We’ve written a lot on this blog about what throughput is and the steps you can take to maximize it (download the guide). In this article, we’ll look at the issue through a different lens: manufacturing throughput time.
What is manufacturing throughput time?
Manufacturing throughput time, aka cycle time, is how long it takes to turn raw materials into finished goods. For example, if it takes 3 hours to from the time you put all of the granola ingredients into the mixer to the time that the first sealed box of granola bars is ready to leave your facility, then your throughput time is 3 hours.
Throughput time is a common key performance indicator because it gives you a measure of the efficiency of your process. It’s also a useful place to start if you’re looking to increase production. The longer it takes products to go from start to finish, the fewer products you can process in a given period of time. Conversely, you can increase your production by decreasing your throughput time (the other option is to run your equipment longer, but if you’re like many manufacturers, you’re already maxed out in terms of resources such as labor).
Throughput time has four components:
- Processing time — This is the time dedicated to the process of manufacturing. In the granola bars example, the mixing, baking, cooling, cutting, and packaging all fall under processing time.
- Inspection time — This is the time dedicated to quality control and inspection, such as visually inspecting the granola bars to make sure they’re all the right size and shape before they head to the packaging equipment.
- Move time — This is the time dedicated to moving products around the facility, such as between machines and from the production area to the warehouse.
- Wait time (or queue time) — This is the time products spend waiting to be processed, inspected or moved. Wait time also happens when a machine on your line goes down, causing a backlog or, in the worst case scenario, downtime for the line as a whole.
Add them all up per unit of product and you get your throughput time.
Throughput time = Processing time + Inspection time + Move time + Wait time
Note that the only value-added time in this equation is the processing time, i.e., the time spent actually manufacturing the product. The rest of it is time spent on administrative and logistical activities.
That doesn’t mean the non-value-added time is all created equal. Some of it is absolutely necessary — like quality control inspections. But a lot of it isn’t; namely, the time dedicated to waiting.
In many manufacturing processes, the majority of a product’s time is spent either being processed or waiting to be processed. In our experience, wait time is typically equal to and sometimes even longer than processing time. That means manufacturers are spending just as much or more time on non-value-added activities than on value-added activities. This may sound like a suboptimal state of affairs, and it is! But that means it represents an opportunity — by shortening your wait time, you can decrease your overall throughput time, which will give you room to increase your production.
There are multiple ways to reduce the wait time in your process depending on what’s causing the wait time in the first place. In our experience, the vast majority of wait time in any process is caused by machine downtime. This is good news because it’s the easiest problem to fix!
In most cases, when one machine goes down, it takes the entire line down with it. The upstream machines have to stop sending products, and the downstream machines become starved of products. The result is that machines that could be performing value-added processing activities instead are forced into a non-value-added state. Every minute this occurs costs your company money.
The solution is to decouple the broken machine from the rest of the line so that the working machines can remain in processing time while the machine that’s causing the bottleneck gets back up and running. You can do this by adding accumulation systems before and after the bottleneck to create buffers. These buffers ensure that no machines on your line are just sitting around idle — if they’re in working condition, they’re being put to work!
We’ve covered how buffers work in previous articles, and we won’t rehash it all here. To learn more, scroll down to the last section of our comprehensive article “What Is Throughput? (And Why You Should Care).”
If you have questions, or would like to discover how buffers can help you reduce your throughput time, contact us.