipping
L
L L
L L
L L
L
Jumbled flows in a job shop without GT cellsJumbled flows in a job shop without GT cells
Applied Group TechnologyLine flows in a job shop with three GT cells Line flows in a job shop with three GT cells
Cell 3
L M G G
Cell 1 Cell 2
Assembly area
A A
L M DL
L MShipping
D
Receiving
G
Designing Flexible-Flow Layouts
Step 1: Gather information Space requirements by center Available space Closeness factors: which centers need to be located close
to one another.
Closeness matrix: A table that gives a measure of the relative importance of each pair of centers being located close together.
Step 2: Develop a Block plan: A plan that allocates space and indicates placement of each department.
Step 3: Design a detailed layout.
Gather Information
100'
150'
3 6 4
1 2 5
Current Block Plan
Department Area Needed (ft2)
1. Administration 3,5002. Social services 2,6003. Institutions 2,4004. Accounting 1,6005. Education 1,5006. Internal audit 3,400
Total 15,000
Space Requirements
Example 8.1 Office of Budget Management
100'
150'
3 6 4
1 2 5 Closeness Matrix
Trips between Departments
Department 1 2 3 4 5 6
1. Administration —
2. Social services —
3. Institutions —
4. Accounting —
5. Education —
6. Internal audit —
3 6 5 6 10
8 1 1
3 9
2
1
Departments 1 and 6 have the most interaction.Departments 3 and 5 have the next highest.
Departments 2 and 3 have next priority.
Example 8.1 Office of Budget Management
100'
150'
100'
150'
3 6 4
1 2 5 Proposed Block Plan
First put departments 1 and 6 close together
1
6
Next put departments 3 and 5 close together
5
3
Then put departments 2 and 3 close together
2
4
Weighted-distance method: A mathematical model used to evaluate flexible-flow layouts based on proximity factors.
Euclidean distance is the straight-line distance, or shortest possible path, between two points.
Rectilinear distance: The distance between two points with a series of 90 degree turns, as along city blocks.
Applying the Weighted- Distance Method
Distance Measures
Rectilinear DistanceRectilinear Distance
ddABAB = |= |xxAA –– x xBB| + || + |yyAA – – yyBB||
Euclidian DistanceEuclidian Distance
ddABAB = (= (xxAA –– x xBB))22 + ( + (yyAA – – yyBB))22
Application 8.1
Rectilinear DistanceRectilinear Distance
ddABAB = |20= |20 –– 80| + |10 – 60| = 11080| + |10 – 60| = 110
Euclidian DistanceEuclidian Distance
ddABAB = (20= (20 –– 80)80)22 + (10 – 60) + (10 – 60)22
= 78.1= 78.1
What is the distance between (20,10) and (80,60)?
© 2007 Pearson Education
Example 8.2 Load Distance Analysis
Current Plan Proposed Plan
Dept Closeness Distance DistancePair Factor, w d wd Score d wd Score
1,2 3 1 3 2 61,3 6 1 6 3 181,4 5 3 15 1 51,5 6 2 12 2 121,6 10 2 20 1 102,3 8 2 16 1 82,4 1 2 2 1 12,5 1 1 1 2 23,4 3 2 6 2 63,5 9 3 27 1 94,5 2 1 2 1 25,6 1 2 2 3 3
ld =112 ld = 82
Calculating the WD Score
Other Decision Support Tools
Automated layout design program (ALDEP): A computer software package that constructs a good layout from scratch, adding one department at a time.
Computerized relative allocation of facilities technique (CRAFT): A heuristic method that begins with the closeness matrix and an initial block layout, and makes a series of paired exchanges of departments to find a better block plan.
Warehouse LayoutsOut-and-back Pattern
The most basic warehouse layout is the out-and-back pattern. The numbers indicate storage areas for same or similar items.
Dock Aisle
Storage area
Storage area
3 5 5 6 4 2 7
1 5 5 4 4 2 7
Warehouse LayoutsZone System
Click to add titleZones Zones Control
station Shipping doors
Tractor trailer
Tractor trailer
Overflow
Feeder lines
Feeder lines
Office Layouts
Most formal procedures for designing office layouts try to maximize the proximity of workers whose jobs require frequent interaction.
