A typical application of 3D printing is modeling, in many cases, you can replace models made of gypsum with this, and you can create even more complex shapes. That is how the idea came: why not to mix gypsum powder into the PLA filament. After several experiments, tests and printings, we created a “gypsum” product group, with Essence, Model and Gypsum products, with increasing gypsum content in this order. These materials – especially Filaticum Model and Gypsum – are filaments that can be easily sanded, cut or even painted with water-based paints. With microscopic images, we can now show you up very closely how a mixture of a mineral and a plastic looks like.
On this picture, you can see an object printed with Filaticum Model then it was cut in half crosswise. Magnification is 60x. At the top of the picture, the melted filament threads can be seen, and you can learn from this picture also, why the surface of the printed objects is “wavy”: the laid-on top of each other filament threads form the “wave”.
The printed layers lie evenly on top of each other, they fully melted together.
Tiny grains can be seen everywhere on the surface, this is gypsum powder used as the main additive.
These grains are much more visible on the following picture where the Filaticum Model filament was cut crosswise. The small spheres on the picture are probably due to the fact that after a while the filament absorbed moisture and the water evaporated during printing. If the cut Filaticum Model filament is examined under an electron microscope, we can clearly see the gypsum grains located as tiny dots in the PLA polymer matrix. This, of course, requires a magnification of two hundred times.
The particle size of the gypsum in this case is micron size. What you can still observe, that the gypsum crystals are homogeneously distributed, they are of uniform size, and they do not form larger agglomerates. This is important because this way the 3D printed object will have a homogeneous surface and on the other hand it will not cause clogging in the nozzle. Thanks to the fine distribution, the objects can be sanded and painted well. And it also results in a semi-gloss to matte finish depending on the printing conditions.
We would like to thank the colleagues of the University of Pécs providing the microscopic images.