CONWIP (Constant Work in Progress) is an easy way to establish pull production for custom-made products. Traditionally there is only one large loop for the product. However, there may also be situations where it is sensible to split a longer CONWIP loop into smaller segments. Let’s have a look at the details.
This is the second post on different types of pull production. It features the less commonly known approaches of triangle kanban, drum-buffer-rope, reorder point (surprise, yes, it is a pull system), reorder period (also a pull system), and FIFO lanes. In my previous post I showed you the kanban system and its variant, the two-bin system, as well as CONWIP and the kanban-CONWIP hybrid.
Pull production is one of the most important aspects of lean production. Its key feature is to have an upper limit on inventory that is not to be exceeded. The most well-known way to implement a pull system is by using kanban cards. However, there are many others. In this short series of two posts, I want to give you an overview of the different ways to implement pull systems, and discuss the pros and cons of them.
One of the most significant insights of the Toyota Production System is its concept of pull production. While often misunderstood, the essence of pull production is a clearly defined limit on the work in progress. Push or pull actually has nothing to do with the direction of the information or material flow. But why does this limit on work in progress make so much difference? Why do pull systems vastly outperform push production systems?
One of the key differences in lean production is to use pull production rather than push production. While pretty much everyone knows (at least in theory) how to implement it using kanban, the underlying fundamental differences are a bit more fuzzy. But what exactly is the difference between push and pull? Also, what makes pull systems so superior to push systems?
It turns out that most definitions are going in the wrong direction. Even the names “push” and “pull” are actually not well suited to describe the concept. Neither are common illustrations, including the one here in the upper left.
In my last posts I discussed the basics of CONWIP systems (Constant Work In Progress) and answered some frequently asked questions Part 1 and Part 2 on CONWIP. Overall, CONWIP is a pretty cool alternative to kanban, also establishing a pull system. It has some very valuable advantages, but it also comes with some disadvantages. In this final post of my series on CONWIP, I will shed light on some of these advantages and disadvantages, especially in comparison with kanban, but also with drum-buffer-rope.
In the last two posts I described the basics of a CONWIP system and started with the frequently asked questions on CONWIP, where CONWIP stands for Constant Work In Progress. However, there are some more frequently asked questions that are also important for CONWIP. These I will explain here. The next and final post of this series will discuss the advantages and disadvantages of CONWIP.
In the last post, I started with the basics of a CONWIP system, where CONWIP stands for Constant Work In Progress. However, there are some more frequently asked questions that are also important for CONWIP. These I will explain here.
Initially, I wanted to write one quick post explaining CONWIP. However, as it happens all too often, one post turns out to be not enough. It quickly expands into multiple posts of a series in order to give you a good, well-rounded overview of the topic. Hence, the frequently asked questions will be covered in two separate posts. After that, the fourth and truly final post of this series will discuss the advantages and disadvantages of CONWIP.