Bottlenecks in a Process
A process is a sequence of interdependent events that consume resources at every phase to transform inputs into outputs, which will later become inputs of futures stages until the final product is completed. The goal of any process is to achieve a constant flow of units while maximizing the capacity of every resource, without overloading them. When a resource has less capacity than the established demand it turns into a bottleneck, a constraint. Goldratt Theory of Constraints calls for identify the constraints a process may have, make it as effective as possible and monitor the process to identify any new constraint that may emerge.
For the past two weeks the process I go through to get ready for work each morning has been under evaluation. The process can be divided into the following stages: waking up, choosing the clothe to wear, taking a shower, getting dressed, fixing my hair, gathering all the things I will take to work, taking my medication and getting out of the house. Based on the data collected during the past two weeks, the entire process has a cycle time of 99 minutes. By analyzing the data, two major bottlenecks were identified in the process: the “waking up” and “getting dress” loops. The following table summarizes the data collected:
Process Stage Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10 Cycle Time
Waking Up 30 45 45 45 45 65 50 45 45 45 46.0
Choosing Clothe 10 11 10 12 10 10 10 15 10 11 10.9
Taking a Shower 15 15 15 15 15 15 15 15 15 15 15.0
Getting Dressed 5 5 7 14 6 5 20 5 5 5 7.7
Drying Hair 6 6 5 5 10 7 6 5 6 6 6.2
Gather Things 5 3 5 8 16 10 4 3 7 8 6.9
Taking Medications 3 1 2 8 1 3 3 2 2 2 2.7
Getting Out 2 3 3 7 2 3 3 5 5 4 3.7
Process (mins) 76.0 89.0 92.0 114.0 105.0 118.0 111.0 95.0 95.0 96.0 99.1
The duration of the waking up stage ranges from 30 minutes to 65 minutes, being 45 minutes the mode of the data set. This stage is considered a bottleneck in the process...