Best practices
Practical case - Optimizing production organization: an in-depth exploration thanks to the "5 Whys" theory
The "5 Whys" theory originates within Toyota's production system, famous for its innovative approach to automotive production. This methodology, also known as the "5 Whys root cause" method, was developed as part of the Toyota Production System (TPS) in order to solve operational problems in a thorough and lasting way.
The genesis of the method dates back to the mid-20th century, when Taiichi Ohno, chief engineer at Toyota, was looking for ways to improve production efficiency and quality. Faced with recurring problems on the production line, Ohno developed the "5 Whys" technique as a systematic tool to analyze the fundamental causes of problems. The idea was not to settle for treating the obvious symptoms, but to dive deep to understand the underlying roots of the problems.
The "5 Whys" works through an iterative questioning process. When a problem is identified, the first question "Why?" is asked to determine the immediate cause. The answer to this question then becomes the basis of the second question "Why?", and so on, until the fundamental cause is reached. The idea is to repeat this process about five times, hence the name of the method. The "5 Whys" encourage a thorough exploration of problems rather than a mere surface resolution.
The practical application of the "5 Whys" takes place in various contexts, ranging from industrial production to project management and everyday problem-solving. The method is particularly effective for dealing with recurring problems, equipment breakdowns, process errors, and other operational challenges. For example, if a defect is found on a production line, the "5 Whys" will make it possible to identify the root causes, such as preventive-maintenance failures or gaps in operator training.
As the continuous-improvement manager in our plant, I am tackling a major challenge: recurring delays in delivering our products to customers. To do so, I decided to apply the "5 Whys" methodology in order to identify the root causes of our site's delay and develop appropriate solutions.
1️⃣ Why do we have delivery delays?
An initial analysis of throughput times against our production routing shows us that the production of work orders is actually launched ahead of need. These delivery delays are therefore due to production times that are too long relative to the targets. There is in particular very high volatility in the throughput times at the machining station.
2️⃣ Why are the throughput times so heterogeneous at the machining station?
By talking with the operators, we find that they have trouble prioritizing one work order over another and tend to take the one at the top of the pile. By diving into the operational details, we identify that the absence of any notion of priority on the work-in-progress creates major inefficiencies.
3️⃣ Why don't our operators prioritize the right products?
We then examine why our operators fail to establish a clear priority on the work-in-progress. We discover that the absence of any notion of priority complicates the task of the operators, who do not have clear indicators to guide their actions.
4️⃣ Why aren't the products at risk of delay prioritized?
By asking the third "Why" question, we investigate why the products at risk of delay are not adequately prioritized. It becomes obvious that many products share the same delivery date, but without a clear indication of the projected delay for each one, the operators lack visibility into which ones truly require particular attention based on what remains to be produced.
5️⃣ Why is there no notion of projected delay for each of the products?
Our fourth question digs deeper by exploring why no notion of projected delay is integrated into our process. It appears that the absence of tools to calculate the projected delay and of effective communication with the operators creates a major gap in our ability to anticipate and manage potential delays.
✅ Solutions and implementation
Guided by these findings, our action plan takes shape. We plan to introduce a priority system on the work-in-progress, to establish clear criteria for identifying products at risk, and to set up a tool to calculate the projected delay for each product. Our research led to a study of a "best-of-breed" scheduling and production-control solution.
In this specific case, Oplit's scheduling and production-control module is a good solution for providing the operators with the necessary visibility by making visible:
The projected delay of each work order according to its progress against the routing
An easy way to visualize fast tracks and emergencies
Transparency on the production of the upstream / downstream stations to anticipate upcoming emergencies and track the proper progress of production
⚠️ The limits of this theory
The advantages of the "5 Whys" lie in their ability to identify the underlying causes of problems, to prevent recurrences, and to foster a culture of continuous improvement. However, it is crucial to recognize the limits of the method, notably its risk of excessive simplification and its dependence on the experience of the people involved. It is recommended to complement the "5 Whys" approach with other problem-solving techniques to ensure a complete analysis.
In conclusion, the "5 Whys" theory has emerged as a powerful and systematic approach to solving problems by tracing them back to their fundamental causes. Its adoption in various fields attests to its effectiveness, making the "5 Whys" a key method in continuous improvement and the proactive management of operational challenges.
