4.3 Work Instructions & e-Records

Paper work instructions are a liability. They are static, easily defaced, and impossible to revoke instantly when a critical engineering change occurs. In a digital-first facility, the Work Instruction (WI) is not just a reference document; it is a context-aware control layer that dictates execution and captures the legal record of production.

Context-Aware Digital Work Instructions (DWI)

Do not treat the MES terminal as a PDF reader. The operator should never "search" for instructions. The system must push the exact page relevant to the specific unit and station.

The "Right Info, Right Time" Logic

• If Unit scans at Station 10 → Display WI-10 (Assembly).
• If Unit scans at Station 20 → Display WI-20 (Inspection).
• If Unit is a "Variant B" model → Highlight unique steps (e.g., "Add extra gasket") in Red.

Visual Standard

• Format: HTML5 / Interactive. Avoid static PDFs where possible.
• Media: Use short, looped GIFs for complex motions. A 5-second video is worth 1,000 words of text.
• Ergonomics: Text size must be readable from 1 meter away (Touchscreen distance).

Revision Control & Instant Supersession

The greatest risk in manufacturing is building today's product with yesterday's specifications. The digital link guarantees that the floor executes the current released engineering intent.

The Push Mechanism

When Engineering releases Rev B:

1. Immediate Kill: Rev A is marked "Obsolete" in the database.
2. Active Wipe: Any screen currently displaying Rev A forces a refresh.
3. Active Lock: The system pauses the line and displays a "New Revision Alert." The operator must acknowledge the change before resuming.

Pro-Tip: Use "Effectivity Dates" or "Serial Number Cut-ins." If a change applies only after SN 1000, the system must keep showing Rev A for SN 999, even if Rev B is released. This manages WIP transition automatically.

Electronic Records & Sign-Offs (e-Records)

An e-Record is the legal equivalent of a wet-ink signature. It transforms a "click" into a binding statement of fact.

Compliance Standard (21 CFR Part 11 Style)

Even if not regulated by the FDA, adopt these principles for robust liability protection.

• Attribution: The record must link undeniably to a unique User ID.
• Intent: The system must display what is being signed (e.g., "I certify this unit passed Visual Inspection").
• Authentication: Critical actions require "Double Auth" (Password or Biometric re-entry).

Sign-Off Levels

• Level 1 (Passive): Scanned badge to log in. Tracks "Who was at the station."
• Level 2 (Active): Button press "Job Complete." Tracks "Who did the work."
• Level 3 (Certified): Password re-entry for critical decisions (e.g., Releasing a quarantined lot).

The Audit Trail

The Audit Trail is the "Black Box" of the factory. It answers the "Who, What, When, Why" for every data point.

Immutability Rule

• If a record is created → It can never be deleted.
• If a record is wrong (e.g., Operator entered 500 instead of 50) → Create a new "Correction Record". The original 500 remains visible in history, crossed out but legible.

Traceability Query Logic

You must be able to reconstruct the history of a unit instantly.

• Query: "Show me all actions on Unit SN-12345."
• Result:
  1. 10:00 AM - Created (System)
  2. 10:05 AM - Assy Start (User: J.Doe)
  3. 10:15 AM - Torque Recorded: 5.0Nm (Tool: TQ-01)
  4. 10:20 AM - Inspection Fail (User: Supervisor)
  5. 10:30 AM - Rework Complete (User: RepairTech)

Final Checklist

Category	Metric / Control	Threshold / Rule
Delivery	Context	WI auto-loads based on Station + Product ID
Revision	Latency	New Revisions live instantly (< 1 min)
Versioning	Safety	"Obsolete" docs legally inaccessible to Operators
Sign-Off	Authentication	Critical Ops require Re-Authentication (Pwd/Bio)
Audit	Retention	Logs kept for Product Lifetime + X Years
Integrity	Correction	No Deletes. Only "Strikethrough + New Entry"
Visuals	Clarity	Key variances highlighted for mixed-model lines