Teaching lasers to self-correct in high-precision patterned laser micro-grooving

(Press-News.org) In International Journal of Extreme Manufacturing, a new laser machining method that dynamically adapts its beam shape is proposed to fabricate microgrooves with complex, highly precise cross-sections—some with a root mean square error decreased to less than 0.5 μm when processing microgrooves with a width of 10 μm.

The technique, developed by researchers at the Southern University of Science and Technology (SUSTech) in Shenzhen, China, could advance the production of microfluidic devices, sensors, and heat dissipation systems by allowing for rapid and scalable manufacturing of custom microstructures.

Laser micromachining has long been constrained by the fundamental limitations of Gaussian beam profiles, which tend to produce simple, U- or V-shaped grooves that fall short of application-specific requirements.

While beam-shaping strategies have allowed researchers to sculpt the cross-sectional shape of laser spots—using, for example, triangular beams to carve triangular channels—the interaction of such patterned beams with materials is complex and often unpredictable.

"Diffraction effects and polarization-related reflections make it difficult to control how energy is distributed during ablation," says Prof. Shaolin Xu, a laser manufacturing expert at SUSTech and corresponding author of the study. "As a result, there's often a large mismatch between the intended and actual groove shape."

To overcome this, Prof. Xu's team developed a model-based adaptive beam-shaping technique that can iteratively refine the laser's profile in response to deviations from a target groove shape. At the heart of the method is a physics-informed evolution model that accounts for beam shape, diffraction, and polarization effects, enabling precise prediction of ablation outcomes.

By simulating groove formation and adjusting the beam shape accordingly, the system converges on an optimal solution—essentially teaching the laser to "self-correct".

In laboratory tests, the method produced microgrooves with a variety of cross-sectional profiles—including triangular, trapezoidal, and semicircular shapes—with root mean square errors below 0.5 μm, a fivefold improvement over conventional techniques. Over 70% of measurement points in even the most intricate grooves fell within ±0.5 μm of the desired profile.

The approach is particularly promising for machining hard-to-process materials such as silicon carbide, and the researchers say future work will extend its applicability across a broader range of substrates.

"Precision and flexibility have often been at odds in laser fabrication," says Prof. Xu. "This work shows they can go hand in hand."

International Journal of Extreme Manufacturing (IJEM, IF: 21.3) is dedicated to publishing the best advanced manufacturing research with extreme dimensions to address both the fundamental scientific challenges and significant engineering needs.

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