Introduction

The Toyota Production System House

Two pillars supporting operational excellence

GOAL

Highest Quality • Lowest Cost • Shortest Lead Time

PILLAR 1: JIT

Just-In-Time
Right part
Right time
Right quantity

PILLAR 2: JIDOKA

Autonomation
Built-in quality
Stop on defect
Separate human/machine

FOUNDATION

Heijunka • Standardized Work • Kaizen • 5S • TPM • Visual Management

CENTER

People & Teamwork

What You'll Learn

This guide covers the two pillars of the Toyota Production System (TPS) and the concept of Flow. These are the foundation of Lean Manufacturing used by world-class manufacturers worldwide.

Step 1 of 4

Just-In-Time (JIT)

Produce exactly what's needed, when needed, in the quantity needed

JIT Philosophy

JIT eliminates waste by producing only on customer demand. No overproduction, no excess inventory, no waiting. This is achieved through three core concepts: Pull System, Takt Time, and Continuous Flow.

1. Pull System

Production is "pulled" by customer demand. Downstream process signals upstream when to produce. Opposite of "push" (make to forecast).

Customer orders trigger production (not forecasts)
Downstream process consumes, then signals upstream to replenish
Kanban cards control production authorization
Produce only what's been consumed - no overproduction

2. Takt Time

Takt Time = Available Production Time ÷ Customer Demand
Pace of production synchronized to customer demand rate.

Example:
• Customer orders: 400 units/day
• Available time: 480 min - 30 min breaks = 450 min = 27,000 sec
• Takt Time = 27,000 ÷ 400 = 67.5 seconds per unit
• Every process must complete in ≤67.5 sec to meet demand

3. Continuous Flow

Items move one-at-a-time (or small batches) through processes with no waiting. Eliminates batch-and-queue waste.

One-piece flow whenever possible
Minimal WIP between processes
Balanced cycle times (all processes ≈ takt time)
Problems surface immediately (no inventory to hide them)

JIT Prerequisites (Must Have)

Stable Processes: Reliable equipment (TPM), consistent quality
Quick Changeovers: SMED - setup time <10 minutes
Balanced Production: All process times similar (±10% of takt)
Standard Work: Documented procedures, repeatable methods
Built-in Quality: Jidoka - don't pass defects downstream
Reliable Suppliers: Frequent deliveries, small lots, on-time
Visual Management: Kanban, andon, status boards
Flexible Workforce: Cross-trained, engaged operators

JIT Benefits

• Inventory: 50-90% reduction
• Lead time: 80-95% shorter
• Space: 30-50% less needed
• Quality: Immediate defect detection
• Cash flow: Less capital tied up
• Flexibility: Quick response to demand

JIT Challenges

• Requires process stability first
• Supply chain vulnerability
• Demand volatility difficult
• Cultural change needed
• Takes years to fully implement
• Not a quick fix

Step 2 of 4

Jidoka (Autonomation)

Automation with human intelligence - build quality in

What is Jidoka?

Jidoka (自働化) = "automation with human touch." Machines must have ability to detect abnormalities and stop automatically. This prevents defects, frees operators from babysitting, and builds quality into the process.

Origin Story

Sakichi Toyoda invented an automatic loom in 1896 that stopped itself if a thread broke. This prevented defective fabric and allowed one operator to manage multiple looms. This simple innovation became the foundation of Jidoka.

The Four Steps of Jidoka

Step 1: Detect Abnormality

Sensor, vision system, or quality check detects when something goes wrong

Step 2: Stop Process

Immediate automatic halt. Prevents making more defects. Andon light/alarm signals problem

Step 3: Fix Immediate Problem

Operator or maintenance responds. Fixes specific issue causing the stop

Step 4: Investigate Root Cause

Use 5 Whys or RCA. Implement permanent countermeasure to prevent recurrence

Jidoka Devices & Examples

Limit Switches: Detect position, missing parts, blockages. Stop if not correct
Vision Systems: Cameras inspect 100%. Detect defects, reject automatically
Load Monitors: Detect abnormal current/torque. If too high/low, stop
Andon Cord/Button: Operators pull/push to stop line when problem detected
Poka-Yoke Sensors: Ensure correct assembly. Wrong part won't fit, machine won't start
Guide Pins: Parts must be aligned. Sensor confirms before proceeding
Full-Work System: Machine only starts next cycle when previous complete

Jidoka vs Regular Automation

Regular Automation: Machine runs automatically. If problem, keeps making defects until someone notices. Operator must watch constantly.

