OMG 402 - Operations Management
Spring 1997
CLASS 4:
THE PUFF LINE INSTRUCTIONS
Raw
Puffs
LOAD
Pallets
MOVE
SHIP
The Puff Line
• LOAD station: puffs placed on a pallet
• MOVE station: when filled, pallets moved from
LOAD to SHIP
• SHIP station: puffs taken off pallet and shipped to
customer
production rounds at all stations are synchronized
2
The Puff Line: Deterministic
Capacity
A deterministic system with constant capacity
• Three puffs loaded onto pallet per round.
• After being filled, pallet moved in the following
round.
• After being moved, three puffs are shipped in the
following round.
What is the capacity of this system (in puffs/round)?
3
Data Collection
• Number in system at beginning of each
round (puffs);
• Output of system during each round
(puffs/round);
• Time in system for ‘tagged’ items (rounds).
4
Deterministic Capacity Results
• Average number in system =
• Average output from the system =
• Average time in system =
5
The Puff Line: Random Capacity
LOAD and SHIP have variable, random capacities.
• Number of puffs loaded = zero or six from coin flip
heads = six puffs loaded
tails = zero puffs loaded
• Full pallets moved in round after being filled.
• Number of puffs shipped = zero or six from coin flip
heads = six puffs shipped
tails = zero puffs shipped
6
The Puff Line: Random Capacity
• Average capacity of loading:
• Average capacity of shipping:
• Predict average throughput:
• Predict average WIP:
7
Random Capacity Results
• Average number in system =
• Average output from the system =
• Average time in system =
8
Insights from The Puff Line
• Impact of batching:
• Impact of variability:
9
20
10
Round
41
31
21
11
0
41
31
21
100
80
60
40
20
0
Round
41
30
Round
31
40
Number of Puffs in Buffer
50
0
41
31
21
Round
1
Number of Puffs in Buffer
11
0
10
21
10
20
11
20
30
11
30
40
1
40
50
1
50
1
Number of Puffs in Buffer
Four Examples from a Simulation:
Number of Puffs in Buffer
Puff Line with Random Capacity:
WIP in MOVE output buffer
10
PALLETS
RAW PUFFS
SHIPPED PUFFS
LOAD STATION
MOVE STATION
SHIP STATION
LOAD STATION
OUTPUT BUFFER
MOVE STATION
OUTPUT BUFFER