How to make the chips produced in the cutting process useful?

Compared with other cutting methods, EV-chiseling could generate metallic microstructures with ultra-high aspect ratio, and the cutting chip directly transformed into unique microstructures.

Scientists from Tsinghua University have proposed a novel process to convert the cutting chips into microstructures directly and make the chips useful.

The research, published in International Journal of Extreme Manufacturing, shows how to make the chips produced in the cutting process useful and become a cutting chip player. 

This upends the conventional wisdom about manufacturing cutting chips usually turned into waste after processing. The finding is unexpected and interesting, it's hard to imagine how many chips are disposed of as waste every day; if using our process, the waste could be turned into treasures.

"In principle, this proposed method is the original innovation in the field of processing, and provides a new way of fabricating metallic microstructures," said Jianjian Wang, an associate professor of the Department of mechanical engineering at the Tsinghua University and corresponding author on the study. "In general, this method links the waste-cutting chips and useful metallic microstructures," said Zhiwei Li (Ph. D. student, now at Tsinghua), the first author of the paper.

Microstructures are everywhere if you look carefully at the surface of objects, whether it is the surface of plants (lotus leaves, roses, straw, etc.), or the surface of animal hair, or human skin.

It has been found that such microstructures have special properties such as hydrophilicity, hydrophobicity and antibacterial properties, but so far, it is still a difficult problem to fabricate such microstructures on metal surfaces, and the key is to increase the aspect ratio (height divides width). This is because metal materials are not easy to work with, especially on small scales. 

Cutting is the most commonly used machining method for metal materials. Then Li began experimenting with different cutting methods two years ago, but always failed, "I tried almost every machining method, but the aspect ratio could not be increased," said Li. One day during the discussion, "If we change the feeding direction, would there be a different?" said Wang, "that maybe work, especially changing the feeding direction of elliptical vibration cutting!" said Li. However, the initial experiments were not ideal.

"We believe that changing feeding direction must be useful," said Wang, then they re-designed the processing device and optimised the shooting method, and satisfactory results were finally obtained.

"It is amazing that the chip is completely invisible during the cutting process, and the chip could be found directly into the microstructure through SEM," said Li. Besides, they found that by changing the processing parameters, different kinds of microstructures could be transformed directly through the chips.

"Cutting does not produce chips, chips can be directly turned into microstructures, is it amazing?" said Li. What can these kinds of microstructures be used for? "We are using the processed microstructures to carry out a large number of application experiments, including enhanced heat transfer, anti-icing, antibacterial, etc., and have achieved relatively good experimental results, which can be more widely used in the future," said Wang.

Wang and his lab are working with other scientists around the university to try to understand how the microstructures generate. "There are many problems that need to be further solved, such as the mechanical mechanism of chip transformation and the change of surface structure, which are related to future applications," said Wang. 

Shifting our thinking in research may lead to completely different findings, and trust in our own judgment. "We are cutting chip players, we hope more scientists could join us in exploring the mystery of cutting chips," said Wang and Li.

About IJEM:

International Journal of Extreme Manufacturing (IF: 14.7, 1st in the Engineering, Manufacturing category in JCR 2023) is a new multidisciplinary, double-anonymous peer-reviewed and diamond open-access without article processing charge journal uniquely covering the full spectrum of extreme manufacturing.

The journal is devoted to publishing original articles and reviews of the highest quality and impact in the areas related to the science and technology of manufacturing functional devices and systems with extreme dimensions (extremely large or small) and/or extreme functionalities, ranging from fundamental science to cutting-edge technologies that support the manufacturing of high-performance products involving emerging techniques and breaking the limits of currently known theories, methods, scales, environments, and performance.

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