Researchers from Hanyang College have developed a novel DLP 3D printing technique that harnesses overcuring to supply gecko-inspired gentle actuators. Printed in Microsystems & Nanoengineering (April 2025), the method gives improved wafer dealing with and factors to broader functions in gentle robotics and biomedicine.
The workforce, led by Sooheon Kim and Hongyun So, exploited the overcuring phenomenon, normally seen as a defect, to create anisotropic microstructures that mimic the pure adhesion capabilities of gecko toes. These buildings, produced with out complicated lithography, reveal managed directionality in adhesion and detachment, superb for delicate surfaces like silicon wafers.
Turning a flaw right into a function
In conventional DLP 3D printing, every layer of an object is fashioned by exposing a liquid photopolymer resin to patterned UV gentle, triggering a chemical response that solidifies the resin the place gentle is concentrated. Nonetheless, as a result of optical properties of the resin and the scattering or transmission of sunshine past the goal layer, unintended curing, generally known as overcuring, can happen in adjoining areas, typically resulting in function distortion or lack of decision. Relatively than treating this as a flaw to be mitigated, the researchers strategically embraced the phenomenon. By exactly tuning publicity time, gentle depth, and layer geometry, they manipulated the depth and course of UV penetration, inflicting components of the construction to remedy asymmetrically.
This managed overcuring results in the spontaneous formation of tilted, anisotropic microstructures from in any other case symmetrical CAD fashions, remodeling a passive side-effect into an lively design instrument. The result’s a simplified and scalable technique to supply practical microstructures with excessive repeatability, eliminating the necessity for complicated CAD modifications or secondary fabrication processes.
course of. Picture through Kim et al., Microsystems & Nanoengineering, 2025.
Testing and Efficiency
The anisotropic pillars fabricated through managed overcuring had been employed to supply PDMS-based gentle grippers by way of a double-casting course of. These grippers exhibited robust, reversible adhesion on clean surfaces, reliably lifting a variety of check objects, together with 4-inch and 8-inch wafer analogs and heavy glass dishes, as much as 165 g in weight, utilizing solely minimal mechanical enter.
Finite ingredient simulations evaluating commonplace 3D printed buildings to the overcured designs revealed a discount of as much as 18.7% in most von Mises stress beneath loading circumstances. This means that the smoother surfaces and steady geometry of the overcured pillars scale back stress concentrations sometimes discovered at layer junctions in additive manufacturing. In consequence, the grippers confirmed improved structural sturdiness, withstanding repeated deformation throughout gripping and launch with out important degradation.
Sturdiness exams additional validated the robustness of the adhesive surfaces. After deliberate mud contamination, the adhesive power initially dropped to near-zero however was restored to 96.78% of its authentic worth following easy cleansing with isopropyl alcohol, demonstrating reusability in sensible environments. Moreover, beneath a preload of 9 N, the grippers maintained constant efficiency throughout ten consecutive adhesion-detachment cycles, highlighting the reliability of the overcuring-based anisotropic design in repeated-use eventualities.
Past Robotics: A Platform for Useful Microstructures
Whereas the rapid utility is concentrated on wafer dealing with, the implications of this managed overcuring method prolong nicely past gentle robotics. By deliberately manipulating gentle publicity throughout DLP printing, the method permits the fabrication of geometrically complicated and directionally biased microstructures in a single print step, with out the necessity for lithography or post-processing. This opens the door to novel functions in microfluidics, the place exactly tilted or constricted pathways may regulate fluid stream passively, enabling the design of good channels for lab-on-a-chip diagnostics or autonomous chemical processing.
In filtration techniques, the flexibility to create buildings with gradient porosity could possibly be harnessed to develop membranes able to selective particle seize or variable stream resistance, probably helpful in biomedical implants or environmental monitoring. Equally, pressure-sensitive valves or self-regulating stream elements could possibly be created by domestically adjusting overcuring depth and orientation, permitting buildings to mechanically reply to inside stress or temperature adjustments with out requiring digital management techniques. These potentialities counsel a future the place the overcuring phenomenon, as soon as thought of a printing flaw, may turn into a cornerstone for practical microstructure engineering in biomedicine, wearable gadgets, and microelectronic packaging.
Biomimetics and Additive Manufacturing
Biomimetic design is more and more being thought of in design for additive manufacturing, enabling researchers to duplicate complicated pure capabilities by way of engineered supplies. Again in 2021, scientists from Zhejiang College used 3D printing to recreate the layered microarchitecture of cuttlefish cuttlebones, leading to light-weight but extremely impact-resistant buildings that might inform next-generation protecting gear or aerospace elements. In one other instance, researchers developed a way to supply safer, structurally coloured 3D printed components by mimicking butterfly wing nanostructures, avoiding the usage of poisonous pigments. Extra not too long ago, Harvard scientists 3D printed biomimetic blood vessels with helical stream patterns impressed by actual arteries, exhibiting promise for vascular grafts and regenerative medication. The usage of overcuring in DLP to create anisotropic adhesive surfaces modeled after gecko setae matches squarely inside this rising discipline, pushing biomimicry past visible resemblance into practical emulation.
What 3D printing tendencies do you have to be careful for in 2025?
How is the way forward for 3D printing shaping up?
Subscribe to the 3D Printing Trade publication to maintain up with the newest 3D printing information.
You too can observe us on LinkedIn and subscribe to the 3D Printing Trade Youtube channel to entry extra unique content material.
Featured picture exhibits gecko-inspired anisotropic gentle gripper floor fabricated utilizing DLP 3D printing. Picture through Kim et al., Microsystems & Nanoengineering, 2025.
