How Does Layer Height Affect A 3D Print Strength? (Optimal Height!)


Slicing is a critical part of the 3D printing workflow. This is where a slicer does the heavy lifting of turning your 3D model into G-code your printer can print. Just as importantly, this is where you control the settings that will determine the quality and strength of your print. 

These settings control shell thickness, print speed, retraction, fill density, build plate adhesion, supports, initial layer thickness and of course layer height. 

In this article, we zoom in on layer height. We explain what layer height is and how it impacts your prints. The main goal of this article is to help you figure out how to produce stronger prints.

By the time you are done reading this article, you should know what the best layer height is for your 3D prints.

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Does Layer Height Affect Strength In 3D Printing?

Strength in a 3D print is mostly a factor of the bond between layers. The stronger the bonds the stronger the print. Several tests as well as anecdotal evidence conclude that layer height can affect inter-layer bonding and consequently the strength of a print. 

Layer height is the thickness or height of each layer of filament, powder or resin extruded, sintered or cured in a 3D printer. It is controlled using slicing software and is measured in microns. A micron is 0.001mm thick. 

3D printers have different layer heights. The primary purpose of layer height is to adjust how much detail a print has. The smaller the layer height a printer can use, the more detailed the prints you produce. The standard smallest layer height for most consumer-grade FDM printers is between 50 and 100 microns (0.05 and 0.1 mm).

Stereolithography (SLA) and Selective laser sintering (SLS) can produce prints with finer details because they have smaller minimum layer heights. If you want to improve the resolution or detail in your prints, choose a printer with the smallest possible layer height.

3D PRINTERSTANDARD LAYER HEIGHT (MM)AVERAGE LAYER HEIGHT (MM)
SLA0.025 – 0.10.5
SLS0.08 – 0.120.1
FDM0.5 – 0.40.2
3d Printer Vs possible layer hight

Which Layer Height Gives You The Strongest 3D Prints?

Generally, a layer height that is not too thick or too thin produces stronger prints. Most 3D printers are set to print at between 0.2mm and 0.35mm. However, 3D printing uses a vast array of materials including plastic, powder and liquid resin. Also, printing processes are different between FDM, SLA and SLS. These factors affect print strength more than layer height. 

How Does Layer Height Impact 3D Print Strength? Theories Listed

There are several contradictory theories around why layer height affects build strength. There are those who find greater strength when printing with thicker layers. Others have found thinner layers to produce stronger prints.

A Case For Thinner Layers

Thinner layers would require a shorter distance between the nozzle and print bed. This would mean the material extruded would stay warmer for longer, helping the layers to bond. Also, the increased density of thinner layers would leave smaller gaps between layers. This would possibly increase adhesion.

A Case For Thicker Layers

Thicker layers mean you print fewer layers. In this case, the theory is since there are fewer layers, there are fewer points at which your print could fail. The technical term for this is the statistical size effect. Source

Nozzle Size And Layer Height

Another factor to consider is the relationship between nozzle diameter and layer height. Nozzles range from 0.1mm to 1mm diameter. Most 3D printers use a 0.4mm diameter nozzle.

The diameter gives you control over the layer height. A wider diameter allows you a larger layer height. You can adjust the relationship between your nozzle and layer height using the 80/20 rule. 

Your maximum layer height should not exceed 80% of your nozzle diameter. Your minimum layer height should not go below 20% of your nozzle diameter. If you were using a standard 0.4mm diameter nozzle, your layer height would therefore be between 0.08 and 0.32. 

Researchers did a study on the effect of nozzle size and layer height on print strength. They tested nozzle diameters of 0.4mm, 0.6mm and 0.8mm at different layer heights. The results suggested that increasing nozzle diameter and layer height reduced the strength of a print. Source

What Is A Good Layer Height For PLA?

0.1mm and 0.2mm is the typical layer height for PLA. This depends in part on the nozzle size. A larger nozzle diameter allows for a wider range in terms of layer height. Generally, for a nozzle diameter of 0.4mm, a layer height of between 0.1mm and 0.2mm gives a good balance of speed and detail. 

A good layer height depends on how fast you want to print, how much material you want to use and how detailed you want your prints to be. 

If you are looking to print faster, for example if you’re making a rough prototype, then you will want to increase the layer height or use thicker layers. Note that this sacrifices detail for speed, however. For more on this, check out our post “Does Slowing Down Print Speed Increase Quality? Influencing Factors!” 

In a case where you need a more accurate print with finer details, reduce the layer height and use thinner layers. This will produce a print with a higher resolution but it will also result in a slower print. 

If you are looking to reduce the material you use, for example if you are running low on filament, then you want to use thicker layers since it extrudes less material. 

What Is The Best First Layer Height In 3D Printing?

A layer height of between 0.2mm and 0.3mm with a 0.4mm diameter nozzle has lower chances of print failure. It’s worth considering making the first layer slightly thicker than the rest of the model. This is particularly important for prints with overhangs or complex shapes.

The first layer of a 3D print is possibly the most important. It is the foundation or the base on which the rest of your print is built. A slightly thicker base will give you a stronger foundation. 

sherifjallad

I am a very well experienced techie civil engineer who's extensively interested in 3D printing technology and even more captivated by the potential of 3D printing livable structures

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