Scheduling Mixed Model

Scheduling is not the easiest thing in the world. Some facilities have everything beautifully automated.  Others make you miss the day of figuring out classes by pencil and paper. There’s a lot of erasing. Corso is going to put together a handful of posts talking about scheduling.

If you missed the first post, check out Scheduling Machines & Product. The second post on How and Why You Need To Schedule Operators.

Again, there are many scheduling options including inside your Industrial Control System, ERP, or web based.

There isn’t a easy, this is your solution. If that’s what you’re looking for,  give Dave a call, and let’s have a conversation.

What Is Mixed Model Assembly?

We need to take a step back from scheduling and talk about mixed model assembly. At the most basic level, mixed model assembly takes place when two dissimilar from each other. For production reasons, it’s decided that more than one item is going down the assembly line at the same time.

We’re big example people, so let’s talk about something most people know about: computers. And because they are some of the simplest options Apple’s MacBook Pro. Generally, there are three or four options that separate the base level versus the top of the line. The other dozens or hundreds of parts and assemblies are the same. So your case, your keyboard, webcam, and more.

For this we’ll say there are 2 options going to be run down the line. We’ll call them MBP1 and MBP2. A 1:1 mixed model will look like doing a MBP1, then MBP2, MBP1, MBP2, back and forth down the line. It looks something like this for a single line. This would be if the company had approximately the same sales for both models.

What if a company sold three times the MBP1 model than MBP2? Then we’re talking about a 3:1 Mixed Model Assembly. Again this would look like MBP1, MBP1, MBP1, MBP2, MBP1, MBP1, MBP1, MBP2.

A company could in theory do mixed model at any interval they want. Some facilties also opt to run more than two items on the line at the same time. All of these are options based on your specific needs. The more complex the process, the harder to get right. Corso would be happy to walk you through how we’ve successfully completed this.

What Is Mixed Model Scheduling?

Mixed Model Scheduling is quiet simply scheduling of a Mixed Model Assembly. This takes all of the normal levels of complexity and ramps them up for both scheduling and assembly.

Some items that we must be cognizant:


We need to stay aware of both current inventory levels and the inventory needs of the parts we’re going to run. Now some facilities have enough problems running the same items on a line all day long. If there are issues with the your supply chain, they will come to light. Increasing the complexity of assembly will do this. Please do not let us scare you away from this, we just want you to be aware.

We’ll also want to talk about how you’re getting the inventory to the line. Are you using a Just In Time (JIT) approach? Are you bringing all the stock out and just running? Something in-between?

Bill of Materials

If you’re assembling, you should know what the Bill of Materials or BOM looks like. Now we’re going to correlate the BOM, Inventory, and the actual schedule to make sure we have the stock to run the load.

Hopefully the answer is yes. If the answer is no, then a Corso system will calculate that BOM multiply it by the quantity of the schedule, and then check with the inventory to confirm you can do the entire run. If you can’t, an error, alarm, or something else will occur, so the problem is immediately viewable.

Want to have options of quantity, or other builds also pop up? Ask us and we can help with that as well.

Assembly Line

Assembly lines can be an entire series in and of themselves. For the purpose of Mixed Model Scheduling, you as a baseline need to be able to tell the operators a couple of things. A) What is currently being run which part(s). B) Which part they are assembling. Or Potentially not assembling if they are only installing parts on some of the models.

What are you running? Are you doing Mixed Model Assembly? How are you scheduling?