Replies to post #70174 on Sigma Labs Inc (SASI)

[El_Jefe42]

I don't recall seeing much about the idea that in-situ has a perceived reliability issue. This presentation seems to support its future use, but would be nice for SGLB to defend PR3D against this argument.

From page 12 of the NASA presentation ...

In situ Process Monitoring

How to approach in-situ monitoring of AM processes?
• Harnessing the technology is only half the battle
• Detectors, data stream, data storage, computations
• Second half of the battle is quantifying in-situ process monitoring reliability

Community must realize that passive in-situ monitoring is an NDE technique
1. Understand physical basis for measured phenomena
2. Proven causal correlation from measured phenomena to a well-defined defect state
3. Proven level of reliability for detection of the defective process state
False negatives and false positives ? understanding and balance is needed

Closed loop in-situ monitoring adds significantly to the reliability challenge
No longer a NDE technique – may not be non-destructive
Establishing the reliability of the algorithm used to interact and intervene in the AM process
adds considerable complexity over passive systems

Thx ss. Here is a recent nasa pres w a focus on in-situ monitoring as well. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20190030383.pdf
glta