just in time manufacturing

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JIT is a long-term approach to process improvement. Itcosts, improve quality and improve responsivene uses timeliness as a lever to lower ss. However, JIT requires enormous commitment. It took Toyota more than 25 years to get right!

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  • Ravindra"s presentation
  • just in time manufacturing

    1. 2. <ul><li>The philosophy of JIT can be traced back to Henry Ford, but formalized JIT originated in Japan as the Toyota Production System. W. Edwards Deming’s lesson of variability reduction was a huge influence. </li></ul>2/22/2009 just in time by ravindra The focus of JIT is to improve the system of production by eliminating all forms of WASTE. JIT is a long-term approach to process improvement. It uses timeliness as a lever to lower costs, improve quality and improve responsiveness. However, JIT requires enormous commitment. It took Toyota more than 25 years to get right!
    2. 3. <ul><li>Zero Defects : Quality at the source </li></ul><ul><li>Zero Lot Size : To avoid batching delays </li></ul><ul><li>Zero Setups : To minimize setup delay and allow production in small lots </li></ul><ul><li>Zero Breakdowns : To avoid stopping tightly coupled line </li></ul><ul><li>Zero Handling : To promote flow of parts </li></ul><ul><li>Zero Lead Time : To ensure rapid replenishment of parts </li></ul><ul><li>Zero Surging : Necessary in system without WIP buffers. </li></ul>2/22/2009 just in time by ravindra Waste exists unless all the following goals are achieved
    3. 4. <ul><li>Traditional </li></ul><ul><li>Goal: maximize production by minimizing disruptions </li></ul><ul><li>Management Assumption: we can sell what we make </li></ul><ul><li>Manufacturing Objectives: </li></ul><ul><ul><li>Spread resources evenly: line balancing </li></ul></ul><ul><ul><li>Decouple operations: line pacing and extensive scheduling </li></ul></ul><ul><ul><li>Dependable and efficient operations: automation and forecasting </li></ul></ul><ul><li>JIT </li></ul><ul><li>Goal: Produce salable goods as quickly and efficiently as possible </li></ul><ul><li>Management Assumption: we make what we can sell </li></ul><ul><li>Manufacturing Objectives: </li></ul><ul><ul><li>Clean up the workplace (5Ss) </li></ul></ul><ul><ul><li>Flow manufacturing: GT/CM and cross training </li></ul></ul><ul><ul><li>Level production with visual control: JIT, kanban, SPC </li></ul></ul><ul><ul><li>Manpower reduction </li></ul></ul>2/22/2009 just in time by ravindra
    4. 5. <ul><li>Reduces inventory </li></ul><ul><li>Reduces lead time </li></ul><ul><li>Reduces setup time </li></ul><ul><li>Emphasizes product-oriented layout </li></ul>2/22/2009 just in time by ravindra Just-in-Time Manufacturing Traditional Manufacturing Increases inventory to protect against process problems Increases lead time to protect against uncertainty Disregards setup time as an improvement priority Emphasizes process-oriented layout Just-in-Time Principles
    5. 6. <ul><li>Emphasizes team-oriented employee involvement </li></ul><ul><li>Emphasizes pull manufacturing </li></ul><ul><li>Emphasizes zero defects </li></ul><ul><li>Emphasizes supplier partnering </li></ul>2/22/2009 just in time by ravindra Just-in-Time Manufacturing Traditional Manufacturing Emphasizes work of individuals, following manager instructions Emphasizes push manufacturing Tolerates defects Treats suppliers as “arms-length,” independent entities
    6. 7. <ul><li>The main benefits of JIT are listed below. </li></ul><ul><li>Set up times are significantly reduced in the factory. Cutting down the set up time to be more productive will allow the company to improve their bottom line to look more efficient and focus time spent on other areas that may need improvement. This allows the reduction or elimination of the inventory held to cover the &quot;changeover&quot; time, the tool used here is SMED </li></ul><ul><li>The flows of goods from warehouse to shelves are improved. Having employees focused on specific areas of the system will allow them to process goods faster instead of having them vulnerable to fatigue from doing too many jobs at once and simplifies the tasks at hand. Small or individual piece lot sizes reduce lot delay inventories which simplifies inventory flow and its management. </li></ul><ul><li>Employees who possess multiple skills are utilized more efficiently. Having employees trained to work on different parts of the inventory cycle system will allow companies to use workers in situations where they are needed when there is a shortage of workers and a high demand for a particular product. </li></ul>2/22/2009 just in time by ravindra
