Layer thickness in 3D printing: An additive manufacturing basic

Layer thickness in 3D printing is a measure of the layer height of each successive addition of material in the additive manufacturing or 3D printing process in which layers are stacked. It is one of the essential technical characteristics of every 3D printer; the layer height is essentially the vertical resolution of the z-axis.

Close up of a 3D print displaying layer thicknesses from Selective Laser Sintering (SLS) printing technology

Layer thickness examples

In general, not all 3D printers are technically equal, as there are technological differences that generate different layer thicknesses, some 3D printers generate lower layer height than others. Generally, 3D printers' min layer thicknesses is 16 µm layer height and the max is 150 µm layer height. You are able to change this setting on all 3D printers before beginning the 3D printing process of your 3D file. The printing time required and the results of a smoother surface are also greatly determined by layer height. Here is a summary table of the max and min layer thicknesses for the various 3D printers (like FDM printer, SLA 3D printer etc.) and technologies:

Printer / Technology	Layer Thickness
Professional fused deposition modelling for production (Stratasys, etc.)	0.17 mm to 0.33 mm (0.007" to 0.013")
Office or fablab fused deposition modelling (Makerbot, Ultimaker, etc.)	0.10 mm to 0.33 mm (0.004" to 0.013")
Selective laser sintering (SLS) - (EOS, 3D System)	0.060mm to 0.150 mm
Resin deposit (Stratasys Polyjet)	0.016mm to 0.028 mm
Material binding (3D Systems ZPrinter)	0.1 mm
Stereolithography, DLP, resin hardening by light or laser	0.05 mm to 0.15 mm
Wax deposition by piezoelectric head (Solidscape)	0.005 mm to 0.10 mm

Differences between layer thickness, printing resolution, and size of the smallest detail possible

The layer thickness in 3D printing should not be confused with printing resolution or with the size of the smallest detail possible. 

The print resolution is the size of the printed voxel. In laser sintering technology, it is related to the size of the laser beam, which is typically around 120µm to 150µm.

As for the size of the smallest detail possible, it is based on the strength of the 3D printing materials. Therefore, even though in theory the print resolution (vertical resolution) may allow construction of a 125µm detail on a surface, in reality it isn't strong enough to withstand the cleaning and finishing stage if it has a diameter of 0.5mm to 0.8mm, according to its size.

Relation between layer thickness and 3D printing direction

The impact of a 3D printer's layer height on the print result also depends on the orientation chosen for printing objects. 

In particular, flat surfaces with a weak rising angle relative to the z-axis will be greatly impacted. A staircase effect will appear to the surface finishes no matter what technology is chosen. The printing finishes are impacted either in SLA 3D printing, in FDM printing, even in binder jetting. 

The Batch Control tools, available for orders of more than 20 copies, let you specify the orientation and thus optimise the choices of quality vs. cost of 3D printing. 

Layer thickness, 3D printing speed and the cost of objects

The number of layers required to create an object determines the printing speed and thus the printing time required. The lower the layer thickness, the longer it takes to make a 3D printed object of a given height.

Therefore, an object 1cm high requires 100 layers at 100µm (like on our material, for example White Plastic) or 167 layers at 60µm. This explains the higher cost of 3D printing using the same technology with thinner layers.

Comparisons of the results of different layer thicknesses

For more information about the relation between layer thickness and printing, you can check out this blog post that explains the effect that has the changing of the layer thickness on the printing quality.