1. Bottleneck Analysis and Theory of Constraints
Each work area has its own unique capacity based on the station process time required
Capacity analysis determines the throughput capacity of workstations in a system
A bottleneck is a limiting factor or constraint
A bottleneck has the lowest effective capacity in a system

2. Process Times for Stations, Systems, and Cycles
The process time of a station is the time it takes to produce a unit at that workstation
The bottleneck time is the time of the longest process time in the system
The throughput time is the time it takes for a product to go through production from start to end (assuming no waiting)

3. A Four-Station Assembly Line
20 min/unit
8 min/unit
15 min/unit A B C
10 min/unit D

4. Capacity Analysis Two identical sandwich lines
Each line has two workers and a toaster to perform the three operations
All completed sandwiches are wrapped
Wrap
37.5 sec/sandwich
Order
30 sec/sandwich
Bread
Fill
Toast
15 sec/sandwich
20 sec/sandwich
40 sec/sandwich
© 2011 Pearson Education, Inc. publishing as Prentice Hall

5. Capacity Analysis With Parallel Stations
The bottleneck is the operation with the longest process time after dividing by the number of parallel operations
The system capacity is the inverse of the bottleneck time
The throughput time is the total time through the longest path in the system, assuming no waiting

6. Capacity Analysis
Wrap
37.5 sec
Order
30 sec
Bread
Fill
Toast
15 sec
20 sec
40 sec
Toast work station has the longest processing time – 40 seconds
The two lines each deliver a sandwich every 40 seconds so the process time of the combined lines is 40/2 = 20 seconds
At 37.5 seconds, wrapping and delivery has the longest processing time and is the bottleneck
Capacity per hour is 3,600 seconds/37.5 seconds/sandwich = 96 sandwiches per hour
Throughput time is = seconds
© 2011 Pearson Education, Inc. publishing as Prentice Hall

7. Bottleneck Management
Release work orders to the system at the pace set by the bottleneck
Lost time at the bottleneck represents lost time for the whole system
Increasing the capacity of a non-bottleneck station is a mirage
Increasing the capacity of a bottleneck increases the capacity of the whole system
Effective capacity at a station is increased by decreasing the process time.

8. Theory of Constraints
Five-step process for recognizing and managing limitations
Step 1: Identify the constraint
Step 2: Develop a plan for overcoming the constraints
Step 3: Focus resources on accomplishing Step 2
Step 4: Reduce the effects of constraints by offloading work or expanding capability
Step 5: Once overcome, go back to Step 1 and find new constraints