6.9 Picking, kitting & line release discipline

Kitting transforms generic inventory into committed “Work in Progress” (WIP). It represents the digital assignment of specific material lots to a specific demand (Work Order). Accurate kitting is fundamental to a smooth production run; if operators have to search for missing parts or decipher unclear labels, the line stops. The goal is to provide a comprehensive, verified kit that allows assembly to proceed without interruption.

Picking: the physical transaction

Picking should be a system-validated procedure. Relying on digital scans helps eliminate visual sorting errors.

• The Scan Logic:
  • The Target: The Warehouse Management System (WMS) directs the operator to the Location, specifying the Manufacturer Part Number (MPN) and the required Lot (following First Expired, First Out (FEFO) rules).
  • The Action: The operator scans the Bin Location label, then the Part ID barcode.
  • The Validation:
    • If the scans match the requirement, the quantity is deducted from the bin and transferred to WIP.
    • If the scan fails (e.g. incorrect Lot or Revision), the system should halt the transaction. Operator overrides should be restricted to maintain data integrity.
• Quantity Management:
  • Full Reels: The complete reel must be picked whenever possible. Cutting tape must be avoided unless necessary for a split-build.
  • Exact Count: For high-value or highly controlled items (e.g. CPUs, custom modules), the count must be verified precisely.
  • Bulk/Passives: Inexpensive components must be issued by weight or as full strips/packs to minimize handling time. The labor cost of manually counting dozens of inexpensive resistors often exceeds the value of the components themselves.

Kitting & verification (the “staging” gate)

After picking, materials are consolidated in the Staging Area prior to line release.

• The Kit Cart Preparation:
  • The physical materials on the cart must be organized to logically match the SMT machine setup (e.g. sequencing reels to align with feeder slots 1 through 20).
  • ESD Compliance: It must be ensured the kit cart functions as an Electrostatic Protected Area (EPA) and is properly grounded.
• High-Value (A-Part) Verification:
  • For critical components, a two-person validation step should be considered.
  • The Protocol: The Picker stages the part, and a Quality Lead or secondary operator countersigns or systemically verifies the critical line items against the Bill of Materials (BOM).
• The “Clean Kit” Release:
  • The Goal: Release kits to the floor only when they are complete and clearly documented.
  • Documentation: Standard documentation must be included with the kit, such as the Pick List, relevant Assembly Drawings, and any approved Deviation or Substitution authorizations.

Exception handling: shortages & substitutions

In a real-world environment, production may occasionally begin with known shortages. This must be managed transparently.

• Managing Known Shortages:
  • The Protocol: If a kit is released to the floor with a shortage, the missing item must be highlighted clearly (e.g. in RED) on the physical paperwork and it must be ensured it is digitally flagged in the Manufacturing Execution System (MES).
  • The Goal: A situation where a line operator unexpectedly discovers a missing part mid-run must be prevented.
• Managing Substitutions:
  • The Protocol: If an alternate component is authorized for use, the Work Order BOM must be formally updated in the ERP to reflect the change before the material is issued.
  • The Risk: If the BOM specifies “Part A” but the warehouse issues “Part B,” the traceability record is fundamentally broken.

Pro-Tip: The handover from the Warehouse to Production represents a transfer of ownership. When Production signs for the kit, they assume operational accountability for those materials.

Final Checkout: Picking, kitting & line release discipline

Control Point	Process Requirement	Operational Metric / Target
Pick Accuracy	Utilize scanner enforcement; limit manual overrides.	Target Pick Error Rate: < 100 PPM.
Kit Completeness	Track the percentage of kits released without shortages.	First Pass Kit Yield: > 95%.
Line Release	Kits undergo validation before leaving staging.	Goal: 0 material-caused line stops.
Traceability	Update the BOM to reflect authorized substitutions.	100% BOM accuracy to physical build.
Handover Protocol	Production formally acknowledges receipt of the kit.	Maintains a clear chain of custody.