Tennessee University (UTK) and Oak Ridge National Laboratory (ORNL) scientists have developed a new process to increase the strength of 3D printed materials by 200%.
According to the scientists, the UV-based process helps strengthen bonds of 3D printed materials to withstand more transverse stress than ever before.
The process makes use of the same Fused Deposition Modeling (FDM) technique that’s widely used to print prototypes, molds of industrial processes, and tailored parts across many industrial fields.
In FDM, a filament is passed through a heated nozzle and deposited layer by layer to create a structure. Oftentimes, this weakens their sturdiness, resulting in brittle parts.
“There are about a half dozen methods of 3D printing, and a lack of layer adhesion is a problem in all of them,” intones UTK professor Mark Dadmun.
“This means that many of these materials are brittle, so they can’t handle much strain before they break.”
Dadmun and his team became interested in this problem when a 3D printed car was produced at ORNL.
“While this was an amazing accomplishment, those cars are not actually drivable because they have weaknesses. If there were ever a crash, these cars would splinter,” notes Dadmun.
These weaknesses are the result of poor layer adhesion due to the bulky nature and minimized interactions of polymer chains between layers.
Dadmun and his team have now found a solution to remedy this problem:
“We found that making chemical bonds across the layers of printed product would strengthen the item, because the molecules are now bonded together rather than being in layers where the molecules are just floating by each other.”
In the new process, chemical bonds are formed when a UV light is applied during printing.
The UV starts a reaction that bonds the printing material, overcoming the problem and creating stronger materials.
According to the scientists, the new method can be easily implemented and offers improvements in FDM for multiple materials.
Image and content: University of Tennessee, Knoxville