Gabriel Lipkowitz

All Publications

• High-resolution stereolithography: Negative spaces enabled by control of fluid mechanics. Proceedings of the National Academy of Sciences of the United States of America Coates, I. A., Pan, W., Saccone, M. A., Lipkowitz, G., Ilyin, D., Driskill, M. M., Dulay, M. T., Frank, C. W., Shaqfeh, E. S., DeSimone, J. M. 2024; 121 (37): e2405382121

  Abstract

  Stereolithography enables the fabrication of three-dimensional (3D) freeform structures via light-induced polymerization. However, the accumulation of ultraviolet dose within resin trapped in negative spaces, such as microfluidic channels or voids, can result in the unintended closing, referred to as overcuring, of these negative spaces. We report the use of injection continuous liquid interface production to continuously displace resin at risk of overcuring in negative spaces created in previous layers with fresh resin to mitigate the loss of Z-axis resolution. We demonstrate the ability to resolve 50-μm microchannels, breaking the historical relationship between resin properties and negative space resolution. With this approach, we fabricated proof-of-concept 3D free-form microfluidic devices with improved design freedom over device material selection and resulting properties.

  View details for DOI 10.1073/pnas.2405382121

  View details for PubMedID 39231205

• Growing three-dimensional objects with light. Proceedings of the National Academy of Sciences of the United States of America Lipkowitz, G., Saccone, M. A., Panzer, M. A., Coates, I. A., Hsiao, K., Ilyn, D., Kronenfeld, J. M., Tumbleston, J. R., Shaqfeh, E. S., DeSimone, J. M. 2024; 121 (28): e2303648121

  Abstract

  Vat photopolymerization (VP) additive manufacturing enables fabrication of complex 3D objects by using light to selectively cure a liquid resin. Developed in the 1980s, this technique initially had few practical applications due to limitations in print speed and final part material properties. In the four decades since the inception of VP, the field has matured substantially due to simultaneous advances in light delivery, interface design, and materials chemistry. Today, VP materials are used in a variety of practical applications and are produced at industrial scale. In this perspective, we trace the developments that enabled this printing revolution by focusing on the enabling themes of light, interfaces, and materials. We focus on these fundamentals as they relate to continuous liquid interface production (CLIP), but provide context for the broader VP field. We identify the fundamental physics of the printing process and the key breakthroughs that have enabled faster and higher-resolution printing, as well as production of better materials. We show examples of how in situ print process monitoring methods such as optical coherence tomography can drastically improve our understanding of the print process. Finally, we highlight areas of recent development such as multimaterial printing and inorganic material printing that represent the next frontiers in VP methods.

  View details for DOI 10.1073/pnas.2303648121

  View details for PubMedID 38950359

• Methods for modeling and real-time visualization of CLIP and iCLIP-based 3D printing GIANT Lipkowitz, G., Coates, I., Krishna, N., Shaqfeh, E. G., DeSimone, J. M. 2024; 17

  View details for DOI 10.1016/j.giant.2024.100239

  View details for Web of Science ID 001167580600001

• Palimpsest: a spatial user interface toolkit for cohering tracked physical entities and interactive 3D content Lipkowitz, G., ACM ASSOC COMPUTING MACHINERY. 2024

  View details for DOI 10.1145/3672539.3686780

  View details for Web of Science ID 001336607900108

• RubiXR: Demonstration of dynamic task augmentation through co-design of interactive 3D content and 3D user interfaces Lipkowitz, G., Spencer, S. N. ASSOC COMPUTING MACHINERY. 2024

  View details for DOI 10.1145/3677386.3688875

  View details for Web of Science ID 001323671000032

• Palette-PrintAR: augmented reality design and simulation for multicolor resin 3D printing Lipkowitz, G., DeSimone, J. M., ACM ASSOC COMPUTING MACHINERY. 2024

  View details for DOI 10.1145/3613904.3642909

  View details for Web of Science ID 001266059703054

• Palete-PrintAR: an augmented reality fluidic design tool for multicolor resin 3D printing Lipkowitz, G., Shaqfeh, E. G., DeSimone, J. M., ACM ASSOC COMPUTING MACHINERY. 2023

  View details for DOI 10.1145/3586182.3616684

  View details for Web of Science ID 001125107000046

• Fluidics-Informed Fabrication: A Novel Co-design for Additive Manufacturing Framework Lipkowitz, G., Shaqfeh, E. G., DeSimone, J. M., Li, W. C., Harris, D. SPRINGER INTERNATIONAL PUBLISHING AG. 2023: 454-466

  View details for DOI 10.1007/978-3-031-35389-5_31

  View details for Web of Science ID 001286432800031

• Printing atom-efficiently: faster fabrication of farther unsupported overhangs by fluid dynamics simulation Lipkowitz, G., Krishna, N., Coates, I., Shaqfeh, E. G., DeSimone, J. M., Spencer, S. N. ASSOC COMPUTING MACHINERY. 2023

