1 / 26

Lean Production and the Just-in-Time Philosophy

Lean Production and the Just-in-Time Philosophy. Lean Production. Elimination of All Waste – Waste is Anything that Does Not Add Value to Product. Continuous Improvement of Productivity. Seven Sources of Waste (Toyota). Process – Minimize Scrap, Lot Sizes, Costs

Download Presentation

Lean Production and the Just-in-Time Philosophy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Lean Production and the Just-in-Time Philosophy

  2. Lean Production • Elimination of All Waste – Waste is Anything that Does Not Add Value to Product. • Continuous Improvement of Productivity

  3. Seven Sources of Waste (Toyota) • Process – Minimize Scrap, Lot Sizes, Costs • Methods – Minimize Wasted Motions & Effort • Movement – Minimize Moving & Storing Parts • Defects – Eliminate • Wait Time – Minimize • Overproduction – Eliminate • Inventory – Eliminate or Reduce

  4. Additional Ways to Eliminate Waste • Limited Product Range • Standardization of Components • Poke-Yoke (Fail Safe) • Kaizen • Takt Time • Value Stream Mapping

  5. Value Stream Mapping Example

  6. Just-In-Time (JIT) Is Pursuit of • Zero Inventories • Zero Transactions • Zero “Disturbances” – Routine Execution of Schedule • Total Quality Management (TQM)

  7. How Does JIT Minimize Inventories? 1. Lot-Size Stocks – Allows Routine Batching of Orders and Quantity Discounts • JIT Reduces Set Up and Order Costs by Automation, Group Technology, Contracts. • Lot Sizes and Inventory Are Reduced. • Vendor Contracts Allow Firm to Receive Quantity Discounts without Inventory.

  8. How Does JIT Minimize Inventories? Lot-Size Stocks • Suppose Demand = 5, Holding Cost = $2, and Set Up = $5 Lot Size Holding Set Up Total 1 $1.00 $25.00 $26.00 5* 5.00 5.00 10.00 10 10.00 2.50 12.50 • Q* = 5 and Cost = $10.00

  9. How Does JIT Minimize Inventories? Lot-Size Stocks • Suppose Demand = 5, Holding Cost = $2, and Set Up = $.20 Lot Size Holding Set Up Total 1* $1.00 $1.00 $2.00 5 5.00 0.20 5.20 10 10.00 0.10 10.10 • Q* = 1 and Cost = $2.00

  10. How Does JIT Minimize Inventories? 2. Safety (Buffer) Stocks – Extra Inventory Set Aside for Uncertain Demand or Problems. • JIT Advocates Customer Contracts. • JIT Seeks to Eliminate Problems through Redundancy and Flexible Work Force.

  11. How Does JIT Minimize Inventories? 3. Anticipation (Seasonal)Stocks – Allows Anticipation of Seasonal Surges in Demand. • JIT Advocates Chase Production Planning Strategy. • JIT Reduces Change in Production Costs (Setup, Hiring, Changeover).

  12. How Does JIT Minimize Inventories? 4. TransportationStocks – Inventory in Transit from One Point to Another. • JIT Advocates Reduced Distances between Transit Points.

  13. JIT and Product Design • Quality at the Source • Standard and Modular Parts • Reducing “Real” Levels – Bill of Materials • Design for Cellular Manufacturing

  14. Work Cell Example

  15. Work Cell Example

  16. JIT and Process Design • Setup Time Reduction – Job Shops Become More Like Assembly Lines. • Production Flexibility • Cellular Manufacturing • Process Inventory and Throughput Time Reduction

  17. JIT and Job Design • Skilled and Motivated Work Force • Continual Learning and Improvement • Cross Training • Worker Flexibility • Surge Capacity Must Be Available

  18. JIT Ratio Analysis • Lead Time to Work Content Production Lead Time / Work Content  5 • Process Speed to Sales Rate (Takt Time) Process Speed / Sales Rate or Use  5 • Pieces to Work Stations or Operators Number of Pieces / Number of Stations  5

  19. Kanban Systems Single-Card • One Card per Item, Lot, or Container • Cards in Rack Imply Production on Part • Cards Indicating Assemble Part Can Be Used to Trigger Ordering More Parts

  20. Kanban Systems Two-Card • First Card Is Transport or Withdrawal or Conveyance Card – Placed in Stock of Exiting Part, Authorizes Replacement • Second Card Is Production Card – Placed in Work Center Box to Authorize Production

  21. Kanban Systems

  22. Use of Two-Card Kanban

  23. Kanban Systems • Each Container – Only One Kanban • No Partials – Each Container Filled, Empty, or Being Filled or Empty • Production or Movement Must be Authorized by Kanban

  24. Number of Kanban Containers N = DT(1+X)/C N = Number of Containers (or Cards) D = Demand or Usage Rate T = Mean Waiting or Lead Time for Part Replenishment + Mean Production Time Using Parts X = Inefficiency (1- Efficiency) (0 is Best) C = Capacity of Standard Container

  25. Number of Kanban Containers Example: D = 100 Parts per Hour T = 90 Minutes (1.5 Hours) X = 0.1 C = 84 Parts N = (100)(1.5)(1.1)/84 = 1.96 ≈ 2

More Related