Privacy is another key factor in office design.
Four common office layouts:
1. Traditional layouts
2. Office landscaping (cubicles/movable partitions)
3. Activity settings
4. Electronic cottages (Telecommuting)
Designing Line-Flow Layouts
Line balancing is the assignment of work to stations in a line so as to achieve the desired output rate with the smallest number of workstations.
Work elements are the smallest units of work that can be performed independently.
Immediate predecessors are work elements that must be done before the next element can begin.
Precedence diagram allows one to visualize immediate predecessors better; work elements are denoted by circles, with the time required to perform the work shown below each circle.
Line Balancing Example 8.3Example 8.3
Green Grass, Inc., a manufacturer of lawn & garden equipment, is designing an assembly line to produce a new fertilizer spreader, the Big Broadcaster. Using the following information, construct a precedence diagram for the Big Broadcaster.
© 2007 Pearson Education
Line Balancing Green Grass, Inc.Green Grass, Inc.
66
E2020
H
1818
I
4040
D
3030
B
2525
F
5050
C4040
A
1515
G
AA Bolt leg frame to hopperBolt leg frame to hopper 4040 NoneNoneBB Insert impeller shaftInsert impeller shaft 30 30 AACC Attach axleAttach axle 5050 AADD Attach agitatorAttach agitator 4040 BBEE Attach drive wheelAttach drive wheel 66 BBFF Attach free wheelAttach free wheel 2525 CCGG Mount lower postMount lower post 1515 CCHH Attach controlsAttach controls 2020 D, ED, EII Mount nameplateMount nameplate 1818 F, GF, G
TotalTotal 244244
WorkWork Time Time Immediate ImmediateElementElement DescriptionDescription (sec) (sec) Predecessor(s) Predecessor(s)
Desired Output Rate and Cycle Time
Desired output rate, r must be matched to the staffing or production plan.
Cycle time, c is the maximum time allowed for work on a unit at each station: 1
rc =
Theoretical Minimum
Theoretical minimum (TM ) is a benchmark or goal for the smallest number of stations possible, where total time required to assemble each unit (the sum of all work-element standard times) is divided by the cycle time. It must be rounded up
Idle time is the total unproductive time for all stations in the assembly of each unit.
Efficiency (%) is the ratio of productive time to total time.
Balance Delay is the amount by which efficiency falls short of 100%.
Output Rate and Cycle TimeExample 8.4
Green Grass, Inc. Desired output rate, r = 2400/week Plant operates 40 hours/week r = 2400/40 = 60 units/hour
Cycle time, c = 1/60
= 1 minute/unit
= 60 seconds/unit
1
r
Calculations for Example 8.4 continued
Theoretical minimum (TM ) - sum of all work-element standard times divided by the cycle time.
TM = 244 seconds/60 seconds = 4.067 It must be rounded up to 5 stations
Cycle time: c = 1/60 = 1 minute/unit = 60 seconds/unit
Efficiency (%) - ratio of productive time to total time.
Efficiency = [244/5(60)]100 = 81.3%
Balance Delay - amount by which efficiency falls short of 100%.
(100 − 81.3) = 18.7%
© 2007 Pearson Education
S1
S2S3
S5S4 66
E2020
H
1818
I
4040
D
3030
B
2525
F
5050
C4040
A
1515
G
Green Grass, Inc. Green Grass, Inc. Line Balancing SolutionLine Balancing Solution
cc = 60 seconds/unit = 60 seconds/unitTM = 5 stationsTM = 5 stationsEfficiency = 81.3%Efficiency = 81.3%
The goal is to cluster the work elements into 5 workstations so that the number of work-stations is minimized, and the cycle time of 60 seconds is not violated. Here we use the trial-and-error method to find a solution, although commercial software packages are also available.
Other Considerations
In addition to balancing a line, managers must also consider four other options:
1. Pacing: The movement of product from one station to the next as soon as the cycle time has elapsed.
2. Behavioral factors of workers.3. Number of models produced: A mixed-model line
produces several items belonging to the same family.
4. Cycle times depend on the desired output rate, and efficiency varies considerably with the cycle time selected. Thus exploring a range of cycle times makes sense.
Top Related