layout10
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Chapter 10 – Facility Layout
Operations Management
Learning Objectives Define layout planning and its importance Identify and describe different types of
layouts Compare process layouts & product layouts Describe the steps involved in designing
both process and product layouts Explain the advantages of hybrid layouts Define the meaning of group technology &
its importance to cellular layouts
What Is Layout Planning
Layout planning is determining the best physical arrangement of resources within a facility
Two broad categories of operations: Intermittent processing systems Continuous processing systems
Types of Layouts Process layouts:
Group similar resources together 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 General purpose & flexible resources Lower capital intensity & automation Higher labor intensity Resources have greater flexibility Processing rates are slower Material handling costs are higher Scheduling resources & work flow is
more complex Space requirements are higher
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
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
Examples: Group technology & manufacturing cells Grocery stores
Comparison of Product vs. Product Layouts
Process Layouts Product LayoutsProducts: large #, different small # efficiently
Resources: general purpose specialized
Facilities: more labor intensive more capital intensive
Flexibility: greater relative to market lower relative to market
Processing slower fasterRates:
Handling costs: high low
Space requirements: higher lower
Designing Process Layouts Step 1: Gather information:
Space needed, space available, importance of proximity between various units
Step 2: Develop alternative block plans: Using trial-and-error or decision support tools
Step 3: Develop a detailed layout Consider exact sizes and 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
Process Layout Steps Step 1: Gather information like space needed, from-to
matrix, and REL Chart for Recovery First Sports Medicine Clinic (total space 3750 sq. ft.)
ARadiology
400 sq. ft.
BLaboratory
300 sq. ft.
CLobby & Waiting
300 sq. ft.
DExamining
Rooms800 sq. ft.
ESurgery & Recovery900 sq. ft.
FPhysical Therapy
1050 sq. ft.
Step 1: Gather Information
(continued)
Step 2: Develop a New Block Layout Use trial and error with from-to and REL Charts as a guide Use computer software like ALDEP or CRAFT
Warehouse Layouts
Warehouse Layout Considerations: Primary decision is where to locate each
department relative to the dock Departments can be organized to minimize “ld”
totals Departments of unequal size require modification
of the typical ld calculations to include a calculation of the “ratio of trips to area needed”
The usage of “Crossdocking” (see Ch.4) modifies the traditional warehouse layouts; more docks, less storage space, and less order picking
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
One key layout 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 Step 1: Identify tasks & immediate predecessors Step 2: Determine the desired output rate Step 3: Calculate the cycle time Step 4: Compute the theoretical minimum number of workstations Step 5: Assign tasks to workstations (balance the line) Step 6: Compute efficiency, idle time & balance delay
Step 1: Identify Tasks & Immediate PredecessorsExample 10.4 Vicki's Pizzeria and the Precedence Diagram
Immediate Task TimeWork Element Task Description Predecessor (seconds
A Roll dough None 50B Place on cardboard backing A 5C Sprinkle cheese B 25D Spread Sauce C 15E Add pepperoni D 12F Add sausage D 10G Add mushrooms D 15H Shrinkwrap pizza E,F,G 18I Pack in box H 15
Total task time 165
Layout Calculations
Step 2: Determine output rate Vicki needs to produce 60 pizzas per hour
Step 3: Determine cycle time The amount of time each workstation is
allowed to complete its tasks
Limited by the bottleneck task (the longest task in a process):
sec./unit 60
units/hr 60
sec/min 60x min/hr 60
units/hroutput desired
sec./day time available)(sec./unit time Cycle
hourper pizzasor units/hr, 72sec./unit 50
sec./hr. 3600
time task bottleneck
time availableoutput Maximum
Layout Calculations (continued)
Step 4: Compute the theoretical minimum 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 taskTM
Layout Calculations (continued)
Step 5: Assign tasks to workstations 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 finishedWorkstation Eligible task Task Selected Task time Idle time
A A 50 10
B B 5 5
C C 25 35
D D 15 20
E, F, G G 15 5
E, F E 12 48
F F 10 38
H H 18 20
I I 15 5
1
2
3
Last Layout Calculation Step 6: Compute 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%100sec. 60x stations 3
sec. 165
NC
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 Single or mixed-model lines
Designing Hybrid 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 the Use of GT Cells
Process Flows after the Use of GT Cells
Chapter 10 Highlights Layout planning is deciding on the best
physical arrangement of resources. There are four basic types of layouts: process,
product, hybrid, and fixed position. Process layouts provide flexibility to make a
variety of different products. Product layouts provide greater efficiency for one product.
The steps for designing process layouts are: gather space and closeness information, develop a block plan, and develop a detailed layout.
Chapter 10 Highlights (continued)
The steps for designing an product layout are: identify tasks and predecessors, determine output rate, determine cycle time, computing the theoretical minimum number of work stations, assigning tasks to workstations, and computing efficiency and balance delay.
Hybrids layouts combine elements from both types of layouts to increase efficiency.
Hybrid layouts combine GT analysis with cellular layout concepts .
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