A couple of weeks ago we started talking with a furniture factory. I will not give more details yet because we do not have permission to release more information.
However, with a single conversation we knew immediately that this factory is suffering from late delivery of its orders, and from there we made a series of guesses.
The most frequent case is that these factories do not use the time buffer concept to control work in process (WIP), and that is why their capacity fluctuates, making it impossible to estimate delivery dates with sufficient precision. (More details about this concept in https://otif100.com/the-3-keys).
However, in a second conversation, now with the production manager, we learned very valuable things. It was no surprise that the constraint of the process, which consists of four manufacturing steps, was not identified. And from all that conversation, our team deduced where the constraint should be, which in this case turned out to be the second resource.
But that was the first step. The analysis also told us that the first resource could become a bottleneck, but it is very expensive to increase its capacity, because it requires another cutting machine.
Recalling the previous article, about buffers as synchronizers, we designed the operating model for this factory. It turned out to be a combination of time buffer with stock buffer to ensure capacity buffer.
The inventory buffer I'm referring to is not just traditional raw material inventory. In this case it is an inventory of pieces already cut for a set of pieces that are repeated in several models. The supplier charges very little more for sizing, so this inventory is the buffer that builds the capacity buffer in cutting.
The system will look like this: customer orders consume parts already cut from inventory (and replenished with the TOC method), and custom parts (by color or size or shape) that need to be cut on site. The second resource processes both types of pieces, and the last two resources, with extra capacity, finish the furniture, maintaining a low WIP at all times.
Los conceptos son siempre los mismos, pero deben adaptarse a cada empresa como lo hace un sastre con un traje a la medida.
This week we will start with this new design. I hope to report the good results in another article shortly. For now it's just theory ... but it's a good theory!