A team of researchers at EPFL in Switzerland has unveiled a new 3D printing method that could transform how metals and ceramics are made.
Their approach produces objects that are far denser and stronger than those made with current techniques—overcoming problems that have long limited the use of 3D printing for advanced materials.
Traditional 3D printing methods, such as vat photopolymerization, work by pouring a light-sensitive resin into a vat and then hardening it with lasers or UV light to create the desired shape.
While this method is effective for making polymers, it is far less successful for creating metals or ceramics.
To get around this, some techniques convert printed polymers into tougher materials.
But, as Daryl Yee, head of EPFL’s Laboratory for the Chemistry of Materials and Manufacturing, explains, “These materials tend to be porous, which significantly reduces their strength, and the parts suffer from excessive shrinkage, which causes warping.”
The new method, described in Advanced Materials, takes a very different approach.
Instead of starting with metal-containing resins, the EPFL team first creates a 3D scaffold using a simple water-based gel, known as a hydrogel.
This blank structure is then infused with metal salts. The salts are chemically converted into nanoparticles that spread throughout the gel.
By repeating the process several times, the researchers can build up a high concentration of metal inside the structure.
After five to ten “growth cycles,” the final step involves heating the material. This burns away the remaining gel, leaving behind a finished object that keeps the original shape but is now made of metal or ceramic. The result is a part that is unusually strong and dense, with far less shrinkage compared to older methods.
The versatility of the process is another advantage. Because the hydrogel is infused with metal salts only after printing, the same base structure can be turned into different types of materials, including composites, ceramics, or metals like iron, silver, or copper.
To demonstrate the technique, the researchers fabricated intricate 3D shapes called gyroids. When tested with a universal testing machine, these structures withstood pressures 20 times higher than those produced with previous methods, while shrinking only 20 percent instead of the 60–90 percent seen before.
The potential applications are wide-ranging. The method could be used to make complex, lightweight, and durable structures for sensors, medical devices, or energy technologies. For instance, metals with high surface areas could improve cooling in energy systems, while strong, porous structures could advance fuel cells and catalysts that convert chemical energy into electricity.
Looking ahead, the team hopes to adapt the process for industrial use by increasing material density and making production faster. They are already testing robotic automation to cut down the time required for multiple infusion steps.
As Yee summarizes, “Our work not only enables the fabrication of high-quality metals and ceramics with an accessible, low-cost 3D printing process; it also highlights a new paradigm in additive manufacturing where material selection occurs after 3D printing, rather than before.”
Source: KSR.
