Gentlemen:
Indeed you are correct in your assumption that this will become a bigger issue as time
goes on, and it's very useful for society to think about this now - before explosive
growth in the field buries us in waste from additive processes. Fortunately, I believe
there's sufficient time to do this, and probably a lot of desire within the industry to
make sure ahead of time they're not caught in this potentially costly trap.
The only people I know of who've provided an extensive tabulation of RP materials in
the past are CADCAM Publishing which was subsumed in the last year or so into:
Cyon Research Corporation
8220 Stone Trail Dr.
Bethesda, MD 20817-4556
301.365.9085
301.365.4586 FX
info@cyonresearch.com
Dr. Joel Orr, Chief Visionary
I don't know whether they've carried this on or not after the merger/purchase. I doubt
it because there's little economic incentive to do so.
I would suggest you look at our site under the RP brief Tutorial, FAQs and bibliography
sections to get some idea of what today's materials are like for various processes. The
future will look much like the present, but there will be a much greater variety of
plastics and photopolymers used. Processes that use basic engineering materials such as
plastics, for example FDM and SLS, have exactly the same recycling issues as would the
larger community using these materials.
Photopolymers.used in stereolithography and jetted systems, may have other issues,
especially regarding the disposal of reactive, uncured resins. Theoretically, at least,
once cured they should be very similar to the base polymers that are formed - typically
these days acrylics or epoxies. The types of these base materials can be expected to
expand, however.
The best - and possibly only understandable - sources of information on the fine
aspects of photopolymers would be the companies manufacturing them and the few researchers
in universities working under contract to these companies. You can find all those
companies using directory resources on our site, and most of the researchers by using our
bibliography.
Of course, the other great source of in-depth info is the patent system. However,
deciphering that material is very difficult because much of it is presented in an
intentionally obscure fashion, particularly for photopolymers.
The many other RP processes - and some of the above - also use things like paper,
ceramics and metals of many kinds, etc. Three dimensional printing has its own cast of
characters including starches, plaster and soon plastics. You can eat the starch (but
don't), and I don't think there's much out of the ordinary that has to be done with
plaster or the plastics. However, these materials are often infiltrated with adhesives to
strengthen them. That's another amusement that deserves consideration.
To the extent that plastics and metals are recyclable, I believe the answer is "yes,"
most materials are recyclable today. Photopolymers - that needs to be looked at more
closely. One interesting place to start is this patent:
6660208 Detoxification of solid freeform fabrication materials
Hanna; Stephen D. (Los Angeles, CA)
3D Systems, Inc. (Valencia, CA)
Some of the issues are the same as in detoxification. This patent and related work are
aimed at making sure photopolymers are safe for applications like hearing aids.
One of the areas that's under strong development in the field of rapid manufacturing is
composites - many types of materials put together in a myriad of ways. Find out a lot more
in our section on the subject of rapid manufacturing. That's certainly where a lot of work
is heading - and it represents a major recycling headache. It's tough enough to recycle
with materials that are clearly labeled and generally of uniform composition. What happens
when you intimately mix things using a complex gradient? Or you mix disparate materials
like metals and ceramics? Little fun will be involved in trying to get these things apart.
It may not be possible and wholly new approaches required. One good questions is what do
people do with composite materials today? Are they recycled? I have no idea.
These (and what I've described above) are the general trends for the next 5 to 10
years. In 50 years, I'll have the advantage of being dead and not having to worry about it
- but I think a good guess is that materials technologies will merge with computation,
electronics and other advanced technologies to yield whatever is the thing after smart
materials. You can get a glimmer of it in some of the work being done at MIT to develop
futuristic soldier suits, and the mesoscopic devices for airplane skins being worked on at
Stanford.
Maybe in 50 years recycling is moot: Your additively fabricated composite sport coat
need not be recycled because software downloaded from passing satellites by the coat not
only monitors your every bodily function, but updates and incrementally reconstructs the
color and cut of the jacket to reflect the latest style, alters its size to fit your
burgeoning body, and repairs tears and rips using clotting-like processes. Required
materials are absorbed from the air which has been seeded universally with gas molecules
that form the raw materials for nearly all industrial and consumer processes, but are
completely harmless and actually contain vitamins and smell nice. Active heating and
cooling keep you comfortable in all seasons, and foreign substances are fought off using
techniques like white blood cells fight antigens. This keeps the coat clean but larger
spots and accidents are automatically removed by localized mechanical exchange of water
vapor from the air. Detergents are synthesized in the process which are specific to the particular insult; samples of the detergent programming are
sequestered locally for future use by the jacket because it now knows exactly what kind of
slob you are, and what area you spill on it. The coat costs 1,000 Universal Credits which
is the equivalent in today's money of just three cents.
As wacko as that sounds, it probably doesn't go far enough.
You've attacked a big problem and you might want to limit your work to either defining
the future issues, or seeing what's what in detail with a specific class of materials. I'd
be very interested in receiving your final report.
I hope this helps and I send best regards.
Ed Grenda
Castle Island Co.
The Worldwide Guide to Rapid Prototyping
