Volume 3D printing technology has once again made a significant breakthrough. Thanks to microwave light sources, it is compatible with more materials and can print larger models.
Different from existing SLA, LCD and DLP 3D printing technologies based on photopolymerization, volumetric 3D printing (VAM), also known as “computational axial lithography”, is a new method of photopolymerizable 3D printing. The key to this technology is the combination of materials, rotation and spotlights. The biggest feature is that it is not necessary to accumulate materials layer by layer, but to project light images from different angles in the three-dimensional space of the transparent resin. After several exposures, the object is quickly formed and solidified in the tank.
As early as 2017, Lawrence Livermore National Laboratory (LLNL) launched this instant-moment technology to create complete 3D shapes in seconds using holographic light fields. But the technology still faces some challenges. The resin must be optically transparent or have low absorption capacity so that UV rays can penetrate to the center of the resin, which limits the choice of materials. Additionally, the print size is relatively small, limiting printing to objects within a centimeter range.
Now, the LLNL research team has iterated on this technology and developed a new 3D printing process called “Microwave Volume Additive Manufacturing (MVAM).” By solidifying materials using microwave energy, this technology significantly expands the range of materials available. In a paper published in the journal Additive Manufacturing Letters, LLNL researchers demonstrate the potential of microwaves to penetrate more materials and achieve larger casting sizes than traditional optical VAM technology.
Research shows that microwave energy can penetrate deep into materials, making it particularly suitable for curing opaque resins and resins that add composite materials. Project leaders Saptarshi Mukherjee and materials chemist Johanna Schwartz emphasized that this technology is expected to significantly increase the versatility of 3D printing, enabling the manufacturing of more complex and high-performance parts, even large parts.
Mukherjee said MVAM technology will revolutionize the perception of additive manufacturing, especially in sectors such as aerospace, automotive and nuclear power, where components, although geometrically simple, are large and require a rapid prototyping. MVAM can meet this need.
Additionally, the research team developed a multiphysics microwave beam computational model to optimize energy transfer and curing time while better controlling heat during the printing process. Through experiments, the researchers verified the effectiveness of the model and successfully demonstrated the ability of microwaves to cure various materials, including optically translucent and opaque epoxies.
The experimental results are exciting: using existing 40-watt microwave equipment, curing the resin takes only about 2.5 minutes, and simulation results show that if the power is increased to 1 kilowatt, the Curing time can be reduced to 6 seconds. This speed is close to that of a household microwave oven, which greatly accelerates production efficiency and paves the way for manufacturing large parts. The research team has successfully printed structures ranging from a few millimeters to 20 millimeters and plans to scale them up to the meter scale in the future.
Schwartz added that microwave additive manufacturing technology overcomes the limitations of traditional optical VAM in material transparency and can use a wider variety of materials, redefining the scope of “printable” materials. Mukherjee said researchers are developing antenna array systems based on beamforming algorithms, paying particular attention to ceramic materials. These materials are difficult to print with traditional VAM, but have important applications in high temperature and high pressure environments.
The broad application prospects of this technology cannot be underestimated, and its ability to cure a variety of materials quickly and efficiently will have a profound impact on the aerospace, automotive and medical industries. For example, manufacturers can print complex components with built-in functionality, such as sensors or conductive traces, in a single pass.
With the continued development of MVAM technology, the research team expects that future antenna array systems can further improve the curing efficiency, accelerate mass production, and be able to handle more types of materials. However, there are still challenges ahead in reducing equipment costs, and the research team plans to further optimize the technology in future studies and explore how to push it toward industrial applications.
Mukherjee said the cost of high-power microwave equipment is still relatively high, with the price of a kilowatt-level pulsed microwave amplifier ranging from $50,000 to $100,000. The research team is looking for ways to design or manufacture certain circuits and hardware themselves to reduce costs and prove the feasibility of the technology in practical applications.
In addition to the new research carried out at LLNL, we have previously reported on a team of scientists led by Professor Christophe Moser from the École Polytechnique Fédérale de Lausanne (EPFL), who published a study on volumetric spiral additive manufacturing in the journal Light: Advanced Manufacturing. (VHAM) technological research.
This technology uses Texas Instruments’ DLP7000 chip to solidify the resin after multiple up and down cycles through precise spiral motion and multiple accumulations of light doses, avoiding the need to amplify the projected pattern while allowing the creation of larger objects.
While the above technologies are still in the research stage, Xolo GmbH, a 3D printing startup headquartered in Germany, has successfully commercialized volumetric 3D printing. In 2021, the company launched “xube”, which is considered the first commercial volumetric 3D printer. In February last year, Xolo also received 8 million euros in Series A funding to continue promoting the development of volumetric 3D printing technology.
Moreover, in addition to volume 3D printing, which is considered the future of next-generation light-curing 3D printing, centrifugal 3D printing is also a new technology worthy of attention. According to the Resource Library, Fugo Precision 3D, a California-based 3D printing startup, has just launched the world’s first centrifugal 3D printer, Fugo Model A. This printer uses centrifugal technology to print in a cylindrical cavity at a single speed. of 1 mm per minute and is equipped with 20 lasers to guarantee high precision in all directions.
In fact, the advantages of domestic 3D printing are mainly reflected on the application side, but we also expect more innovative and original 3D printing technologies to appear first in China. Only in this way can we have a more complete 3D printing ecological chain and occupy a more competitive position in the global 3D printing field.
Of course, our country has also made many breakthroughs in photopolymerization technology. Previously, Mofang Precision launched precision light-curing composite 3D printing technology, the core of which lies in the combination and free switching of multi-precision 3D printing optical systems. Low-precision lenses are suitable for rapid printing of large-format samples, while high-precision lenses focus on printing extremely small details, effectively solving the limitations of fixed precision on printing efficiency. impression.
