LMD Quality Evidence Ladder
What monitoring can show, and what inspection must prove.
AI and process monitoring can make LMD workflows more observable, but observation is not certification. I use this ladder to separate evidence levels so RFQs, monitoring plans, and release decisions use the right proof for the right risk.
Visual ladder
Nine evidence levels for LMD quality claims
- 1
Visual process observation
What it shows: Gross process behavior, obvious interruptions, accessibility, and operator-visible instability.
What it does not show: Internal defects, mechanical properties, subtle metallurgical issues, and repeatability.
How AI can help: Can summarize observations and flag visible anomalies when video is available.
When stronger evidence is needed: Needed when the part has dimensional, structural, or safety requirements.
- 2
Machine log and parameter record
What it shows: Nominal power, feed rate, travel speed, shielding, and process history.
What it does not show: Whether the actual melt pool and deposit quality matched the planned parameters.
How AI can help: Can detect parameter drift, unusual sequences, and incomplete records.
When stronger evidence is needed: Needed when parameters alone cannot prove material state or geometry.
- 3
Melt-pool image or process video
What it shows: Thermal/process signal behavior, local instability, spatter, and relative process trends.
What it does not show: Final mechanical properties, internal soundness, and service performance.
How AI can help: Can classify anomalies and correlate visible signals with risk.
When stronger evidence is needed: Needed for any quality claim beyond process awareness.
- 4
AI anomaly detection
What it shows: Patterns that differ from training examples or expected process behavior.
What it does not show: Root cause, acceptability, and final part conformance.
How AI can help: Provides a risk indicator and prioritizes inspection attention.
When stronger evidence is needed: Needed when release decisions, safety, or acceptance criteria are involved.
- 5
Dimensional inspection
What it shows: Geometry, tolerance, machining allowance, and final fit-related evidence.
What it does not show: Internal defects and metallurgical properties.
How AI can help: Can compare scans, highlight deviations, and connect geometry drift to process history.
When stronger evidence is needed: Needed when internal integrity or material properties matter.
- 6
NDT: CT, UT, PT, MT
What it shows: Evidence about cracks, porosity, lack of fusion, surface-breaking or internal discontinuities depending on method.
What it does not show: Full mechanical performance and some microstructural or service-condition behavior.
How AI can help: Can support indication triage and traceability, subject to validated inspection workflows.
When stronger evidence is needed: Needed when acceptance requires destructive or property-based evidence.
- 7
Metallography and hardness testing
What it shows: Microstructure, heat-affected zone, dilution, hardness, and local material condition.
What it does not show: Full component-level service performance.
How AI can help: Can link process signatures to measured physical outcomes over time.
When stronger evidence is needed: Needed for critical load cases or qualification.
- 8
Mechanical or functional testing
What it shows: Strength, fatigue, wear, pressure, fit, or functional performance under defined tests.
What it does not show: Long-term field behavior outside the tested conditions.
How AI can help: Can learn from validated outcomes and improve future risk scoring.
When stronger evidence is needed: Needed when real operating exposure is the decisive proof.
- 9
Field performance
What it shows: Real service behavior, durability, and failure modes under operating conditions.
What it does not show: Controlled isolation of every cause without supporting records.
How AI can help: Can connect in-service outcomes back to process, inspection, and repair-route data.
When stronger evidence is needed: This is the strongest evidence tier, but it still depends on traceable context.
CTA
Use this ladder when designing LMD monitoring workflows or RFQ evidence requirements.
Disclaimer
Preliminary decision-support only. Final feasibility depends on base material, geometry, service conditions, inspection requirements, and expert review.
Framework path