Lean Manufacturing · Standard Work

Kanban Card System For Assembly Parts

Establish a disciplined pull-based replenishment system using visual kanban cards to control inventory, eliminate overproduction, and ensure uninterrupted assembly flow. This SOP defines the complete lifecycle from card creation to closed-loop audit.

Estimated Time

45 min

Difficulty

Intermediate

Regulation

Lean / JIT Standard

Version

2.1

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Purpose

To define a standardized method for creating, placing, using, and replenishing kanban cards for assembly parts. This system enables a true pull-based production flow, reduces work-in-process inventory, eliminates shortages at the line, and creates visual accountability for every part in the assembly area. When followed consistently, the kanban system prevents overproduction — the single largest source of waste in lean manufacturing — while ensuring operators never stop assembly due to missing components.

Scope

This procedure applies to all assembly workstations and parts supermarkets within the production floor that operate under kanban replenishment. It covers every stage of the kanban lifecycle: card template design and data entry, lamination and physical placement at the point of use, the consumption signal when the first part is withdrawn, the material handler's retrieval and sorting process, the replenishment pick from the supermarket, and the final card return and loop closure. Also included are the weekly audit requirements to maintain card accuracy and cycle-time discipline. This SOP does not cover electronic kanban systems, supplier (external) kanban, or batch-and-queue scheduling methods.

Safety Precautions

LOTOLockout/Tagout (LOTO): Before accessing any powered storage racks, vertical carousels, or automated retrieval systems, perform full LOTO per facility procedure. Never reach into moving equipment to retrieve a kanban card or bin.
PPEPersonal Protective Equipment: Safety glasses and steel‑toed boots are mandatory in all parts supermarket and assembly aisle zones. Cut‑resistant gloves (ANSI A3 minimum) must be worn when handling metal or sharp‑edged parts bins.
LIFTSafe Lifting: Use mechanical assist (cart, pallet jack, hoist) for any bin exceeding 23 kg (50 lb). For manual lifts, follow the power‑zone technique: keep the load close, bend at the knees, and avoid twisting. Request a second person for awkward or oversized totes.
5SHousekeeping & 5S: Maintain clear, unobstructed access to all kanban card holders and signal posts. No tools, scrap, or personal items may block the visual signal path. Report any damaged or illegible cards immediately to the team lead.

Required Tools & Materials

Kanban cards (laminated, standard size 10 cm × 15 cm / 4" × 6") — printed with part number, part name, bin quantity, card number, supplier code, and storage location
Adhesive‑backed transparent card holders / pockets (sized to fit the kanban card)
Permanent marker, fine tip, black (for manual updates or corrections)
Laminator and laminating pouches (or pre‑laminated card stock)
Standardized parts bins or totes (colour‑coded by part family where applicable)
Designated kanban storage racks or flow racks with clearly labelled location tags
Signal post or card collection box at each assembly workstation
Barcode labels and a hand‑held scanner (optional — required for digital kanban tracking)
Kanban audit checklist (printed or digital) for weekly cycle‑time and card‑accuracy checks

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Procedure: Step-by-Step

1 Card Creation & Data Entry — Use the approved kanban template (available digitally or as a pre‑printed form). Fill in: part number (exact match to BOM), part name, bin quantity (standard lot size), card sequence number (e.g. 1 of 3), supplier or internal source code, and the supermarket/buffer storage location. Verify all fields against the current bill of materials. Print on 120 gsm card stock.

2 Lamination & Placement — Laminate the printed card for protection against oil, moisture, and shop‑floor wear. Affix a transparent adhesive holder to the front face of the designated parts bin — centred, approximately 25 mm from the top edge. Insert the card with the printed side facing outward so it is legible from a standing position. Ensure no adjacent bin obscures the card.

3 Consumption Signal — When the operator removes the first part from a full bin, they must immediately pull the kanban card from its holder and place it in the signal post or collection box at the workstation. This single action is the visual pull signal. Critical rule: never remove the card when the bin is empty — only when the first piece is withdrawn. This ensures the signal fires early enough to prevent a stock‑out.

4 Card Retrieval & Sorting — The material handler (or designated team leader) collects all cards from every signal post at scheduled intervals: every 30 minutes during peak production or at a minimum once per shift. If using a digital system, scan the barcode on each card with a hand‑held scanner to log the signal timestamp. Sort collected cards by supplier, part family, or supermarket zone to optimize the picking route.

5 Replenishment Pick — Take the sorted cards to the parts supermarket or warehouse. For each card, pick the exact bin quantity printed on the card (no more, no less). Place the parts into a clean, standardized bin and re‑affix the kanban card to the front face of the full bin. Stage completed bins in the dispatch lane designated for that assembly line. Update the inventory system if a digital kanban is active.

6 Card Return & Loop Closure — Deliver the replenished bin directly to the assembly workstation. Verify the bin is placed in its correct location (matching the location code on the card) and that the card is facing outward and unobstructed. The material handler initials and dates the back of the card to close the replenishment loop. Weekly audit: inspect 100 % of active cards for legibility, correct quantity, and cycle time (time from signal to delivery should not exceed target — record and escalate any card exceeding the target by more than 20 %).

Kanban Card System For Assembly Parts

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