Hi Peter,
See this thread -
http://www.iceinspace.com.au/forum/s...ad.php?t=78056
These have been around for many years and are quite common in industry now, particularly for rapid prototyping and we use them ourselves.
In recent years, companies such as 3D Systems Inc. (NASDAQ DDD) have started to bring out commercial "personal 3D printers"
in the sub $10K range, such as their V-Flash. See
http://printin3d.com/3d-printers/v-f...nal-3d-printer