Sigma Labs, Inc. (NASDAQ:SGLB), a provider of quality assurance software under the PrintRite3D brand, announced the June 30, 2016 publication of its U.S. Patent Application No. US 2016/0185048; Multi-Sensor Quality Inference and Control For Additive Manufacturing Processes.

This patent application is related to real-time quality analysis during additive manufacturing (AM) processes and the characterization of material properties using acoustic signals emitted during AM which can be used in addition to optical signals to simplify the qualification of printed parts.

It also encompasses a multi-sensor quality inference system for additive manufacturing that is capable of discerning and addressing three quality issues:

–process anomalies, or extreme unpredictable process events uncorrelated to process inputs

–process variations, or difference between desired process parameters and actual operating conditions

–material structure and properties, or the quality of the resultant material created by the AM process. It further embodies the use of the gathered sensor data to evaluate and control additive manufacturing operations in real time.

The application, which has a priority date of November 18, 2014, describes how optical sensors can be used to measure oscillations (e.g., greater than 1,000 Hz) in the melt pool and that these readings could be augmented by artificially illuminating the melt pool with a laser to help collect specular reflections that include oscillation frequency information. This application also describes how an acoustic sensor can be used to acoustically monitor a build process by listening for micro-cracking occurring as a workpiece is built and may be used to eliminate post-build quality control processes such as CT scanning which adds an extra process to production and can be quite time intensive.

The use of acoustic characterization during AM operations may be becoming a widespread technique in the AM industry. GE has filed patent applications related to acoustic monitoring methods (US 2017/0146488 and US 2017/0146489).  The GE applications were filed with the Patent Office one day after Sigma Labs’ application.

Sigma Labs, Inc.
www.sigmalabsinc.com