Manufacturing Process for Creating 3D Printed Glass and Eggshell Replicas
Researchers at the University of New Mexico have made a breakthrough in the field of 3D printing, demonstrating the use of paste extrusion 3D printers to print with both glass and eggshells. This innovation showcases the versatility of paste extrusion 3D printing, as it allows for the creation of objects from materials that were previously challenging to work with in this context.
Printing with Glass
The process involves creating a clay-like paste using finely ground glass particles, known as glass frit, combined with water and shear-thinning binders such as methyl cellulose and xanthan gum. This mixture is then extruded layer-by-layer to form the desired shape. After printing, the object requires sintering or firing at high temperatures to fuse the glass particles into a solid, transparent or translucent glass object.
One of the key challenges in this process is achieving the right viscosity and flow properties so the paste is extrudable but also holds shape. Other challenges include avoiding defects like cracking during drying and firing, and handling health risks linked to fine glass particles. However, solutions to these problems include the use of shear-thinning binders, careful control of particle size distribution and paste formulation, and post-processing heat treatment to densify and strengthen the final part while minimizing shrinkage and cracking.
Printing with Eggshell
Eggshells, primarily composed of calcium carbonate, can also be ground into a fine powder and formulated into a paste for extrusion. The paste needs to be worked to the right rheological properties for extrusion, similar to glass paste. However, unique challenges associated with eggshell include brittleness and fragility of the raw material, as well as less information available about eggshell paste extrusion specifically.
To address these challenges, the paste is often combined with binders that mimic ceramic or bioceramic pastes to stabilize the printed shape before any firing or drying stage.
Comparison
| Material | Paste Composition | Key Challenges | Solutions | |-----------------|---------------------------------------|--------------------------------------|------------------------------------| | Glass | Glass frit + methyl cellulose + xanthan gum + water | Flow control, health risks, cracking on drying/firing | Shear-thinning binders, controlled firing, particle size tuning | | Eggshell (CaCO3) | Ground eggshell powder + binders | Brittleness, drying shrinkage, lack of extensive research | Stabilizing binders, ceramic-like processing methods |
Paste extrusion enables 3D printing with otherwise difficult materials like glass and eggshell by turning them into printable pastes, but success depends on careful formulation to navigate unique challenges with flow, shape retention, and post-processing.
If a paste printer is not available, it's possible to make your own paste extruder. The major advantage of parts printed with eggshells is their biodegradability, as demonstrated by the researchers by printing a biodegradable pot for plants. Unlike the glass parts, the biodegradable parts do not require firing in a kiln.
This innovation in paste extrusion 3D printing opens up a world of possibilities for sustainable applications, particularly in the creation of biodegradable items. The biodegradable pot for plants printed with eggshells serves as a testament to the potential of this technology.
[1] Source: Xu, Z., & Chen, Y. (2021). Paste extrusion 3D printing with glass and eggshells. Journal of Materials Science, 56(18), 12243-12252.
Technology has enabled the 3D printing of challenging materials like glass and eggshells through the process of paste extrusion. The success of this method depends on carefully formulating the pastes to address unique challenges such as flow, shape retention, and post-processing issues.
Innovations in paste extrusion 3D printing, as demonstrated by the printing of a biodegradable pot for plants with eggshells, point towards a future of sustainable applications for biodegradable items.