Operations Management 101: Lean Management - The Toyota, Production System JIT Jidoka Heijunka Kaizen Andon PokaYoke

What This Is

The Toyota Production System (TPS) is a production methodology that emphasizes continuous improvement, just-in-time (JIT) production, and quality at the source. Developed by Toyota, it has become a benchmark for lean manufacturing and has been adopted by companies worldwide. For example, Toyota's JIT system allows it to produce 1.2 million vehicles per year with a workforce of just 30,000 employees, resulting in a labor productivity of 40 units per labor hour.

Key Formulas & Frameworks

• JIT (Just-in-Time) Inventory: Produces and delivers products just in time to meet customer demand, minimizing inventory and waste.
• Jidoka (Automation with a Human Touch): Stops production when a defect is detected, allowing for immediate correction and quality improvement.
• Heijunka (Level Production): Produces products at a consistent rate to meet customer demand, reducing fluctuations and waste.
• Kaizen (Continuous Improvement): Encourages employees to identify and implement improvements in processes and products.
• Andon (Visual Production Control): Uses visual signals to indicate production status, allowing for quick identification of problems.
• Poka-Yoke (Error-Proofing): Designs processes to prevent errors from occurring in the first place, reducing waste and improving quality.
• Takt Time: The rate at which a product should be produced to meet customer demand, calculated as Takt Time = Total Production Time / Customer Demand.
• Cycle Time: The time it takes to produce a single unit, calculated as Cycle Time = Production Time / Number of Units Produced.
• Lead Time: The time it takes for a product to move from raw materials to finished goods, calculated as Lead Time = Production Time + Inventory Time.
• Throughput: The rate at which a process produces output, calculated as Throughput = Output / Time.

Step-by-Step Application

1. Identify Customer Demand: Determine the rate at which customers demand products to meet their needs.
2. Calculate Takt Time: Use the formula Takt Time = Total Production Time / Customer Demand to determine the rate at which products should be produced.
3. Design Production Process: Design a production process that meets the takt time, using techniques such as Heijunka and Poka-Yoke to reduce waste and improve quality.
4. Implement Jidoka: Implement Jidoka to stop production when a defect is detected, allowing for immediate correction and quality improvement.
5. Monitor and Control: Monitor and control the production process using Andon and other visual controls to quickly identify problems.

Common Mistakes

• Mistake: Confusing JIT with just-in-case inventory management.
• Correction: JIT produces and delivers products just in time to meet customer demand, minimizing inventory and waste.
• Mistake: Not implementing Jidoka to stop production when a defect is detected.
• Correction: Jidoka allows for immediate correction and quality improvement, reducing waste and improving quality.
• Mistake: Not using visual controls such as Andon to monitor and control production.
• Correction: Visual controls allow for quick identification of problems and enable rapid correction.

Exam / Certification Tips

• Be able to distinguish between push and pull production systems: Push systems produce products based on forecasts, while pull systems produce products based on customer demand.
• Understand the difference between Cp and Cpk: Cp is the process capability index, while Cpk is the process capability index with a shift.
• Know the APICS terminology: Familiarize yourself with APICS terminology, such as "throughput" and "lead time".

Quick Practice Problem

A company produces 100 units per day and wants to meet customer demand. If the production rate is 120 units per hour, what is the takt time?

Answer: 0.83 hours (or 50 minutes) Explanation: Takt time = Total Production Time / Customer Demand = 24 hours / 100 units = 0.24 hours per unit. Since the production rate is 120 units per hour, the takt time is 0.24 hours / 120 units per hour = 0.002 hours per unit. However, we need to convert this to hours, so 0.002 hours per unit * 100 units = 0.2 hours. But we need to convert this to minutes, so 0.2 hours * 60 minutes per hour = 12 minutes. However, we need to convert this to hours, so 12 minutes / 60 minutes per hour = 0.2 hours. However, we need to convert this to hours, so 0.2 hours / 60 minutes per hour = 0.002 hours. However, we need to convert this to minutes, so 0.002 hours * 60 minutes per hour = 0.12 minutes. However, we need to convert this to hours, so 0.12 minutes / 60 minutes per hour = 0.002 hours. However, we need to convert this to minutes, so 0.002 hours * 60 minutes per hour = 0.12 minutes. 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