Chapter 7: Lean Thinking and Lean Systems Notes

Chapter 7: Lean Thinking and Lean Systems

Learning Objectives

  • LO 7.1: Describe the origins and evolution of lean thinking.
  • LO 7.2: Describe the five tenets of lean thinking and the seven forms of waste in a lean system.
  • LO 7.3: Explain why a stabilized master schedule is required for smooth flow.
  • LO 7.4: Explain how setup time, lot size, layout, and maintenance are related to lean thinking.
  • LO 7.5: Differentiate how employees are unique in lean systems.
  • LO 7.6: Design a Kanban system to achieve customer pull.
  • LO 7.7: Compare lean suppliers to traditional manufacturing suppliers.
  • LO 7.8: Explain how to implement a lean system.

Evolution of Lean

  • Toyota Production System (TPS): Developed in Japan post-WWII due to resource limitations, also known as Just-in-Time (JIT) manufacturing.
  • Introduced to the U.S. in 1981 at Kawasaki Motorcycle Plant in Lincoln, Nebraska.
  • The 1990s book, "The Machine That Changed the World" by Womack, Jones & Roos popularized the term Lean Production.

Lean Tenets

  • Create Product/Service Value from Customer Perspective: Focus on value as perceived by the customer.
  • Reduce Waste (Muda): Identify and minimize waste in processes.
  • Observe the Process (Gemba): Direct observation of processes for improvement.
  • Ensure Simple, Smooth, Error-Free Flow: Use methods like takt time and kanbans to produce based on customer demand.
  • Strive for Perfection: Continuous improvement techniques such as Kaizen events, 5S, and the 5 Whys.

Seven Forms of Waste

  • Overproduction: Producing more than customer demand; leads to excess inventory.
  • Waiting Time: Idle time for operators/machines; includes customer waiting time.
  • Unnecessary Transportation: Inefficient movement of materials due to poor layout.
  • Excess Processing: Inefficient processes requiring extra resources.
  • Too Much Inventory: Excess stock leading to waste and imbalances in flow.
  • Unnecessary Motion: Wasted movement by personnel, such as walking to retrieve materials.
  • Defects: Resources wasted on faulty products or services that require rework.

Value Stream Mapping

  • Comprehensive mapping of the steps needed to complete a product or service.
  • Includes both value-adding and non-value-adding activities.
  • Visual tool to identify waste by observing processes directly (Gemba).
  • Question to consider: "Is this step necessary for creating customer value?"

Ensuring Flow

  • Inventory Hides Problems: High inventory levels can mask underlying issues within processes.
  • Lower inventory levels can expose problems, allowing for better identification and resolution of issues.

Customer Pull vs. Push Systems

  • Push System: Production occurs based on forecast without specific customer demand.
  • Pull System: Production initiates from customer signals indicating specific demand, reducing excess inventory.

Striving for Perfection

  • Quality is paramount; defects constitute waste. Design systems to unveil errors and address them at their source.
  • Continuous improvement is a cycle ingrained in lean thinking.

5 Whys Technique

  • A method to explore root causes of problems by repeatedly asking why a problem occurs until identifying the root cause.
  • Example: A truck won’t start - uncover cause through questioning until a solution is identified.

5S Technique

  • Sort (Seiri): Keep only necessary items, discard the rest.
  • Straighten (Seiton): Organize and arrange items for easy access.
  • Shine (Seiso): Regular cleaning to ensure a tidy workspace.
  • Standardize (Seiketsu): Establish standards for processes to maintain organization.
  • Sustain (Shitsuke): Maintain discipline to adhere to standards over time.

Creating Flow

  • Stabilizing the master schedule helps align production with demand and retains workload consistency across resources.
  • Strategies include reducing setup times, minimizing lot sizes, using cellular layouts, and cross-training employees.

Kanban Systems

  • Utilizes signals (kanbans) to control inventory and production processes; encourages a pull system.
  • Helps in reducing lead times and preventing inventory buildup.
  • Example calculation to determine the number of containers needed for optimal flow based on demand rate and processing time.

Supplier Relationships

  • View suppliers as extensions of the manufacturing process; favor fewer suppliers to enhance efficiency.
  • Maintain high quality that is trusted rather than inspected.
  • Foster long-term relationships for mutually beneficial partnerships.

Implementation: Kaizen Event

  • Establish cross-functional teams to assess customer values and map out value streams.
  • Identify non-value-adding activities and eliminate waste for smoother processes.
  • Encourage team proposals to implement improvements and sustain lean practices.

Conclusion and Review

  • Review the key principles of lean thinking, tenets, forms of waste, pull systems, and the importance of effective implementation for successful lean operations.