The product or line layout is the basic type of layout commonly used by the food industry. Line balancing is done to analyze the net output of our production line and processing time at various steps.
2. Layout Planning
โข Layout planning is planning that involves decisions about the physical
arrangement of economic activity centers needed by a facilityโs various processes.
โข Layout plans translate the broader decisions about the competitive priorities, process strategy,
quality, and capacity of its processes into actual physical arrangements.
โข 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.
2
3. Objectives of facility layout
Main: smooth flow of work, material and information
Supporting objectives:
3
4. Types of Layouts
โข Four basic layout types consisting of:
โข Process layouts - Group similar resources together
โข Product layouts - Designed to produce a specific product efficiently
โข Hybrid layouts - Combine aspects of both process and product
layouts
โข Fixed-Position layouts - Product is two large to move; e.g. a
building
4
5. Selection
Search
Analysis
Systematic Layout Planning
Muther (1961)
0 Data gathering
10 Evaluation
4 Space
requirements
5 Space
available
6 Space relationship
diagram
1 Flow 2 Activities
3 Relationship
diagram
7 Reasons to
modify
8 Restrictions
9 Layout alternatives
5
6. Used for Repetitive or Continuous Processing
Product Layout
N. Ramesh(2014)
6
7. Advantages of Product Layout
โข High rate of output
โข Low unit cost
โข Labor specialization
โข Low material handling cost
โข High utilization of labor and equipment
โข Established routing and scheduling
โข Routing accounting and purchasing
7
8. Disadvantages of Product Layout
โข Creates dull, repetitive jobs
โข Poorly skilled workers may not maintain equipment or
quality of output
โข Fairly inflexible to changes in volume
โข Highly susceptible to shutdowns
โข Needs preventive maintenance
8
9. Designing Line-Flow Layouts
โข 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.
โข Work elements are the smallest units of work that can be performed
independently.
โข Immediate predecessors are work elements that must be done before the next
element can begin.
โข 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.
9
10. Cycle Time
Cycle time is the maximum time allowed at each
workstation to complete its set of tasks on a unit.
tmax < Cycle time < โt
Wiley 4th edition, 2004
10
11. Determine the Minimum Number of Workstations Required
Theoretical Nmin is not necessarily will be the Nactual. The latter is affected by
other technical and practical considerations, too. Nmin โค Nactual
(rounded up to the next integer)
11
12. A diagram that shows elemental tasks and their
precedence requirements.
A simplified precedence
diagrama b
c d e
0.1 min.
0.7 min.
1.0 min.
0.5 min. 0.2 min.
Precedence Diagram
12
13. Efficiency %= 100 x (1 โ Percentage of idle time)
Calculate Percent Idle Time and efficiency
Wiley 4th edition, 2004
13
14. Designing Product Layouts โ conโt
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
14
15. 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
15
16. Layout Calculations
โข Step 2: Determine output rate
โข Vicki needs to produce 60 pizzas per hour
โข Step 3: Determine cycle time
โข The amount of time each workstation is allowed to complete its tasks
โข Limited by the bottleneck task (the longest task in a process):
๏จ ๏ฉ
๏จ ๏ฉ
sec./unit60
units/hr60
sec/min60min/hr x60
units/hroutputdesired
sec./daytimeavailable
)(sec./unittimeCycle ๏ฝ๏ฝ๏ฝ
hourperpizzasorunits/hr,72
sec./unit50
sec./hr.3600
timeneck taskbottle
timeavailable
outputMaximum ๏ฝ๏ฝ๏ฝ
16
17. Layout Calculations conโt
โข Step 4: Compute the theoretical minimum number of stations
โข TM = number of stations needed to achieve 100% efficiency (every second is
used)
โข Always round up (no partial workstations)
โข Serves as a lower bound for our analysis
๏จ ๏ฉ
stations3or2.75,
nsec/statio60
seconds165
timecycle
timestask
TM ๏ฝ๏ฝ๏ฝ
๏ฅ
17
18. Layout Calculations conโt
โข Step 5: Assign tasks to workstations
โข Start at the first station & choose the longest eligible task following precedence relationships
โข Continue adding the longest eligible task that fits without going over the desired cycle time
โข When no additional tasks can be added within the desired cycle time, begin assigning tasks to
the next workstation until finished
18
19. Last Layout Calculation
โข Step 6: Compute efficiency and balance delay
โข Efficiency (%) is the ratio of total productive time divided by total time
โข Balance delay (%) is the amount by which the line falls short of 100%
๏จ ๏ฉ 91.7%100
sec.60xstations3
sec.165
NC
t
(%)Efficiency ๏ฝ๏ฝ๏ฝ
๏ฅ
8.3%91.7%100%delayBalance ๏ฝ๏ญ๏ฝ
19
20. Other Product Layout Considerations
โข Shape of the line (S, U, O, L):
โข Share resources, enhance communication & visibility, impact location of loading
& unloading
โข Paced versus Un-paced lines
โข Paced lines use an automatically enforced cycle time
โข Number of Product Models produced
โข Single
โข Mixed-model lines
20