  View details for DOI 10.1145/3623263.3623354

  View details for Web of Science ID 001147521200011

• Single-digit-micrometer-resolution continuous liquid interface production. Science advances Hsiao, K., Lee, B. J., Samuelsen, T., Lipkowitz, G., Kronenfeld, J. M., Ilyn, D., Shih, A., Dulay, M. T., Tate, L., Shaqfeh, E. S., DeSimone, J. M. 2022; 8 (46): eabq2846

  Abstract

  To date, a compromise between resolution and print speed has rendered most high-resolution additive manufacturing technologies unscalable with limited applications. By combining a reduction lens optics system for single-digit-micrometer resolution, an in-line camera system for contrast-based sharpness optimization, and continuous liquid interface production (CLIP) technology for high scalability, we introduce a single-digit-micrometer-resolution CLIP-based 3D printer that can create millimeter-scale 3D prints with single-digit-micrometer-resolution features in just a few minutes. A simulation model is developed in parallel to probe the fundamental governing principles in optics, chemical kinetics, and mass transport in the 3D printing process. A print strategy with tunable parameters informed by the simulation model is adopted to achieve both the optimal resolution and the maximum print speed. Together, the high-resolution 3D CLIP printer has opened the door to various applications including, but not limited to, biomedical, MEMS, and microelectronics.

  View details for DOI 10.1126/sciadv.abq2846

  View details for PubMedID 36383664

• Injection continuous liquid interface production of 3D objects. Science advances Lipkowitz, G., Samuelsen, T., Hsiao, K., Lee, B., Dulay, M. T., Coates, I., Lin, H., Pan, W., Toth, G., Tate, L., Shaqfeh, E. S., DeSimone, J. M. 2022; 8 (39): eabq3917

  Abstract

  In additive manufacturing, it is imperative to increase print speeds, use higher-viscosity resins, and print with multiple different resins simultaneously. To this end, we introduce a previously unexplored ultraviolet-based photopolymerization three-dimensional printing process. The method exploits a continuous liquid interface-the dead zone-mechanically fed with resin at elevated pressures through microfluidic channels dynamically created and integral to the growing part. Through this mass transport control, injection continuous liquid interface production, or iCLIP, can accelerate printing speeds to 5- to 10-fold over current methods such as CLIP, can use resins an order of magnitude more viscous than CLIP, and can readily pattern a single heterogeneous object with different resins in all Cartesian coordinates. We characterize the process parameters governing iCLIP and demonstrate use cases for rapidly printing carbon nanotube-filled composites, multimaterial features with length scales spanning several orders of magnitude, and lattices with tunable moduli and energy absorption.

  View details for DOI 10.1126/sciadv.abq3917

  View details for PubMedID 36170357

• Characterization of a 30 m pixel size CLIP-based 3D printer and its enhancement through dynamic printing optimization. Additive manufacturing Lee, B. J., Hsiao, K., Lipkowitz, G., Samuelsen, T., Tate, L., DeSimone, J. M. 2022; 55

  Abstract

  Resolving microscopic and complex 3D polymeric structures while maintaining high print speeds in additive manufacturing has been challenging. To achieve print precision at micrometer length scales for polymeric materials, most 3D printing technologies utilize the serial voxel printing approach that has a relatively slow print speed. Here, a 30-m-resolution continuous liquid interface production (CLIP)-based 3D printing system for printing polymeric microstructures is described. This technology combines the high-resolution from projection microstereolithography and the fast print speed from CLIP, thereby achieving micrometer print resolution at x103 times faster than other high-resolution 3D printing technologies. Print resolutions in both lateral and vertical directions were characterized, and the printability of minimum 30 m features in 2D and 3D has been demonstrated. Through dynamic printing optimization, a method that varies the print parameters (e.g. exposure time, UV intensity, and dark time) for each print layer, overhanging struts at various thicknesses spanning 1 order of magnitude (25 m - 200 m) in a single print are resolvable. Taken together, this work illustrates that the micro-CLIP 3D printing technology, in combination with dynamic printing optimization, has the high resolution needed to enable manufacturing of exquisitely detailed and gradient 3D structures, such as terraced microneedle arrays and micro-lattice structures, while maintaining high print speeds.

  View details for DOI 10.1016/j.addma.2022.102800

  View details for PubMedID 35602181

• Numerical Modelling of Moisture Loss during Controlled Drying of Marine Archaeological Wood FORESTS Lipkowitz, G., Hennum, K., Piva, E., Schofield, E. 2021; 12 (12)

  View details for DOI 10.3390/f12121662

  View details for Web of Science ID 000737528300001