What’s important to notice is that Little’s Law is a mathematical relationship of averages: Each of the three variables is affecting at least one or both other variables in the relationship. – W = Average amount of time an item spends in the queue – λ = Average arrival rate of items in the queue – L = Average number of items in the queue Mathematically, the relationship between these three variables is the following: The law is based on a connection between three variables the average arrival rate of a queue, the average number of items in the queue and the average amount of time an item spends in the queue. Little’s Law is a theorem for queuing systems which was developed in the 1960s. Is there a tried and tested way to get insights into how our project queues are structured, what faults they have and what we can do to improve them? This is where a digital solution like Intuiflow brings its added value on the shop floor.We all want to make projects more efficient and streamlined. It must be admitted that this is complicated in certain production contexts, for the very reason that it is difficult to see the flow. That’s the role of production teams: To get the flow going as fast as possible – it’s not to maximize the OEE of all resources. All we can do on a daily basis is to get the work to flow through as quickly as possible, to satisfy the customer’s needs, and therefore to finish as quickly as possible the production orders we start. Our staff and their skills are determined. Our machines and their opening times are defined. In the short term, in the operational horizon in which we must make decisions and deal with priorities, our means are defined and fixed. Yes, when we didn’t finish our homework, we would pile up the backlog, and it was hard to keep track. Work-in-progress is increasing, delays are worsening, and priority conflicts are accumulating. We also have non-conformities that are waiting for an analysis and a decision. We also often have products that have been started with missing components, and that are waiting for the complete kit. When you don’t have a line, you can’t see the flow, and very quickly you have things started everywhere that are waiting for the next operation. On a line, the previous part must be evacuated because the next one is coming. We are mainly focused on the efficient use of the means of production, especially since, unlike in-line manufacturing, we do not see the flow. In these contexts, it is easy to lose sight of the real purpose: To finish quickly what you start. Some examples of this type of situation: Machining sequences of complex parts, chemical or pharmaceutical processes that require campaigns, integration of complex systems that include many elements. You are therefore faced with a dilemma: Use specialized and expensive production means efficiently, or finish what you start as soon as possible. The more complex your routings are and the more specialized and expensive your production resources are, the less likely you are to put them in line. The more diversity you have, the more complex it is to set a line. However, this line approach has its limitations and does not apply to all contexts. This is what Henri Ford did with the assembly line of the Ford T. This is the very essence of WIP reduction: we manufacture products in flow, from A to Z, with a sequence that allows for a minimal lead time. we linked the different operations that make it possible to obtain a product as quickly as possible. With the advent of Lean in the 90s, we often put production in line, i.e. You “just” need to reduce the WIP to satisfy the customers with a shorter lead time. If you produce 1000 per day and have 5 days lead time, your WIP is 5000, so if you reduce the WIP to 2000 your lead time will drop to 2 days. The law is simple: the WIP is equal to the throughput multiplied by the lead time. The calculation formula that applies to this is called “ Little’s Law.” When I tell you it’s for the little ones… and the adult ones we’ve become. The term describes what it is: Something that is “in progress” means that it is started but not finished, and so when we were kids, we would have been slapped on the wrist for having lots of things in progress and not much finished… tidy your room and finish your homework please! In financial terms, this translates into reducing the work in progress. The translation into a production environment is simple: When you start working on a production order, bring it to completion as quickly as possible, to deliver a saleable product that generates revenue and satisfies the customer. When I was a kid, my parents used to tell me: Finish what you start before you move on! It’s a simple piece of advice that is still relevant today and yet is largely underrated in the industry.
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