[EN] How to reduce your LT with production scheduling?

When you start thinking about production lead time reduction your first thought is always to go for production process improvement. Value Stream Mapping, Kaizen events, setup reduction batch, and all other types of activities that could drive you to the required result. Not very often is the approach to use pure production planning methods to achieve lead time reduction results. The reason why is that first, it is not always easy and not always visible. In this article, I will present a couple of methods that could be considered to reduce production lead times without changing the manufacturing process itself.

Method 1 – Batch size

Well known fact that LT is longer if the batch size is bigger. More pieces to produce results in a longer time required to do so. In many organizations where products are manufactured in batches, there are always some products where you can modify lot size to get better lead time results. Of course, a lot of factors must be considered like process limitations or economical batch size logic. But you always can choose if your priority is the lead time even if the cost of single products will be higher. It always must be considered in a broader business case perspective and always worth checking if reducing batch sizes could be beneficial for your organization.

Method 2 – Priority queening

Especially in non-line production environments where you have multiple independent work centers. If you will analyze your schedule and network carefully you will be able to identify at least a few products that if you will prioritize them on a specific workcenter you can get better LT results without affecting others. Below you can find a very simplified example that shows how it is possible.

What we did we just prioritized Product 2 on WC2 what caused that queue time got reduced to 1. Product 1 remains the same as in this example it had to wait longer on WC2 but it results in that queue on WC was shorter so there is no impact on total LT.






Real-life is not that simplified but if we will look carefully, we could always find some opportunities for benefits if we will play smart with priorities.

Method 3 – Load leveling

Here we will talk again about queue times. It is always waist but there are few items that we should focus on to reduce them significantly. One of them is level loading. As we know queues are the issue for bottleneck workcenters and as we know as well the heal for bottlenecks queues is level loading. So, if we will schedule our production with careful analysis and simulation for our bottlenecks, we can adjust the plan to minimize queue time to a minimum. Here again, we need to be careful because level loading could create some inventory issues as usually when we are trying to level load some pick in demand, we are usually pulling schedule to the left what still support delivery on time but creates extra inventory on finished goods stock. I will elaborate more about level loading and finished goods inventory challenges in a separate article. But… regardless of inventory issues if manufacturing lead time is our priority this is a good method if queuing time is our issue.

Method 4 – scheduling for setup optimization

In systems where setup is a significant portion of lead time, it is another aspect where you should focus your scheduling optimization. Starting from the first step by creating a setup matrix: a document that describes what setup time you need if you are switching from product A to B, A to C, B to A, C to A, etc. Then using this setup matrix in your scheduling algorithms you can save a lot of time on the lead time, just by scheduling workorders in the right way.

There are more methods like that that you can use to reduce your production lead time in most of the cases without any investments just by putting more intelligence into your production scheduling methodologies. Often its could be challenging especially when you deal with complex networks and dozens of hundreds of products. Then some more advanced methodologies should be used to achieve your optimum schedule. But good information is that most of the issues could be resolved by using spreadsheet software if you will combine it with a smart specialist that loves numbers, algorithmic problem solving, and some VBA programming. The smartest solutions that give you the best benefits are not always the most expensive ones.



If you want o to learn more about how to implement ideas described above or want to discuss more with others contact me at pawel.birecki@live.com

 

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