3.5 Work Instructions & e-Records

Paper work instructions are a liability. They are static, easily defaced, and impossible to revoke instantly. If an Engineering Change Order (ECO) is released at 09:00, a paper-based factory is still building the "Old Way" at 10:00. The goal of Electronic Work Instructions (EWI) is not to "digitize the binder," but to synchronize the operator's visual field with the active BOM, Revision, and User Capability.

Station Control & Skill Enforcement

Before showing a single instruction, the system must validate the human at the screen. Access is a privilege, not a default state.

1. The Login Logic

Do not use generic "Line 1" accounts. Every mouse click must trace to a legal identity.

• Mechanism: RFID Badge Scan or Biometric. (Typing passwords is too slow for the floor).
• Timeout: Implement "Auto-Logout" on inactivity (e.g., 15 mins) to prevent "Ghost Records" where Operator B works under Operator A's login.

2. The Skill Matrix Gate (Certification Check)

Just because you can log in doesn't mean you can build.

• Logic: If Work_Order requires "Soldering Class 3" AND User_Skill ≠ "Soldering Class 3" → Then Block Station. Display: "Certification Missing."
• Expiry: If Certification_Date < Today → Then Block Station.
• Override: Requires Supervisor Badge scan to authorize a "Trainee Mode" (where the Supervisor accepts liability).

3. Shift Handover

Production is continuous; shifts are not.

• The "Hot Swap": Allow Operator B to scan in while Operator A is still logged in.
• Action: System closes Operator A’s session (End Timestamp) and starts Operator B’s session (Start Timestamp) instantly. No downtime.

The Architecture of EWI

Do not simply display a PDF on a monitor. A PDF is passive. An EWI system must be Context-Aware and Interactive.

Context-Aware Display

The MES knows the Work Order, the Unit ID, and the Routing Step. The screen must filter the content accordingly.

• Logic: If Unit = Variant A → Then Show Assembly Image A. Hide Image B.
• Logic: If Operator = Trainee → Then Enforce "Step-by-Step" confirmation (Click 'Next' 10 times). If Expert → Allow "Batch" confirmation (Click 'Done' once).

The "Read and Understood" Gate

Operators often ignore updates because they look like the old instructions. You must force acknowledgment of change.

• Mechanism: Track the Last_Acknowledged_Rev for every User-Product pair.
• Logic:
  • If Current_Rev > User_Last_Ack_Rev → Then Lock Screen.
  • Action: Display "Change Summary" (Diff). Require Digital Signature to proceed.
  • Result: The excuse "I didn't know it changed" is technically impossible.

Electronic Records (e-Records)

The EWI is the Input; the e-Record is the Output. Every action taken by the operator must generate a permanent, immutable database row. This is your defense during an audit (FDA 21 CFR Part 11 / GMP).

Data Capture Types

1. Implicit Data (Passive):
   • Who: User ID.
   • When: Timestamp (UTC).
   • Duration: Time_End - Time_Start. (Detects if an operator blindly clicked "OK" in 1 second for a 5-minute task).
2. Explicit Data (Active):
   • Confirmation: "I have inspected the seal." (Checkbox).
   • Variable: "Torque Value = 4.5 Nm." (Keypad/Tool Input).
   • Evidence: "Photo of the cable routing." (Camera Input).

Validation Logic

Do not accept data blindly. Validate at the point of entry.

• Range Check: If Input < 4.0 or > 5.0 → Then Reject Entry. Display "Out of Spec".
• Format Check: If Input is Text but Field expects Float → Then Block Entry.
• Mandatory Fields: If Critical Field is Empty → Then Disable "Complete" button.

The "ALCOA+" Standard

Adhere to the ALCOA+ framework for data integrity. The MES architecture must guarantee these five attributes for every record.

1. Attributable: Linked to a unique User ID.
2. Legible: Stored in human-readable format (or easily rendered).
3. Contemporaneous: Recorded at the exact moment of execution.
4. Original: The first record is the master.
5. Accurate: Validated against limits (Min/Max) at the source.

Handling Corrections

Operators make mistakes. The system must allow correction without destroying history.

The Audit Trail Logic

• Scenario: Operator enters "50mm", saves, realizes it should be "5.0mm".
• Action: Operator updates value.
• Database Record:
  • Row 1: Value="50", Status="Obsolete", Timestamp=10:00, User=John.
  • Row 2: Value="5.0", Status="Active", Timestamp=10:01, User=John, Reason="Entry Error".
• Constraint: Never perform an SQL UPDATE or DELETE on a production record. Always INSERT a new version.

Final Checklist

Category	Metric / Control	Threshold / Rule
Access	Skill Gate	Block Login if User_Certification is missing or expired.
Identity	Attribution	100% of records linked to a specific User ID (No generic logins).
Versioning	Rev Match	EWI Revision must match the Work Order BOM Revision.
Training	Change Control	Force "Read & Sign" pop-up when Operator encounters a new Revision.
Integrity	Immutability	Zero DELETE permissions on Production History tables.
Inputs	Logic Gates	Block "Next Step" until all Mandatory Fields are populated.
Audit	Correction	Field edits require a "Reason Code" and preserve the old value.