Where does the concept of the Green Wave come from?
Dominique Bourgoin: What we are going to talk about is the result of a collaboration between Azap and the consulting firm Diagma, an expert in Supply Chain. The green wave generally refers to a traffic control technique for vehicles traveling on a road with several successive intersections. These intersections are equipped with traffic lights. The principle is as follows: a car driving at the speed of the wave will see the lights turn green as it approaches. For Parisians, the typical example of a green wave is the Boulevard Saint-Germain. With all the lights green, it takes 6 minutes to cover the 3 km at a speed of 30 km/h. Our Green Wave project uses this principle to plan production.
What is the link between traffic flow and production flow?
DB: In the Green Wave, we draw an analogy between cities and factories. The industrial tool is likened to a city, in which each machine can be seen as an intersection. And each production line is a route through the city. Very often, production planning is done in successive stages of product transformation. Once the first transformation is completed, the semi-finished product is stored, waiting for the next machine to be available. As soon as that machine is available, production continues. And again, stock is built up while waiting for the next transformation. The goal of the Green Wave is to plan the flow so that the transformation steps happen continuously, without waiting and without stock. In fact, it’s about reducing the production lead time to the sum of operational times. The Green Wave will thus plan the production path to meet demand, eliminating delays.
I understand the concept of the Green Wave, but could you explain how it applies to production?
DB: The Green Wave is based on the concepts of “virtual lines” and “repetitive patterns.” The principle is to create synchronized virtual production lines. These are sequences of manufacturing steps that minimize production delays and allow for the completion of a product (finished or semi-finished). We call them “virtual” lines because it’s not about physically moving machines around the workshops. Instead, the goal is to establish a synchronized production schedule for these virtual lines. But the idea doesn’t stop there. In fact, the virtual lines compete with each other regarding machine availability. An important part of the methodology is to identify incompatibilities between these virtual lines. The aim is to create a repetitive production schedule to meet demand. For example, for the production of decorated glasses, we would decide that a particular family of bottles will be launched every Wednesday. Another line of bottles will be launched every other Monday. And so on for all requested products. It’s worth noting that this approach is generally applied to products with very high volume flows. This method will thus address about 80% of the demand for larger products. The remaining products will be incorporated day by day, and possibly by order, into the pre-established schedule.
What approach should be followed to define the Green Wave virtual lines and repetitive patterns?
DB: To determine the virtual lines and repetitive patterns of the Green Wave, we have established a methodology in four phases:
- Mapping the production flows
- Identifying the Green Waves or virtual lines
- Identifying the repetitive patterns of Green Waves
- Dynamic modeling, which incorporates uncertainties and quickly simulates a large number of real schedules to choose the most robust pattern.
What results can be expected from the Green Wave?
DB: The results are numerous. The Green Wave helps reduce manufacturing lead times and work-in-progress inventory. It can also reduce investment needs through better utilization of available industrial tools. Additionally, it brings peace of mind to manufacturing teams by stabilizing the plan for a certain period. When automated, the optimization process can be revisited if parameters change significantly.
More concretely, in biochemistry, the Green Wave has shown that production can be increased by 18% while reducing lead times twelvefold (1 month instead of 12). This leads to an increase in revenue, gross margin, a reduction in CO2 emissions, and the possibility of delaying investments.
Similarly, in glass bottle manufacturing, the Green Wave has reduced production lead times from 6 months to 1 month, allowing for lower work-in-progress inventory, improved cash flow, and increased peace of mind.
Finally, at a perfume manufacturer, synchronizing the manufacturing and packaging flows made it possible to systematically empty tanks to free them up, reducing the number of tanks needed by two-thirds for around twenty fragrances.
Dominique Bourgoin, Founder of AZAP,
presents the concept of the Green Wave applied to production flow planning.
To better understand the “Green Wave” methodology and see examples of its results, watch the presentation video below: https://vimeo.com/966840117?share=copy
