Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Manufacturing: Chip-free ceramics

14.02.2013
Rethinking the process used to machine industrially important ceramics could reduce damaging cracks and chips

Ceramics are hard, chemically inert and can withstand high temperatures. These attributes make them ideal structural components in engines, high-performance disk brakes and medical implants.

However, as ceramics are also brittle, using conventional tools — such as drills — to machine them is difficult. Instead, manufacturers rely on ultrasonic machining, in which a ‘hammer’ rapidly vibrates up and down. This process pushes slurry, which contains fine and abrasive grit, into the material and causes chipping.

Research by G.C. Lim and co-workers at the A*STAR Institute of Manufacturing Technology, Singapore, has now improved understanding of how this abrading process creates cracks in a ceramic, making it less durable for applications1. The team’s findings could inspire new approaches to machining ceramics, a key element in Singapore’s rapidly growing manufacturing sector.

Ultrasonic machining is known to leave cracks at the entrance and exit of a drilled hole, and a rough surface within the hole. Often, these defects are visible only under a microscope; nonetheless, they make the hole and surrounding material more susceptible to wear and tear. “Imperfections act as initiating locations, where cracks and fractures occur and propagate more easily than other places, resulting in early failure of the component,” says Lim.

The researchers studied crack formation by drilling holes of between 0.7 and 3.0 millimeters in diameter into plates made of 3 industrially important ceramics: silicon carbide, zirconia and alumina. They recorded images of the cracks and chips along the inner sides of the holes with a microscope and then used diagrams to model the way force is transferred from the hammering tool to the grit, and from the grit into the ceramic.

Lim and his colleagues found that as the grit removes material — by making tiny pits or rubbing against the walls — it creates cracks, which can be up to four times longer than the grit particles and extend out radially from the hole. The team concluded that these cracks are inherent to the way ultrasonic machining works, which means the number of cracks can be reduced by using smaller grit particles but never entirely eliminated.

Lim says they are now in a better position to optimize the drilling process. Since the smallest grit particles yield the smoothest holes but make drilling take longer, Lim recommends a two-step process: quickly drill a slightly smaller hole than needed with a large grit size, and then use a smaller grit size to make the final hole with a smooth finish.

The A*STAR affiliated researchers contributing to this research are from the Singapore Institute of Manufacturing Technology

Associated links
http://www.research.a-star.edu.sg/research/6629
Journal information
Nath, C., Lim, G. C., & Zheng, H. Y. Influence of the material removal mechanisms on hole integrity in ultrasonic machining of structural ceramics. Ultrasonics 52, 605–613 (2012).

A*STAR Research | Research asia research news
Further information:
http://www.research.a-star.edu.sg/research/6629
http://www.researchsea.com

More articles from Materials Sciences:

nachricht Nanomaterial makes laser light more applicable
28.03.2017 | Christian-Albrechts-Universität zu Kiel

nachricht New value added to the ICSD (Inorganic Crystal Structure Database)
27.03.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>