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Operations Management PowerPoint Presentation
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Operations Management

Operations Management

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Operations Management

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  1. Operations Management Chapter 16 – JIT and Lean Operations PowerPoint presentation to accompany Heizer/Render Principles of Operations Management, 7e Operations Management, 9e Some additions and deletions have been made by Ömer Yağız to this slide set.

  2. Outline • Global Company Profile: Toyota Motor Corporation • Just-in-Time, the Toyota Production System, and Lean Operations • Eliminate Waste • Remove Variability • Improve Throughput

  3. Outline – Continued • Just-in-Time • JIT Partnerships • Concerns of Suppliers • JIT Layout • Distance Reduction • Increased Flexibility • Impact on Employees • Reduced Space and Inventory

  4. Outline – Continued • JIT Inventory • Reduce Variability • Reduce Inventory • Reduce Lot Sizes • Reduce Setup Costs • JIT Scheduling • Level Schedules • Kanban

  5. Outline – Continued • JIT Quality • Toyota Production System • Continuous Improvement • Respect for People • Standard Work Practices • Lean Operations • Building a Lean Organization • Lean Operations in Services

  6. Learning Objectives When you complete this chapter you should be able to: Define just-in-time, TPS, and lean operations Define the seven wastes and the 5 Ss Explain JIT partnerships Determine optimal setup time

  7. Learning Objectives When you complete this chapter you should be able to: Define kanban Compute the required number of kanbans Explain the principles of the Toyota Production System

  8. Toyota Motor Corporation • Largest vehicle manufacturer in the world with annual sales of over 9 million vehicles • Success due to two techniques, JIT and TPS • Continual problem solving is central to JIT • Eliminating excess inventory makes problems immediately evident

  9. Toyota Motor Corporation • Central to TPS is a continuing effort to produce products under ideal conditions • Respect for people is fundamental • Small building but high levels of production • Subassemblies are transferred to the assembly line on a JIT basis • High quality and low assembly time per vehicle

  10. Toyota Prod System (TPS) became Lean Manuf System in the USA

  11. Just-In-Time, TPS, and Lean Operations • JIT is a philosophy of continuous and forced problem solving via a focus on throughput and reduced inventory • TPS emphasizes continuous improvement, respect for people, and standard work practices • Lean production supplies the customer with their exact wants when the customer wants it without waste

  12. Just-In-Time, TPS, and Lean Operations • JIT emphasizes forced problem solving • TPS emphasizes employee learning and empowerment in an assembly-line environment • Lean operations emphasize understanding the customer

  13. JIT, TPS, and Lean • All are basically used interchangeably • We will refer to all as “Lean Operations “ ; the textbook does the same.

  14. Lean Operations • Doing more with less inventory, fewer workers, less space • Just-in-time (JIT) • smoothing the flow of material to arrive just as it is needed • “JIT” and “Lean Production” are used interchangeably • Muda • waste, anything other than that which adds value to the product or service

  15. Origins of Lean Operations • Japanese firms, particularly Toyota, in 1970's and 1980's • Eiji Toyoda, Taiichi Ohno and Shigeo Shingo( http://en.wikipedia.org/wiki/Eiji_Toyoda ) • Geographical and cultural roots • Japanese objectives • “catch up with America” (within 3 years of 1945) • small lots of many models • Japanese motivation • Japanese domestic production in 1949 --- 25,622 trucks, 1,008 cars • American to Japanese productivity ratio ---9:1 • Era of “slow growth” in 1970's

  16. Three major issues • Effective OM means managers must also address three issues: • eliminate waste • remove variability • improve throughput

  17. Taiichi Ohno’s Seven Wastes • Overproduction (more than demanded) • Queues (idle time, storage, waiting) • Transportation (materials handling) • Inventory (raw, WIP, FG, excess operating supplies) • Motion (movement of people & equipment) • Overprocessing (work that adds no value) • Defective products (rework, scrap, returns, warranty claims)

  18. Eliminate Waste • Waste is anything that does not add value from the customer point of view • Storage, inspection, delay, waiting in queues, and defective products do not add value and are 100% waste

  19. Eliminate Waste • Other resources such as energy, water, and air are often wasted • Efficient, ethical, and socially responsible production minimizes inputs, reduces waste • Traditional “housekeeping” has been expanded to the 5 Ss

  20. The 5 Ss • The method of 5 S's is an important part of Lean. Named after five Japanese concepts, the 5 S's is a set of workplace organization or housekeeping rules for keeping the factory in perfect order. The method is regarded as a prerequisite for Lean. The 5 S's include: • Seiri - sorting, i.e., proper arrangement of all items, storage, equipment, tools, inventory and trafficSeiton - orderlinessSeiso - cleanlinessSeiketsu - standardization, andShitsuke - self-discipline

  21. The 5 Ss • Sort/segregate – when in doubt, throw it out • Simplify/straighten – use methods analysis tools • Shine/sweep – clean daily • Standardize – remove variations from processes (SOP’s and checklists) • Sustain/self-discipline – review work and recognize progress

  22. The 5 Ss • Sort/segregate – when in doubt, throw it out • Simplify/straighten – methods analysis tools • Shine/sweep – clean daily • Standardize – remove variations from processes • Sustain/self-discipline – review work and recognize progress • Two additional Ss • Safety – build in good practices • Support/maintenance – reduce variability and unplanned downtime

