JIT (Just-in-Time) Manufacturing

This topic is part of the SG Systems Global operations & compliance glossary.

Updated October 2025 • Lean Production • See also: Heijunka, FIFO, FEFO, Poka-Yoke, GS1/GTIN, EPCIS, EDI

Just-in-Time (JIT) is a production and inventory management philosophy that aims to deliver the right materials, in the right quantity, to the right place, at the right time—and nothing more. JIT reduces waste by shrinking buffers, shortening lead times, and exposing process problems that large inventories tend to hide. It is often paired with heijunka (production leveling), poka-yoke (error-proofing), and visual controls (kanban), with a heavy reliance on accurate master data, supplier reliability, and disciplined material flow controls like FIFO or FEFO to prevent aging or obsolescence. In regulated industries, JIT must also respect quality gates such as Hold & Release, Component Release, and Finished Goods Release, ensuring that speed does not compromise traceability or compliance.

“JIT is not about starving the factory—it’s about synchronizing demand, materials, and capacity so that flow replaces firefighting.”

1) What It Is (Unbiased Overview)

At its core, JIT transforms a push system—which builds to forecast—into a pull system, where downstream consumption triggers upstream replenishment. Rather than stockpiling components “just in case,” the factory relies on short, frequent deliveries, small batch sizes, and tight changeovers. This approach encourages standardized work, total productive maintenance, and clear takt time targets that align capacity with demand. To prevent shortages or defects from rippling through the line, JIT uses problem-surfacing mechanisms (andon, escalation paths, stop-the-line culture) and fast root-cause analysis (CAPA) so that issues are fixed at the source rather than buffered by inventory. In regulated sectors (food, pharma, medical devices), JIT is implemented alongside quality controls such as Incoming Inspection, Identity Testing, In-Process Controls, and documented batch records (eBR/eBMR) so that flow is safe as well as fast.

2) Core Building Blocks

Production leveling (heijunka). JIT depends on stable, predictable flow; heijunka smooths the schedule to reduce peaks and valleys that cause expediting, overtime, and inventory surges. Leveling often requires changeover reduction (SMED), flexible staffing, and common tooling. Small batches & takt alignment. Batch sizes shrink to match takt time and customer cadence, decreasing WIP and revealing bottlenecks. Material flow discipline. FIFO lanes, FEFO for perishables, standard containers, and clearly marked bin locations reduce mispicks and aging stock. Kanban signals. Cards, bins, or electronic triggers replenish only what was consumed; maximums and minimums are tuned regularly. Quality at the source. Error-proofing (poka-yoke), layered process audits, and SPC control limits minimize rework loops. Supplier integration. Short lead times, frequent deliveries, standardized packaging/labels (GS1/GTIN), and event-based visibility (EPCIS) turn the extended supply chain into a single synchronized system; formal EDI messages reduce latency and transcription errors.

3) Inventory, Warehousing & Traceability Under JIT

While JIT aims to minimize inventory, it does not eliminate controls—if anything, the remaining stock must be more visible and reliable. Receiving teams practice Dock-to-Stock with rapid QA gating (Component Release) and clear quarantine status. Accurate counts are sustained with Cycle Counting and Inventory Accuracy metrics; Directed Picking and Dynamic Lot Allocation ensure the right lot is pulled every time. End-to-end traceability is non-negotiable: Batch-to-Bin Traceability and Batch Genealogy link each consumption event to downstream batches and, ultimately, to the customer CoA and release history. For date-sensitive goods, Expiration & Shelf-Life Control rules automatically block expired/near-expired lots and promote FEFO pulls.

4) Quality & Compliance Considerations

Lean speed must coexist with regulated discipline. Electronic records and signatures under 21 CFR Part 11 (and EU Annex 11) protect data integrity (ALCOA+) with secured audit trails. For food and beverage, preventive controls and HACCP plans align IPC checks with leveled production; for pharma and APIs, JIT ties into GMP/cGMP, ICH Q10, and ICH Q7 expectations on change control, validation, and release. In medical devices, ISO 13485 connects JIT component control to device DHR completeness. Across domains, robust Change Control and CSV (per GAMP 5) ensure that schedule or parameter tweaks do not silently degrade the validated state. Continuous monitoring through CPV and SPC detects drift early, while deviation/NC workflows and CAPA close the loop.

