Featured Research

from universities, journals, and other organizations

New Approach To Surface Profiling Will Help Automakers

Date:
January 15, 2008
Source:
National Institute of Standards and Technology
Summary:
Researchers have developed a novel technique for measuring the roughness of surfaces that is casting doubt on the accuracy of current procedures. Their results could cut development costs for automakers as they design manufacturing tools for new, fuel-efficient, lightweight alloys.

The four images (taken with scanning laser confocal microscopy) show variations in surface roughness of an aluminum alloy as produced by increasing amounts of strain: A-1 percent, B-4 percent, C-8 percent, and D-12 percent.
Credit: Mark Stoudt, Joseph Hubbard and Stanley Janet, NIST

Researchers at the National Institute of Standards and Technology (NIST) have developed a novel technique for measuring the roughness of surfaces that is casting doubt on the accuracy of current procedures. Their results announced in a forthcoming paper* could cut development costs for automakers as they design manufacturing tools for new, fuel-efficient, lightweight alloys.

Related Articles


Surface roughness is a key issue for auto manufacturers and other industries that use sheet metal, one that goes far beyond simple cosmetics. Faint striations and other marks that appear when metal is shaped can indicate residual stresses that can cause the part to fail later on. They also lead to extra wear and early retirement for the expensive stamping dies used to form sheet metal into fenders and other body parts (a typical production die can cost $2 million or more.)

And measures of surface roughness feed into models that predict friction and the metal's "springback"--the amount it will unbend after being stamped. Springback has to be known and controlled to build accurate dies for complex metal shapes. A significant cost in introducing new lightweight alloys for cars is the trial-and-error process needed to develop a new set of dies for each new alloy.

Conventionally, roughness is measured with a profilometer, an instrument with a probe like a high-tech phonograph needle that is tracked in a line across the test surface to record the peaks and valleys. The process is repeated several times at intervals across the test surface, and the results are averaged into a "roughness" figure. (New non-contact instruments use optical probes, but the idea is the same.) But NIST researchers have found that these measures may be misleading--as both measurement uncertainties and statistical errors are compounded when the 2-D lines are extrapolated to the entire surface.

NIST's approach uses data from a scanning laser confocal microscope (SLCM), an instrument that builds a point-by-point image of a surface in three dimensions. The data from a single SLCM image--representing an area of about 1000 X 800 micrometers by 20 micrometers in depth--are analyzed using mathematical techniques that treat every point in the image simultaneously to produce a roughness measure that effectively considers the entire 3-D surface rather than a collection of 2-D stripes.

One early finding is that the generally accepted linear relationship between surface roughness and material deformation is wrong, at least for the aluminum alloy the group studied. The more accurate data from the 3-D analysis shows that a more complicated relationship was masked by the large uncertainties of the linear profilometers. The NIST researchers hope their new technique will lead to more accurate models of the effects of strain on new alloys and, eventually, lower development and tooling costs for metalworking industries.

* M.R. Stoudt, J.B. Hubbard and S.A. Janet. "Using matrix methods to characterize evolution of deformation induced surface roughness in aluminium sheet," Materials Science and Technology, In Press.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology. Note: Materials may be edited for content and length.


Cite This Page:

National Institute of Standards and Technology. "New Approach To Surface Profiling Will Help Automakers." ScienceDaily. ScienceDaily, 15 January 2008. <www.sciencedaily.com/releases/2008/01/080109173756.htm>.
National Institute of Standards and Technology. (2008, January 15). New Approach To Surface Profiling Will Help Automakers. ScienceDaily. Retrieved February 28, 2015 from www.sciencedaily.com/releases/2008/01/080109173756.htm
National Institute of Standards and Technology. "New Approach To Surface Profiling Will Help Automakers." ScienceDaily. www.sciencedaily.com/releases/2008/01/080109173756.htm (accessed February 28, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Saturday, February 28, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Elon Musk's Hyperloop Moves Forward

Elon Musk's Hyperloop Moves Forward

Buzz60 (Feb. 27, 2015) Zipping around at 800-miles an hour is coming closer to reality in California. An entire town is being built around Elon Musk&apos;s Hyperloop concept and it wants you to stop in for a ride when it&apos;s ready. Brett Larson is on board. Video provided by Buzz60
Powered by NewsLook.com
Vibrating Bicycle Senses Traffic

Vibrating Bicycle Senses Traffic

Reuters - Innovations Video Online (Feb. 26, 2015) Dutch scientists have developed a smart bicycle that uses sensors, wireless technology and video to warn riders of traffic dangers. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
In Japan, Robot Dogs Are for Life -- And Death

In Japan, Robot Dogs Are for Life -- And Death

AFP (Feb. 25, 2015) Robot dogs are the perfect pet for some in Japan who go to repairmen-turned-vets when their pooch breaks down - while a full Buddhist funeral ceremony awaits those who don&apos;t make it. Duration: 02:40 Video provided by AFP
Powered by NewsLook.com
London Show Dissects History of Forensic Science

London Show Dissects History of Forensic Science

AFP (Feb. 25, 2015) Forensic science, which has fascinated generations with its unravelling of gruesome crime mysteries, is being put under the microscope in an exhibition of real criminal investigations in London. Duration: 00:53 Video provided by AFP
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