  23. Remove Variability • JIT systems require managers to reduce variability caused by both internal and external factors • Variability is any deviation from the optimum process • Inventory hides variability • Less variability results in less waste

  24. Sources of Variability Incomplete or inaccurate drawings or specifications Poor production processes resulting in incorrect quantities, late, or non-conforming units Unknown customer demands

  25. Sources of Variability Incomplete or inaccurate drawings or specifications Poor production processes resulting in incorrect quantities, late, or non-conforming units Unknown customer demands Both JIT and inventory reduction are effective tools in identifying causes of variability

  26. Improve Throughput • The time it takes to move an order from receipt to delivery • The time between the arrival of raw materials and the shipping of the finished order is called manufacturing cycle time • A pull system increases throughput

  27. Improve Throughput • By pulling material in small lots, inventory cushions are removed, exposing problems and emphasizing continual improvement • Manufacturing cycle time is reduced • Push systems dump orders on the downstream stations regardless of the need

  28. Just-In-Time (JIT) • Powerful strategy for improving operations • Materials arrive where they are needed when they are needed • Identifying problems and driving out waste reduces costs and variability and improves throughput • Requires a meaningful buyer-supplier relationship

  29. JIT and Competitive Advantage Figure 16.1

  30. Vendor Fab Sub Vendor Fab Sub Fab Vendor Fab Vendor JIT Logic PULL…. Final Assy Customers 4

  31. JIT and Competitive Advantage Figure 16.1

  32. JIT Partnerships • JIT partnerships exist when a supplier and purchaser work together to remove waste and drive down costs • Four goals of JIT partnerships are: • Removal of unnecessary activities • Removal of in-plant inventory • Removal of in-transit inventory • Improved quality and reliability

  33. JIT Partnerships Figure 16.2

  34. Concerns of Suppliers • Diversification – ties to only one customer increases risk • Scheduling – don’t believe customers can create a smooth schedule • Changes – short lead times mean engineering or specification changes can create problems • Quality – limited by capital budgets, processes, or technology • Lot sizes – small lot sizes may transfer costs to suppliers

  35. JIT Layout Tactics Build work cells for families of products Include a large number operations in a small area Minimize distance Design little space for inventory Improve employee communication Use poka-yoke devices Build flexible or movable equipment Cross-train workers to add flexibility JIT Layout Reduce waste due to movement Table 16.1

  36. Distance Reduction • Large lots and long production lines with single-purpose machinery are being replaced by smaller flexible cells • Often U-shaped for shorter paths and improved communication • Often using group technology concepts

  37. Increased Flexibility • Cells designed to be rearranged as volume or designs change • Applicable in office environments as well as production settings • Facilitates both product and process improvement

  38. Manufacturing Cell With Worker Routes Machines Enter Worker 2 Worker 3 Worker 1 Exit Key: Product route Worker route

  39. Impact on Employees • Employees are cross trained for flexibility and efficiency • Improved communications facilitate the passing on of important information about the process • With little or no inventory buffer, getting it right the first time is critical

  40. Reduced Space and Inventory • With reduced space, inventory must be in very small lots • Units are always moving because there is no storage

  41. JIT Inventory Tactics Use a pull system to move inventory Reduce lot sizes Develop just-in-time delivery systems with suppliers Deliver directly to point of use Perform to schedule Reduce setup time Use group technology Inventory Inventory is at the minimum level necessary to keep operations running Table 16.2

  42. Holding, Ordering, and Setup Costs • Holding costs - the costs of holding or “carrying” inventory over time • Ordering costs - the costs of placing an order and receiving goods • Setup costs - cost to prepare a machine or process for manufacturing an order

  43. Holding Costs Table 12.1

  44. Holding costs vary considerably depending on the business, location, and interest rates. Generally greater than 15%, some high tech items have holding costs greater than 50%. Holding Costs Table 12.1

  45. Inventory Models for Independent Demand Need to determine when and how much to order • Basic economic order quantity • Production order quantity • Quantity discount model

  46. Basic EOQ Model Important assumptions Demand is known, constant, and independent Lead time is known and constant Receipt of inventory is instantaneous and complete Quantity discounts are not possible Only variable costs are setup and holding Stockouts can be completely avoided

  47. Average inventory on hand Q 2 Usage rate Inventory level Minimum inventory 0 Time Inventory Usage Over Time Order quantity = Q (maximum inventory level) Figure 12.3

  48. Curve for total cost of holding and setup Minimum total cost Holding cost curve Annual cost Setup (or order) cost curve Order quantity Optimal order quantity (Q*) Minimizing Costs Objective is to minimize total costs Table 11.5

  49. D Q Annual setup cost = S Annual demand Number of units in each order Setup or order cost per order = = (S) D Q The EOQ Model Q = Number of pieces per order Q* = Optimal number of pieces per order (EOQ) D = Annual demand in units for the inventory item S = Setup or ordering cost for each order H = Holding or carrying cost per unit per year Annual setup cost = (Number of orders placed per year) x (Setup or order cost per order)

  50. D Q Annual setup cost = S Annual holding cost = H Order quantity 2 = (Holding cost per unit per year) = (H) Q 2 Q 2 The EOQ Model Q = Number of pieces per order Q* = Optimal number of pieces per order (EOQ) D = Annual demand in units for the inventory item S = Setup or ordering cost for each order H = Holding or carrying cost per unit per year Annual holding cost = (Average inventory level) x (Holding cost per unit per year)