5) Typical Pitfalls & How to Avoid Them

• Over-aggressive inventory cuts. Slashing buffers without stabilizing processes causes stockouts. Fix: level the schedule, reduce changeover times, and pilot smaller kanban sizes progressively.
• Unreliable master data. Wrong lead times, yields, or pack sizes break pull signals. Fix: institute document control for masters and audit routings/BOMs regularly.
• Weak supplier cadence. JIT requires rhythm; erratic deliveries create whiplash. Fix: collaborate via EDI, forecast sharing, milk-runs, and standardized GS1 labels.
• Poor lot rotation. Without enforced FIFO/FEFO, slow movers quietly expire. Fix: use system-driven directed picking and expiry holds.
• Hidden quality queues. QA backlogs defeat JIT. Fix: align IPC, sampling, and Hold & Release timing with leveled production.
• Digital blind spots. Manual signals lag; errors accumulate. Fix: enable live production visibility and scan-based consumption with audit trails.

6) How This Fits with V5

V5 by SG Systems Global operationalizes JIT by connecting planning signals to physical material movements and compliant quality gates. At receiving, Goods Receipt automatically assigns quarantine status, prints GS1/GTIN labels, and books stock to the correct bin. Incoming Inspection and Identity Testing are scheduled with sample labels and tracked to approval; Hold & Release rules prevent early use. On the floor, e-kanban replenishment uses scan events, dynamic lot allocation, and directed picking to enforce FIFO/FEFO. Operator workflows in eBR/eBMR guide setup, weights, and IPC checks with poka-yoke prompts and audit trails. Exceptions trigger NC and route to CAPA; trends feed CPV and SPC dashboards. Integration to ERP via EDI keeps planning synchronized; visibility extends to suppliers using EPCIS events. Downstream, Finished Goods Release compiles data into CoAs and shipping documents with full genealogy.

7) FAQ

Q1. Is JIT only for high-volume, low-mix?
No. While high-volume lines see quick wins, mixed-model environments can implement JIT through heijunka, flexible cells, and rapid changeovers. Start by leveling the largest volume families and extend iteratively.

Q2. How does JIT interact with quality release gates?
JIT does not skip QA; it synchronizes it. Align sampling, IPC, and Hold & Release timings with leveled plans so that approvals land before the line needs the parts.

Q3. What if suppliers can’t deliver daily?
Use milk-runs, cross-docks, and route pools to consolidate frequent deliveries. Where needed, place a small supermarket near the line and replenish it via EDI forecasts and consumption signals.

Q4. Can JIT work with strict expiry or cold-chain?
Yes—JIT often improves freshness. Enforce FEFO, temperature zoning, and automated expiry controls so only compliant lots flow to production.

Q5. How do we set kanban sizes?
Start with demand rate × replenishment lead time × safety factor. Then reduce incrementally as reliability and changeover performance improve; confirm with cycle count accuracy and stockout analysis.

Q6. What metrics show JIT is working?
Lead time, on-time-in-full, line stoppages per day, WIP turns, schedule adherence, pick accuracy, expiry scrappage, and first-pass yield. In regulated plants, add deviation rate, SPC capability indices, and batch review cycle time.

Q7. Is JIT risky in volatile demand?
JIT reduces buffer, so volatility must be managed with leveled mix, late customization, and capacity buffers. Keep a clearly defined strategic buffer for true demand spikes while still running the day-to-day via pull.

Related Reading
• Flow & Scheduling: Heijunka | Live Production Visibility | Poka-Yoke
• Materials & Traceability: GS1/GTIN | EPCIS | Batch-to-Bin Traceability | Batch Genealogy
• Warehouse & Control: Dock-to-Stock | Directed Picking | Dynamic Lot Allocation | Inventory Accuracy
• Quality & Compliance: In-Process Controls | Hold & Release | Finished Goods Release | 21 CFR Part 11 | GAMP 5 | ISO 13485 | GMP / cGMP