Sigma Labs Inc (SASI)

[alanthill]

The following is from an article in "Industrial Lasers" on the status of in-process monitoring development in Additive Manufacturing. It would seem to cast some doubt as to whether GE will initiate the production of the fuel nozzles with SGLB's products or anyone elses for that matter.

In late 2011, Prabhjot Singh, manager of GE's Additive Manufacturing Lab, observed: "[An AM] part is made out of thousands of layers, and each layer is a potential failure mode. We still don't understand why a part comes out slightly differently on one machine than it does on another, or even on the same machine on a different day." [9]
In large part, that assessment is still accurate today. In the meantime, early adopters like GE Aviation have spent years learning the nuances of their AM tools, characterizing the process windows and sensitivities, creating process databases, and qualifying each machine. The early adopters will likely begin their production ramps in the next 12–18 months without process monitoring or closed-loop laser power control on their production equipment, relying instead on their deep knowledge base to keep the machines producing good parts.
The sensors and sensed quantities being pursued today for AM process monitoring are mostly derived from experience with established processes such as laser welding. As such, they may or may not turn out to be the best means of identifying AM process anomalies in situ. It is still the early days for metal AM, and the equipment and powder materials are evolving rapidly. So, too, will sensing and data analysis technologies. Parallel efforts are currently underway to carry out physics-based simulations of the laser-powder bed interactions, and to establish detailed databases tying material properties to process parameters and powder characteristics. In the next several years, these may help illuminate the optimal quantities to monitor, point by point, in or near the melt pool, as well as the best sensors to use. Meanwhile, rapid innovation will continue, though the advent of truly robust process monitoring and control is probably still a few years away. As major manufacturers plan for volume production of metal AM parts, we should expect to see more emphasis being placed in this area and much continued development activity. The AM process monitoring race is on, and the winning technologies and competitors have yet to be identified, much less declared.

Read the entire article here:
http://www.industrial-lasers.com/articles/print/volume-29/issue-5/features/process-monitoring-in-laser-additive-manufacturing.html