On the shop floor it is common wisdom to find the bottleneck based on the inventory. If the buffer is full, the bottleneck is downstream. If the buffer is empty, the bottleneck is upstream. Is this true? My student Carolin Romeser and I spent quite some time verifying this, and found some interesting results. In general it is true, but … the devil is in the details.
Bottleneck
A Critical Look at Goldratt’s Drum-Buffer-Rope Method
Eliyahu Goldratt developed different methods on how to manage production systems. These methods are nowadays known as the Theory of Constraints, or TOC for short. One key method described is called Drum-Buffer-Rope, or DBM for short. Similar to Kanban or CONWIP, it aims to constrain the work in progress (WIP) in the system. There is much discussion on which method is better than the other, although the result often depends heavily on with which method the respective author earns its living. In this post I will present how Drum-Buffer-Rope works, and discuss its advantages and shortcomings.
Bottleneck Management Part 3 – Bottleneck Decoupling and Capacity Improvement
Bottleneck detection and management are important in managing or increasing your production capacity. In the first post of this series I talked about fundamentals and improving utilization. The second post looked at the impact of planning on the overall production capacity. This final post in the series will look at the effect of decoupling and the actual process capacity improvement.
Bottleneck Management Part 2 – Improve Bottleneck Planning
Bottleneck detection and management are important when managing or increasing your production capacity. In the first post of this series, I talked about fundamentals and improving utilization. This second post looks at the impact of planning on the overall production capacity. A third post looks at Bottleneck Decoupling and Capacity Improvement.
Bottleneck Management Part 1 – Introduction and Utilization
In the past I’ve written a few posts with some nifty methods on how to find the bottleneck (The Bottleneck Walk – Practical Bottleneck and The Active Period Method), and some warnings of which methods don’t work. In this post I would like to go into more detail on what to do once you find the bottleneck! Due to the length of this topic, I have split it into multiple posts. This first post gives an introduction and goes into more detail about increasing utilization. The next post talks about planning. A third post looks at Bottleneck Decoupling and Capacity Improvement.
The FiFo Calculator – Determining the Size of your Buffers
In my previous post, I discussed how to Determine the Size of Your FiFo Lane – The FiFo Formula. My preferred method is still an expert estimate. However, if you are interested in the math, here is a small JavaScript calculator that estimates a FiFo size for two processes.
Determining the Size of Your FiFo Lane – The FiFo Formula
FiFo lanes are an important tool to establish a pull system. They are often combined with kanban. However, while there is a lot of information on how to calculate the number of kanban (the Kanban Formula), there is very little information available on how large a FiFo should be. In my last post I talked about why we need FiFo lanes. In this post I want to discuss how large a FiFo should be.
Theory and Practice on FiFo Lanes – How Does FiFo Work in Lean Manufacturing?
FiFo lanes are an important part of any lean material flow. They are a very simple way to define both the material flow and the information flow. In this post I want to tell you why to use FiFo, how to use FiFo, and the advantages of FiFo, as well as show you a few examples of FiFo lanes.