3D printing inks are becoming quite sophisticated in their applications within 3D printing. For example, these 3D printing inks sometimes use powders that are converted to a gel and sometimes have gels already developed. However, gels are now being developed that allow parts to be created via 3D printing with very unique properties.
At Dartmouth College, researchers have been working on a process that utilizes heat to change the arrangement of the molecular rings in a chemical chain for 3D printable gels. The gels have a variety of functional properties and can subsequently create different forms with different elasticities and stiffness.
Chenfeng Ke, left, assistant professor of chemistry, and Qianming Lin, Guarini ’21, develop smart materials for 3D and 4D printing applications in the Ke Functional Materials Group. (Photo by Eli Burakian ’00 and Robert Gill)
Improving Elasticity and Stiffness
Most commonly, 3D printing inks feature uniform molecular compositions. These compositions create printed objects that have uniform properties The uniform and singular property offers a specified elasticity and stiffness. However, users often desire varying degrees of elasticity and stiffness throughout the printed form.
But printing an object with multiple properties is sometimes problematic and challenging. It means that either the 3D printing evolution must be done in parts, or it would just simply not be possible to accomplish through additive manufacturing. However, the researchers at Dartmouth are working with a new gel that allows finished forms to be printed with multiple properties of different stiffnesses and different elasticities.
The chemical and material breakdown of the gel has to do with different polymer chains and control ring distributions from the gel to the finished form. This composition allows a 3D printed form to have different degrees of stiffness and elasticity throughout the object.
Dartmouth demonstrated this by printing a flower with similar chemical compositions but different molecular rings and distributions. As a result, the product had drastically different mechanical strengths - which can be useful in that the different properties allowed the finished printed form to be adaptable to varying degrees of moisture.
A flower printed using a 3D ink produced with the process. Video Source: Dartmouth
Demonstrating Varying Degrees of Stiffness and Elasticity
In the case of the 3D printed flower, they utilize such inks and were able to create a flower that closes when exposed to moisture. Other parts of the printed flower have different degrees of flexibility. These are created by these molecular rings in the printing gel.
Such properties enable soft petals to close, while the more firm parts of the flower provide an underlying stable and inflexible structure for it.
The development seemed subtle. However, the very technology of these printing gels could be quite useful in the future for soft robotics.
Soft robotics are not rigid and rely on different properties for robots to have pliable functionality for greater uses. This comes at an opportune time when soft robotics are an emergent technology being widely adopted. The research that Dartmouth conducted is likely to prove quite useful in the future for soft robotics and other printed forms that will demand more pliable stiffness and different levels of elasticity.
Using Ink to Generate New and Vibrant Colors
The technology of ink goes beyond just the structural properties that it can achieve. 3D printing now is using inks that are able to generate very vibrant and bright colors.
Artists in fact utilize 3D printing as a new medium of art as the 3D printing process allows them to create very intricate compositions that would be otherwise difficult to produce at all. However 3D printing has its challenges in that it requires a very high heat in order for the artist to work with it.
Researchers are now using a new material that enables them to create a very colorful new ink for 3D art printing. The material is made of pigments found in alginate. Alginate is a sugar from seaweed that forms a stable gel without heat.
ArtSea Inks can be applied throughout the printing process using a nozzle to apply different colors, or the material can be colorized prior to printing. (Photo by Andrea Starr | Pacific Northwest National Laboratory)
Normally 3D printers have used petroleum derived raw materials; however this new material forms a viscous gum that is used as a water-soluble base which transforms into a robust hydro gel.
In the past plastics have been available in many colors; however the color spectrum has been limited. With this new product called algenate colors are almost limitless.
When researchers used the algenate to create these new vibrant colors, they were able to control the consistency of the media by adding more or less of different ingredients into the printing gel ink. With the material, the researchers were able to create very lifelike objects in both 3D and 2D using the inks as the color was almost flawless. They also found that the 3D structures printed with this new vibrant ink was able to maintain its stability over time.
3D printing inks are perhaps one of the most innovative areas within 3D printing technology in general. The inks used influence the different properties of the finished form. By so doing they allow and enable numerous possibilities for the application of 3D printing in many different industries and uses.
It's only the tip of the iceberg when it comes to the possibilities that 3D printing ink innovation and emerging technology offers. For now, we'll pay great attention to the ink and all that it produces. Ink is an emergent technology for 3D printing.
