RE: Solar in RP's future?

From: Manfred Hofmann (
Date: Mon Jan 31 2000 - 09:15:27 EET

New ideas are always welcome!

I think the concept of using the natural energy source is quite tempting (it would be even more so for UV lasers where the kW-hour runs more in the $ 10000 range). As you mention, the focus of concentrated sunlight would not be as tight as for a laser (and you would have to correct for fluctuating intensity and solar position) but where it would really pay off is in large prototypes (boat hulls, construction etc).
If you count on about 1 kW per square meter, don't forget to add a broadband absorber to the sinter material.
Take an old CNC mill or laser cutter and show a proof-of principal.


Manfred Hofmann Phone: +41 26 439-9595
Rapid Prototyping Chemicals Fax: +41 26 439-9599
P.O. Box 259
CH-1723 Marly, Switzerland e-mail

-----Original Message-----
From: Jim Mallos []
Sent: Saturday, January 29, 2000 1:44 PM
Subject: Solar in RP's future?

The light from an industrial laser ends up costing on the order of $10 per kilowatt-hour.
By comparison, the plain old thermal energy we now use to make products costs a penny per kilowatt-hour. This thousand-to-one disadvantage in energy costs makes it unlikely that lasers will directly form any but the highest-value products.
Happily for us there is another source of intense optical radiation which costs only 1 to 10 cents per kilowatt-hour---the solar furnace.
While prototyping cannot wait for the sun to come out, delivery times of a few days prove acceptable for most products. The flux a solar furnace can generate is only about 10% that being used today in selective laser sinterers. The consequences for selective solar sintering: slower part production, and coarser resolution in any given material. Nonetheless, I believe the range of potential products is vast.
Not much mirror area will be needed, as every square meter of direct sunlight has the same radiant power as a 1 kw laser.
I am starting a "Making Things from Sunlight" web page at ." It is aimed mainly at students and "homebrew" investigators interested in developing this new technology. Right now the page it is just a slim list of links. Any pointers to additional information would be greatly appreciated.

Jim Mallos
Heliakon Solar Sintering Lab

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