Minimal Layer Time in 3D Printing (and why it matters)

Although 3D printing seems like a pretty simple high-tech process, it’s a blend of art and science. As a result, 3D creators have to finesse their printing techniques to make their models look as clean and polished as possible.

One factor that can affect your prints is the minimum layer time. This term refers to the shortest amount of time it takes for a layer to cool before you can add another layer on top. For example, if the MLT of PLA is 10 seconds, you have to wait 10 seconds between layers. Going faster than that can lead to misshapen and “melted” pieces. 

Because MLT is such a critical component of 3D printing, we will take a closer look at the process and how it works. Here’s everything you need to know about minimum layer time.

What is Minimum Layer Time?

Official Creality Ender 3 3D Printer Fully Open Source with Resume Printing Function DIY 3D Printers Printing Size 220x220x250mm

If you’re familiar with 3D printing, you know that a nozzle prints raw material in layers to create a structure. The process is similar to inkjet printing, except it’s within a 3D space, not on a 2D sheet of paper.

To achieve this effect, the nozzle must heat the material to its melting point so that it comes out smooth and bonds to the layer underneath it. If the nozzle moves too fast, each layer will melt into the other because it doesn’t have time to cool off.

That’s where the minimum layer time comes in. This number reflects the shortest amount of time it takes the material to cool and harden so that you can add another layer on top.

The MLT can change depending on the type of material you’re using.

We’ll discuss the different times later on.

How Does Minimum Layer Time Affect 3D Prints?

There are a couple of ways that MLT can impact your 3D printing process.

First, the printer needs to move at a specific speed to keep the material flowing smoothly. So, if the nozzle moves too slowly, the filament can harden and clog the machine.

Unfortunately, the minimum layer time of your filament might not match the minimum print speed of your device.

For example, the MLT might be 10 seconds while the MPS is six seconds.

The other way that MLT affects 3D prints is that it can create melted and uneven surfaces.

If each layer doesn’t have enough time to cool, they’ll merge with each other, and the combined weight of multiple layers will cause the piece to sag.

Usually, minimum layer time is an issue for thin and tall pieces. Because the printer doesn’t have to move around as much, it will print much faster than if you’re creating a larger part.

In some cases, you might not have to worry about MLT because the nozzle takes longer to move around the piece.

For example, let’s say that it takes 20 seconds to complete a single layer.

If the MLT is shorter than that, each layer will cool off as soon as the nozzle comes back around.

Related: Learn more about layer height

FAQs About Minimum Layer Time

Can I Adjust the Minimum Layer Time Manually?

The answer depends on the machine you’re using. Some printers have an option to set the minimum layer time, while others might not. Keep in mind that the minimum print speed often overrides the layer time.

So, even if you set a higher MLT, the machine might not follow it.

For example, if the MLT is supposed to be 30 seconds and the print speed is only 10 seconds, the device will print at 10 seconds per layer, not 30.

How Does the Minimum Layer Time Change Between 3D Printing Materials?

You only have to worry about MLT when using plastic filaments.

On average, PLA requires 20 to 30 seconds to cool, while ABS takes about 20 seconds max.

If you’re printing with resin, you just have to make sure to use UV lights to harden the material between layers.

Related: Learn more about PLA vs ABS filaments

Will Adjusting the Minimum Layer Time Help Prevent “Melting” and Other Print Imperfections?

Yes, ensuring that your MLT matches your print material can help prevent it from melting. However, you can also use other tactics, such as:

  • Ambient Temperature – Keeping the room climate regulated can ensure that the material cools off faster.
  • Enclosed Printer – These models are more expensive, but they control the temperature better and can avoid overheating.
  • Fans – If you keep a fan blowing on the piece, it will cool off much faster.
  • Heated Bed – These units can maintain a more even temperature during printing, although melting can sometimes still be an issue.

Is the Minimum Layer Time the Same for All Prints Using the Same Material?

No, what matters is the size and shape of your piece. As a rule, taller and thinner prints will have more of a problem than shorter and wider models. The longer it takes for the nozzle to complete a single layer, the less you have to worry about MLT.

Overall, minimum layer time is just one component of 3D printing. Understanding how it works won’t prevent all issues, but it can help you produce more high-quality prints.