RE: LENS

From: Timothy J Gornet (tim.gornet@louisville.edu)
Date: Thu Mar 13 2003 - 19:34:43 EET


The processes are all similiar to laser cladding where you get a
metallurgical bond between materials as opposed to the mechanical bond
of a weld. On the POM DMD, cameras are used to provide feedback and
prevent getting a large heat affected zone as you would in welding. The
deposition is tightly controlled so you get a controlled quenching
effect where the grain structure is very tight with no directionality
like you might find in wrought alloys. The LENS people have published
numbers showing increased strength without loss of elongation for the
deposited material. You can't violate laws of metallurgy however with
these machines. You still have to worry about the solubility of
different materials within each other for compatibility when using
different materials.

Tim

Tim Gornet Computer Aided Engineering Consultant
INTERNET: tim.gornet@louisville.edu
SLUGNET: Vogt Bldg. Rm 101, University of Louisville, Louisville, KY
40292
PHONENET: (502)852-0714 FAXNET: (502)852-8890
Rapid Prototyping Center
http://www.louisville.edu/speed/rpc/

>>> Makai Smith <smith@vsba.com> 03/13/03 11:53AM >>>
I'll check out the links for specifics, but something accurs to me
about the
functional differentiation of materials within a model.

>How do you represent a part with multiple materials in
>different areas or gradient materials in a CAD solid model???
As an architect, I'm certainly no expert of this, but what about using
other
representations that the typical vector representations found in
geometric
modeling. I'm thinking of voxels or (maybe?) adaptive distance
fields.
Some type of representation where each "entity" doesn't have its own
completeness, where the material type can vary more or less
continuously,
like color in an image?

Seems like the software industry went with vector/CAD based
representations
at the beginning due to the efficiency of representation on early
hardware.
Now the computing power is available, I'm wondering when 3D modeling
will
find new paradigms.

-makai

-----Original Message-----
From: Timothy J Gornet [mailto:tim.gornet@louisville.edu]
Sent: Thursday, March 13, 2003 11:06 AM
To: rp-ml@rapid.lpt.fi; Makai Smith
Subject: Re: LENS

AeroMet has been a very successful application for creating Ti large
scale airframe type parts. Optomec has concentrated initially on Ti
due
to its focus on government funded research in that area. Equipment
from
Optomec is commercially available and in use. In addition, POM of
Detroit has a competing technology, direct metal deposition (DMD),
that
started with a focus on tooling and tooling modification using tool
steels, SS, etc.... Both DMD and LENS are based on a couple of patents
from Los Alamos and Sandia but had different goals at the start. Both
technologies seem to be progessing fairly rapidly with their
technologies. The areas of Ti parts, multi and gradient materials,
tool
modification, and high thermal conductivity assemblies are in use.
POM,
www.pomgroup.com , has an overview of their equipment and processes
online. They have been quite successful in Detroit with tooling
modification as well as other new applications. LENS info can be found
at www.optomec.com . Check out the M3D technology for direct write
electronics. Aeromet, www.aerometcorp.com , has an informative web
site
on their activities - they have received quite a bit of DOD type
funding
as well.

All three technologies are quite feasible today for many applications,
each with their own areas of focus.

Aluminum is a more difficult material to deposit for a couple of
reasons, reflectivity and low melt point. These technologies are best
for high performance materials that are difficult to machine or very
expensive to have the chips fly as waste (Ti). For example, if you
need
a hardened tool steel tool, think of being able to machine a preform
with 95% of all geometry out of cold roll steel which machines like
butter and add a H13 tool steel surface or other more exotic material
or
blend of material. POM deposits H13 with a hardness of about 53
Rockwell. The possibilities are endless: conformal cooling, embedded
sensors, high or very low thermal conductivity,etc...

The real issue with the advanced use of these machines has more to do
with solid modeling software limitations. They are basically reverse
NC
machining. How do you represent a part with multiple materials in
different areas or gradient materials in a CAD solid model??? Then
deposit that way?

We have a POM DMD 3000 machine and have been using it for over 6
months
on many applications. It is NOT rapid prototyping. It is more of a
machine tool. More work goes into setup than in the deposition. Set up
is similiar to NC machining so fixturing, tool access (or deposition
head in this case) needs to be considered. The rules of deposition are
different than those of removal. Stainless runs great in this
equipment.

Check out the applications on the different web sites.

Tim

Tim Gornet Computer Aided Engineering Consultant
INTERNET: tim.gornet@louisville.edu
SLUGNET: Vogt Bldg. Rm 101, University of Louisville, Louisville, KY
40292
PHONENET: (502)852-0714 FAXNET: (502)852-8890
Rapid Prototyping Center
http://www.louisville.edu/speed/rpc/

>>> Makai Smith <smith@vsba.com> 03/13/03 09:45AM >>>
List:

Would anyone mind saying a few things about Laser Engineered Net
Shaping?

What about the progress of AeroMet's application of Sandia research?

Where is this technology at, say with regard to commercial feasibility
and
cost? Timeframe?

Why has development focused on the sintering of Ti? Would it be
possible to
use a process for fabricating in stainless or aluminum?

|\/| /\ |< /\ |
_________________________________________
O. Makai Smith smith@vsba.com



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