I saw this in Opto & Laser Europe , Issue 60, March 1999, and thought that
it might be of interest to some of you.
Regards,
Allan.
Laser Sintering of Ceramics Extends Rapid Prototyping.
Ceramic powders have joined bronze alloys to sinter components.
Laser sintering is a method of rapid prototyping that builds up parts in
layers. Until now only a bronze alloy has commonly been used for sintering.
The Fraunhofer Institute for Material and Beam Technology (IWS), in
conjunction with the Fraunhofer Institute for Ceramic Technologies and
Sintered Materials, both in Dresden, Germany, has developed a process in
which structural ceramics can be sintered without organic binding agents.
The researchers infiltrate silicon into silicon carbide to form SiSiC.
"The density, and the mechanical and thermal properties of silicon carbide
can be controlled well by means of silicon infiltration," said Wolfgang
Loschau of IWS.
First, pure silicon carbide powder is built up in layers 50um thick in a
metal sintering plant and irradiated in an oxidising atmosphere with a
100W CO2 laser to produce a matrix. In the second stage the relatively
porous matrix is infiltrated with silicon in a vacuum oven at 1600 deg. C.
"The components produced in this way are almost perfectly net-shaped,"
said Loschau. "They can be machined without difficulty and they possess
high rigidity and heat conductivity."
IWS has already produced several mock-ups and prototypes - laser
reflectors eight times as light as conventional metallic mirrors, for
example.
"In addition, the selective laser sintering of structural ceramics can
be used for producing optical components for spacecraft, parts for car
engines or aero engines, and the individual parts of tools," Loschau
added.
Contact Wolfgang Loschau,
e-mail "loeschau@iws.fhg.de",
fax +49 351 2583 300.
--Allan E W Rennie Research Student Centre for Rapid Design and Manufacture Buckinghamshire Chilterns University College Queen Alexandra Road High Wycombe Bucks, HP11 2JZ UK
Tel: +44 (0)1494 605085 Fax: +44 (0)1494 538593
http://www.buckscol.ac.uk/tech/crdm/crdm.html
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