Yesterday I talked about my new resin 3D printer setup – The Elegoo Mars Pro, Elegoo Mercury Curing Station, and water washable resin.
So how does this all work exactly?
With a traditional 3D filament printer (which is what I’m more used to), plastic (usually ABS) is heated to melting point and is extruded through a fine nozzle to create a 3D shape. Basically each layer is a very detailed etch-a-sketch drawing. As each layer completes, the print bed is moved down a fraction of a millimeter, and the new layer print starts. The advantages to this process is the filament plastic is cheap, the printers are cheap, and they’re relatively easy to use. The major disdvantages are resolution (the quality of the print layer to layer), and time – if you have a larger model, it’ll take longer to print.
Resin 3D printers work on the same general concept, but apply it in a very different manner. Instead of extruding the plastic through a heated nozzle, the raw uncured resin is loaded into a tank or vat. The build plate is lowered into the stationary resin tank and the 3D print layers are added one by one from below. As the layers are added, the build plate moves up instead of down. The layers are created through the use of a high-resolution single color LCD panel (usually 3-4k resolution), with a Ultraviolet (UV) light source. The light for each layer exposes the resin from below, and the entire layer is cured/hardened in one shot. Which means your print time is determined by overall model height, not amount of material used. Basically, other than resin cost there’s no reason not to use the entire build plate for every print. The resolution is also dramatically improved as each layer is substantially thinner than with a filament 3D printer.
The Elegoo Mars in action – the build plate is submerged in the resin tank and moves upwards as each layer is cured on the plate.
Once the resin print is completed, the build plate lifts out of the resin tank and the model is suspended upside down. The build plate is removed, and the excess liquid resin is removed (either using water, or isopropyl alcohol (IPA)). Once the print is cleaned up, it’s then cured again using a curing station. In my case, I’m using the Elegoo Mercury, however lots of options exist. Basically a curing station exposes the entire print to UV light which completely hardens the outside of the print. In theory you could leave the model outside in the sun and it’d work equally well, however I haven’t tried this yet.
One thing to note – the build plate size on resin versus filament printers are one major area where resin is lacking. Generally speaking, resin 3D printers have 1/2 the build plate area of an average filament-based printer. There are of course much larger resin printers, but for the purposes of the article, resin printers can’t print to the same scale that filament printers can.
That’s the printing process in a nutshell – up next, we’ll talk about where to obtain models, and different file formats.