What makes PLUTO print
PLUTO is a top-down, DLP powered, stereolitography 3D printer with a lot of built-in features.
But what do these technical terms even mean?
PLUTO utilises stereolithography to formulate the finished objects from photosensitive resins. They are bought in liquid form, and they turn solid if light shines on them in the right wavelength. The trick is that they only solidify (or more correctly called polymerize) in the exact place where the light hits them, everywhere else they remain liquid.
Stereolithography exploits this property and builds up 3D objects by dividing them into layers and exposing every layer of fully liquid resin with the cross section of the part in the correct position. In the end you get a solid 3D object emerging from a tank of reusable, still liquid resin.
The finished parts are much more precise and durable than what you can achieve on any FDM machines.
DLP stands for Digital Light Processing. It is an image projection technology pioneered and marketed by Texas Instruments, which formulates every pixel of the projected image with a miniature (micrometer sized) mirror.
Tilting a mirror to one side lets the light shine out of the optics, tilting it to the other side essentially turns that pixel black.
But why are we talking about image projection when we need to print 3D objects?
DLP based printers use DLP projectors to expose one whole layer (the cross section of the part) at once instead of using galvanometers to progressively scan the area with a laser dot.
Summarized: DLP technology makes the printing process much faster and more efficent.
Stereolithography 3D printers can generally be divided into 2 distinct groups:
bottom-up and top-down machines. PLUTO belongs to the latter and it means, that the actual image of the currently exposed layer is projected onto the surface of a tank filled with the photosensitive resin.
The printing process of PLUTO can be simplified as:
- the build platform submerges below the resin's surface, exactly to the depth of one layer
- the first layer of the part is projected onto the surface, which hardens the resin in the correct form. This layer reaches the build platform and gets attached to it.
- the build platform moves down by the height of the next layer, exposing a fresh, uncured resin on the top of the first layer
- the next layer is projected onto the surface, hardening it and attaching it to the layer below
- the build platform submerges again and this process continues until the part is completed.
By choosing this architecture we reduced the chance of printing failures while making PLUTO simpler and more efficient as well.