20 US Patents Issued Related to Rapid Prototyping from 4/17/01 to 6/5/01

From: EdGrenda@aol.com
Date: Wed Jun 13 2001 - 05:32:32 EEST

Good Morning:

The latest edition of the RP Patent Alert Newsletter is now available on our
web site. Twenty RP patents were issued during the last month and a half.
Here are a few highlights of patents issued from 4/17/01 to 6/5/01:

* Stanford University has been granted a patent for its Shape Deposition
Manufacturing (SDM) process. Details are disclosed for this intermediate
scale method which combines features of silicon-based MEMS with rapid

* Huels Aktiengesellschaft of Germany has disclosed a rapid prototyping
method similar to selective laser sintering which utilizes microwave
radiation as the powder bonding means. A number of plastic materials are
said to be appropriate media and the authors claim the greater depth of
penetration of microwaves is an advantage compared to a laser source.

* The Korea Institute of Advanced Science and Technology has also invented a
variation on selective laser sintering which uses a wide area laser to heat
the powder surface to nearly its melting temperature, but uses an inkjet-like
head to do the actual selective bonding using superheated melted build
material. The method is said to minimize heat distortion and result in
greater accuracy.

* A couple of potentially important improvements to fused deposition modeling
have been patented by Stratasys. A water soluble material to provide support
structures for high pressure FDM has been disclosed. The material may
presage the use of stronger and tougher materials such as PEEK, PMMA,
polycarbonates and others with the method. The support material disclosed is
an amorphous polymer which exhibits low shrinkage upon cooling. The company
has also invented a means to valve the flow of the extruded plastic filament
used in the process by controlling the hardening of the plastic itself.
Mechanical configurations are described that are appropriate for fabricating
a controllable, widely variable gate. This could result in being able to use
a small amount of material to fabricate precise object details and larger
amounts to speed the process by filling large areas quickly.

* Inverse Tomographic Construction is being investigated by the University of
Utah. The method has been used to solidify a bead of photopolymer lying in
the center of a vat without recourse to a moving support platform as all
existing stereolithography methods require. The process works by applying
multiple exposures at various angles through the volume of the vat resulting
in kicking a special photopolymer above a hardening threshold.

* Five patents have been granted for dental technology related to or aided by
rapid prototyping. Align Technology has received three of these, further
fattening its portfolio for the InvisAlign (TM) process. Align recently
placed one of the largest orders ever made for stereolithography equipment
with 3D Systems.

* Ethicon has received a patent for an absorbable polyoxaester-based material
which can be used in a variety of medical applications. The main benefit of
the new material compared to previously available polymers is that it
transmits water vapor. It can be configured as a photopolymer to create
scaffolds for tissue engineering applications by means of stereolithography
and related processes.

* 3D Systems has invented a method of creating conformal cooling channels and
other thermal features in composite tooling. The technique should be
applicable to KelTool (TM), aluminum epoxy and other rapid tooling related

* Fully-dense ceramic parts can be created using an invention of the National
Science Council of Taiwan. Basically, the method is similar to selective
laser sintering and uses a somewhat higher power laser and a special
inorganic binder as means to fuse and bond thin layers of ceramic without
cracking or distortion.

There were numerous additional developments in closed loop stereolithography
control, liquid metal jet printing, manufacturing methods for ceramic and
other types of parts, etc. If you're involved with the development of RP
technology in industry or academia, you should find this an easy and
enjoyable way to keep up to date. Our main patent database includes more
than 700 rapid prototyping patents.

>From our home page,

The Worldwide Guide to Rapid Prototyping located at:


click the PATENTS button or use the direct link on that page.

Ed Grenda
Castle Island Co.
19 Pondview Road
Arlington, MA 02474 USA
781-646-6280 (voice or fax)
EdGrenda@aol.com (email)

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