A new 3D fabrication technique uses holograms to create objects in just a few seconds. This method, developed by researchers from EPFL and the University of Southern Denmark, promises a revolution in the field of volumetric printing.
3D object created from a hologram.
© LAPD EPFL
Traditional tomographic volumetric additive manufacturing (TVAM) uses laser light to solidify resin in a rotating vial. However, this method is inefficient, with only 1% of the projected light contributing to the formation of the object. Researchers have therefore developed a more efficient approach, using holograms to improve resolution and reduce the energy required.
By projecting a three-dimensional hologram of the desired shape, researchers were able to precisely control the phase of the light waves. This innovation allows for better light efficiency and improved spatial resolution, making it possible to create 3D objects in less than 60 seconds.
The HoloTile technique, invented by Professor Glückstad, plays a key role in this advancement. It allows multiple holograms to be superimposed to eliminate speckle noise, thereby improving the quality of the projected images. This method is particularly suited for printing with bio-resins and cell-laden hydrogels.
Maria Isabel Alvarez-Castaño, a student at EPFL and lead author of the study, highlights the importance of the self-healing property of holographic beams. This characteristic is essential for biomedical applications, enabling the bio-printing of full-scale models of tissues or organs.
The team now aims to double the efficiency of their method. With computational improvements, the goal is to fabricate objects by simply projecting a hologram onto resin, without the need for rotation. This simplification could pave the way for high-volume, low-energy volumetric manufacturing processes.
- A 405 nm single-mode laser diode is collimated and expanded to cover the active area of a DMD.
- A Fourier lens reconstructs the hologram in its Fourier plane, located inside the rotating photoresin container.
- Holographic projections are synchronized with the rotation of the container.
- Two cameras monitor the holographic reconstruction and polymerization process.
- Benchy boat model (Copyright CC) generated with Wolfram Mathematica® 13.1.
Professor Moser concludes that the holographic addition to TVAM technology opens the door to a new generation of volumetric additive manufacturing systems that are more efficient, precise, and faster. This advancement is a significant step toward creating complex objects with unprecedented precision.
What is tomographic volumetric additive manufacturing (TVAM)?
TVAM is a 3D printing technique that differs from traditional methods in its unique approach. Instead of building objects layer by layer, it uses laser light to solidify resin in a rotating vial. This method allows objects to be created in just a few seconds, offering a fast alternative to conventional 3D printing techniques.
However, the energy efficiency of traditional TVAM is a major issue, with only a small fraction of the projected light contributing to the formation of the object. Researchers have therefore sought ways to improve this efficiency, leading to the use of holographic techniques for better precision and a significant reduction in the energy required.
The key innovation lies in using the phase of light waves, rather than their amplitude, to precisely control the solidification of the resin. This approach not only allows for better spatial resolution but also more efficient use of light, opening new possibilities for the rapid fabrication of complex objects.
How does the HoloTile technique work?
The HoloTile technique, developed by Professor Jesper Glückstad, is an innovative method for generating holograms. It allows multiple holograms of a desired projection pattern to be superimposed, thereby eliminating speckle noise that can otherwise create grainy images.
This technique is particularly useful in the context of volumetric additive manufacturing, where the quality of the projected image is crucial for the precision of the printed object. By eliminating speckle noise, HoloTile improves the fidelity of printed 3D objects, enabling the creation of complex shapes with unprecedented precision.
Another advantage of HoloTile is its ability to make holographic beams 'self-healing.' This means the beams can pass through resin without being deflected by small particles, a feature essential for printing with bio-resins and cell-laden hydrogels. This property opens new perspectives for biomedical applications, such as bio-printing full-scale models of tissues or organs.