Featured Research

from universities, journals, and other organizations

Manufacturing: Chip-free ceramics

Date:
February 13, 2013
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
Rethinking the process used to machine industrially important ceramics could reduce damaging cracks and chips.

Rethinking the process used to machine industrially important ceramics could reduce damaging cracks and chip.

Related Articles


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 (see image). 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


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Chandra Nath, G.C. Lim, H.Y. Zheng. Influence of the material removal mechanisms on hole integrity in ultrasonic machining of structural ceramics. Ultrasonics, 2012; 52 (5): 605 DOI: 10.1016/j.ultras.2011.12.007

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Manufacturing: Chip-free ceramics." ScienceDaily. ScienceDaily, 13 February 2013. <www.sciencedaily.com/releases/2013/02/130213173041.htm>.
The Agency for Science, Technology and Research (A*STAR). (2013, February 13). Manufacturing: Chip-free ceramics. ScienceDaily. Retrieved March 29, 2015 from www.sciencedaily.com/releases/2013/02/130213173041.htm
The Agency for Science, Technology and Research (A*STAR). "Manufacturing: Chip-free ceramics." ScienceDaily. www.sciencedaily.com/releases/2013/02/130213173041.htm (accessed March 29, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Sunday, March 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Inspectors Found Faulty Work Before NYC Blast

Inspectors Found Faulty Work Before NYC Blast

AP (Mar. 27, 2015) An hour before an apparent gas explosion sent flames soaring and debris flying at a Manhattan apartment building, injuring 19 people, utility company inspectors decided the work being done there was faulty. (March 27) Video provided by AP
Powered by NewsLook.com
Facebook Building Plane-Sized Drones For Global Internet

Facebook Building Plane-Sized Drones For Global Internet

Newsy (Mar. 27, 2015) Facebook on Thursday revealed more details about its Internet-connected drone project. The drone is bigger than a 737, but lighter than a car. Video provided by Newsy
Powered by NewsLook.com
Robot Returns from International Space Station and Sets Two Guinness World Records

Robot Returns from International Space Station and Sets Two Guinness World Records

Reuters - Light News Video Online (Mar. 27, 2015) The companion robot "Kirobo" returns to earth from the International Space Station and sets two Guinness World Records. Sharon Reich reports. Video provided by Reuters
Powered by NewsLook.com
Residents Witness Building Explosion, Collapse

Residents Witness Building Explosion, Collapse

AP (Mar. 26, 2015) Witnesses recount the sites and sounds of a massive explosion and subsequent building collapse in the heart of Manhattan&apos;s trendy East Village on Thursday. (March 26) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins