Technology
SENTINEL is a firmware-level screening layer for FDM and resin printers. It evaluates every print file against firearm-blueprint signatures on the printer's own hardware — no cloud, no uploads, no telemetry on your customers' designs.
The pipeline
SENTINEL hooks the printer's job queue below the interface layer, so every input path — USB, SD card, LAN, cloud slicer, mobile app — funnels through the same checkpoint. A print cannot start until a verdict exists, and bypassing the layer is treated as a tamper event.
The mesh is normalized — scale, orientation, tessellation — and reduced to a rotation-invariant geometric fingerprint. Renaming a file, rescaling a part, or splitting a receiver into innocuous-looking segments doesn't change what the geometry is.
Fingerprints are scored against a curated corpus of firearm frames, receivers, and regulated components. Assembly-context heuristics catch multi-part evasion, where each piece looks harmless and the set does not.
Cleared jobs release instantly. Blocks are enforced at the motion-planner boundary and recorded in a tamper-evident local log, giving manufacturers the audit trail regulators will expect at attestation time.
Design principles
A blocking layer has two customers with opposite fears: regulators worried it misses too much, and makers worried it blocks too much. SENTINEL's architecture answers both.
For regulators
False-negative rate — a firearm that slips through — and resistance to circumvention are the heart of the DOJ's forthcoming performance standards. Our evaluation harness treats those as first-class release gates, not afterthoughts.
For makers
A compliance layer that blocks a phone stand is dead on arrival. Ambiguous geometry gets a deeper second pass on-device rather than a lazy block, keeping legitimate prints flowing.
Under the hood
Spec sheet
What SENTINEL is not
Not a cloud filter — screening is local. Not a design censor — the signature corpus targets firearm frames, receivers, and regulated components as the statute defines them. Not a data harvester — there is nothing to harvest; files stay on the printer.
No cloud dependency Privacy-preservingIntegration docs, evaluation methodology, and certification roadmap — available to manufacturer partners under NDA.
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