Yesterday, a member of a forum I frequent asked if there was anywhere where to compare pictures of models that were printed at a different resolution. Not knowing of any (though I assume they’re out there), I decided to do my own quick-reference comparison piece. The question was posed in reference to this Hand of the King pin modeled by Hasier Goitia, so I used it as the subject of my experiment.
Before getting to the pictures, I want to clearly define my workflow. I downloaded the model, scaled it to 10 cm long, sliced it with the standard options provided by Simplify3D, then printed with my Flashforge Creator. I’ll touch on the importance of this in a later, but keep in mind that I didn’t post-process the model at all.
My slicer, Simplify3D, offers 3 auto-configured print qualities: Fast, Medium, and High. There are a number of differences between these options, but the main setting of interest here is the Primary Layer Height. If you’re not familiar with layer height, it’s essentially how thick your slicer (in this case, Simplify3D) will cut each layer of the model.
Layer Height Principle
Let’s use my illustration below to demonstrate the layer height principle. Imagine we’re working with a triangular prism (pyramid), and we’re looking at a perfect cross section of the model. That’s illustrated in red. The black triangles show how the slicer would resolve this solid model into layers. It’s obvious how the height of each layer impacts the resolution of the print. The top right figure shows a sliced part that’s roughly approximated with just 4 layers; each layer is 0.40 mm tall. Sliced like this, the model would print very quickly, but it wouldn’t really look like a pyramid. The bottom left figure doubles the resolution by printing 0.20 mm tall layers. It would take 8 of these layers to build up the full pyramid. It’s easy to imagine how this might take longer to print, but the resulting print would look much more like a pyramid. The same benefits (better representation of the model) and downsides (longer print time) hold for the bottom right figure.
As I mentioned, the 3 auto-configurations that Simplify3D offers are Fast, Medium, and High. These correspond to layer heights of 0.30, 0.20, and 0.10 mm respectively (you may also come across these heights expressed as microns, in which case the layers would be 300, 200, and 100 microns thick). I also manually adjusted the settings to produce a model with a layer height of 0.05 mm (50 microns). This model is actually a good candidate to see the differences between layer heights, as the hand and sword both feature shallow contours. The results are below, without having removed the prints from the rafting.
The perceptive reader may have noticed some strange disconnects on the printed models. In fact, this is why I chose to not remove them from the rafting. The .stl that was used to produce these prints wasn’t particularly packaged at “print” quality per se. Simplify3D is capable of making up for some of these shortcomings when slicing, but it can’t overcome them all. I’ll discuss how to go about cleaning up this particular model in a future post.