OEE & Andon Dashboard

Problem

Large shop floor (40 CNC machines); operators couldn't see overall KPI. Supervisors wanted physical alerts (3-color tower) when any machine's OEE dipped — not only a dashboard.

Architecture

Existing MES → webhook trigger → Three.js WebGL renderer on a 4K smart TV (Android TV → Chromium kiosk) → Modbus TCP 16-channel relay → 3-color Andon tower (green/yellow/red). Every light change is logged in Postgres for audit.

Stack & rationale

• Three.js / WebGL: 60fps 4K dashboard with no lag; CSS layouts drop frames.
• Modbus TCP relay over serial: Wi-Fi/Ethernet, less floor wiring.
• Chromium kiosk on Android TV: cheap ($150 vs $1000 PC), good uptime.

Results

• 40 CNC machines monitored together at 1 Hz refresh, smooth
• Andon tower responds <1 s after trigger
• Supervisors react to downtime ~6 min earlier on average
• Cost per node: $180 (TV + Pi 4 + relay)

Lessons

WebGL chews RAM rendering text → use instanced text quads, not TextGeometry. Andon tones matter: blinking yellow for warning, steady red for critical.

Security & Compliance

• OT/IT network segmentation: PLCs only talk to the MES bridge, never exposed to the Internet.
• Read-only PLC by default: only privileged commands can write tags; log + 4-eyes confirm for production-critical changes.
• Signed OTA for Andon panel firmware.
• Full audit trail for ISO 9001 + FDA-style batch traceability.