Understanding How Your Markforged 3D Printer’s Hardware & Software Components Contribute to its Performance
When reviewing a 3D printer, resolution, nozzle diameter, layer height, and accuracy are usually the most considered metrics. All of these figures, as is typical with 3D printer specs, are in units of millimeters (or occasionally, in microns). But these figures share more than just units – they are all intimately tied to each other. Let’s define each one first to understand how your 3D Printer’s hardware & software components contribute to its performance.
Layer Height
Resolution
Resolution in the digital world is in units of pixels or DPI (dots per inch). For instance, the common 16:9 widescreen aspect ratio television in 1080p in your house is characterized by 1,920 pixels horizontally and 1,080 pixels vertically. Now, in 3D printing, we are operating in 3 dimensions (XYZ), not 2 dimensions (XY) like the television, so we add another figure for the Z-axis. Also, unlike the television, 3D printer resolution is not in terms of pixels, rather it is in millimeters (or microns, as previously mentioned). Therefore, 3D printer resolution is controlled predominately by stepper motor precision with nozzle diameter contributing.
Nozzle Diameter
Simply the diameter of the nozzle opening at its tip, this metric determines the width of the molten plastic extruded, or bead width (the height will be discussed later). Markforged uses nozzles with a 0.4 mm diameter, the most common size, but 0.2 mm, 0.6 mm, and 0.8 mm are not uncommon. So, you can expect the bead width to be approximately 0.4 mm. The bead width helps determine the minimum feature size in the XY plane. This is what is meant by nozzle diameter contributing to resolution.
Layer Height
We now know the bead width is predetermined by the nozzle diameter, so what controls the height, resolution’s Z-axis figure? You might be surprised to learn that you do! In the printer’s slicer, Eiger for Markforged printers, layer height can be adjusted. Layer heights of 0.05 mm, 0.1 mm, 0.125 mm, and 0.2 mm are available on Markforged printers, the latter 3 being commonly used across all FFF printers. Intuitively, a smaller layer height will result in higher Z-axis resolution. A standard rule is layer height should never exceed 75% of the nozzle diameter. So, your choice of layer heights is a function of nozzle diameter. In other words, the nozzle diameter helps determine your Z-axis resolution.
Accuracy
Accuracy is the culmination of everything just discussed. Stepper motor performance that defines resolution, nozzle diameter that determines minimum feature size, and the layer height you set all contribute to your 3D printer’s accuracy – how similar your parts are to CAD.
Now that these have been defined, let’s solidify our knowledge with some examples from a Markforged Mark Two.
Being a desktop printer, the Mark Two has a maximum Z-axis resolution of 0.1 mm (the smallest layer height available in Eiger). The industrial printers have a maximum Z-axis resolution of 0.05 mm. Since these high resolutions take considerably more time to print, you will have to weigh if the part geometry requires higher resolutions.
Take the part below; it features a very gentle slope. A larger layer height will result in greater layer line visibility as the slope is broken up into fewer steps. Think about a terraced slope as the large layer height – if we divide those terrace steps smaller and smaller, we will get a smoother slope! The part on the left was printed at 0.1 mm layer height; the part on the right was printed at 0.05 mm layer height.
To better illustrate the terrace analogy, let’s look at this slope’s profile and slice it into layers, simulating Eiger’s slicing workflow. When the taller layers are divided in half, the ends of each layer better simulate the part’s spline curve profile.
Understanding the width of the nozzle and the impact of the layer height on precision and surface finish makes it easier to balance part speed and quality as an additive user. Continue exploring this topic in the next article: Understanding minimum feature size.