Jidoka (Autonomation): Machine runs AND stops on problem. Operator freed. Can manage multiple machines. Quality built-in.

The Difference: Intelligence. Jidoka knows when something's wrong and takes action.

Step 3 of 4

Flow - The Ultimate Goal

Continuous movement of value through the system

What is Flow?

Flow is the ideal state: work moves smoothly from step to step with no waiting, no batching, no queues. Like a river flowing continuously. The opposite is batch-and-queue: work sits in piles.

Batch-and-Queue (No Flow)

• Large batches processed together
• Work piles up between steps
• Long wait times (days/weeks)
• Push system (forecast)
• High WIP inventory
• Defects found late
• Long lead times

Continuous Flow (Ideal)

• One-piece flow (small batches)
• No queues between steps
• Minimal wait (seconds/minutes)
• Pull system (demand)
• Minimal WIP
• Defects caught immediately
• Short lead times

Achieving Flow - 8 Prerequisites

1. Eliminate Major Waste: Remove TIMWOODS - can't flow if clogged
2. Balance Workload: All processes similar time (takt time pacing)
3. Reduce Changeover: SMED - quick setups enable small batches
4. Stabilize Processes: TPM for reliability, Jidoka for quality
5. Right-Size Equipment: Small, flexible machines vs huge batch processors
6. Cellular Layout: U-shape or line arrangement for continuous flow
7. Standard Work: Consistent methods, repeatable processes
8. Visual Management: Problems visible immediately (andon, kanban)

Flow Benefits

Lead Time:
80-95% reduction (weeks → hours)

WIP Inventory:
75-90% less between steps

Floor Space:
40-60% less needed

Quality:
Defects caught immediately

Productivity:
25-50% improvement per person

Flexibility:
Quick response to demand changes

River vs Puddles Analogy

Batch-and-Queue = Puddles: Water sits in puddles (inventory). Evaporates. Stagnant. Eventually flows when full.

Continuous Flow = River: Water flows continuously. No puddles. Fresh, moving. Obstacles immediately visible.

Lean Goal: Turn your process from puddles into a river. When flow achieved, problems become obvious because they immediately disrupt smooth flow.

🏆

TPS Pillars Mastered!

You now understand the two pillars of the Toyota Production System and how they work together to achieve operational excellence.

Knowledge Check

1. What is the main goal of JIT?

A) Reduce costs by any means

B) Produce exactly what's needed, when needed, in quantity needed

C) Maximize machine utilization

2. What makes Jidoka different from regular automation?

A) It's faster

B) Machines detect problems and stop automatically

C) It requires fewer operators

3. What is required to achieve continuous flow?

A) Bigger machines and larger batches

B) More inventory between steps

C) Balanced processes, stable quality, quick changeovers

Implementation Roadmap

Phase 1 (Months 1-3): Stabilize - Implement 5S, TPM, basic problem-solving
Phase 2 (Months 4-6): Standardize - Document standard work, reduce variation
Phase 3 (Months 7-12): Flow - Balance processes, reduce changeovers, cellular layout
Phase 4 (Year 2): Pull - Implement kanban, level production, supplier JIT
Phase 5 (Year 3+): Perfection - Continuous kaizen, zero defects, true TPS

The Two Pillars Working Together

JIT exposes problems by removing inventory buffers. When flow is disrupted, issues are immediately visible.

Jidoka prevents defects from flowing downstream. Quality is built-in, not inspected-in.

Together: JIT creates urgency to solve problems (no buffer to hide them). Jidoka prevents defects from disrupting flow. This combination drives continuous improvement and operational excellence.