    7. 8. <ul><li>Better consistency of scheduling and consistency of employee work hours. If there is no demand for a product at the time, workers don’t have to be working. This can save the company money by not having to pay workers for a job not completed or could have them focus on other jobs around the warehouse that would not necessarily be done on a normal day. </li></ul><ul><li>Increased emphasis on supplier relationships. No company wants a break in their inventory system that would create a shortage of supplies while not having inventory sit on shelves. Having a trusting supplier relationship means that you can rely on goods being there when you need them in order to satisfy the company and keep the company name in good standing with the public. </li></ul><ul><li>Supplies continue around the clock keeping workers productive and businesses focused on turnover. Having management focused on meeting deadlines will make employees work hard to meet the company goals to see benefits in terms of job satisfaction, promotion or even higher pay. </li></ul>2/22/2009 just in time by ravindra
    8. 9. 2/22/2009 just in time by ravindra Flow with JIT Traditional Flow Customers Suppliers Customers Suppliers Production Process (stream of water) Inventory (stagnant ponds) Material (water in stream)
    9. 10. <ul><li>The goal of JIT is to eliminate waste in all its forms. </li></ul><ul><li>The goal is no longer to minimize disruptions </li></ul><ul><li>The assumption of JIT is that we cannot sell everything we make. Thus, we must produce salable goods (low cost, high quality, etc...) quickly. </li></ul><ul><li>Operation = Motion (Waste) + Work (Added Value) </li></ul><ul><li>Motion alone is a waste that adds cost (counting things, moving boxes, transporting goods, preparation time, waiting, producing defects, over production, handling materials, switching things on) </li></ul><ul><li>Inventory decouples individual operations and thereby creates waste (non-value-added motion) to buffer the operations against the effect of a different form of waste (long setups, poor material handling procedures, production of defects, etc.) </li></ul><ul><li>For real improvement, we must ask &quot;why&quot; when we encounter any form of waste. </li></ul>2/22/2009 just in time by ravindra Step 1: Awareness
    10. 11. The role of inventory in traditional and JIT systems: The water and the rocks metaphor Material quality problems Long setups Poor training Break downs Material handling Traditional systems use inventory (water) to buffer the process from problems (rocks) that cause disruption. Water = Inventory 2/22/2009 just in time by ravindra
    11. 12. The role of inventory in traditional and JIT systems: The water and the rocks metaphor Material quality problems Long setups Poor training Break downs Material handling JIT systems view inventory as waste and work to lower inventory levels to expose and correct the problems (rocks) that cause disruption. 2/22/2009 just in time by ravindra
    12. 13. The role of inventory in traditional and JIT systems: The water and the rocks metaphor Material quality problems Long setups Poor training Break downs Material handling Lowering the level of inventory is relatively easy to do. However, the problems that arise must be corrected quickly … Otherwise, without decoupling inventory, the process will flounder. 2/22/2009 just in time by ravindra
    13. 14. <ul><li>Seiri: Proper arrangement (sort through and sort out, identify what you need, discard what you do not need ) </li></ul><ul><li>Seiton: Orderliness (assign a separate location for all essential items) </li></ul><ul><li>Seiso: Cleanliness (keep the workplace spotless at all times) </li></ul><ul><li>Seiketsu: Cleanup (maintain equipment and tools) </li></ul><ul><li>Shitsuke: Discipline (stick to the rules scrupulously) </li></ul>2/22/2009 just in time by ravindra Step 2: Workplace Improvement (the 5 S’s)
    14. 15. <ul><li>Place the machines in process sequence </li></ul><ul><li>Design a cellular (U-shaped) layout </li></ul><ul><li>Make one piece at a time in the cell </li></ul><ul><li>Crosstrain workers to handle multiple processes </li></ul><ul><li>Produce according to the cycle time </li></ul><ul><li>Have the operators work standing up and walking </li></ul><ul><li>Use slower, dedicated machines that are smaller and less expensive </li></ul>2/22/2009 just in time by ravindra Step 3: Flow Manufacturing (one piece at a time)
    15. 16. <ul><li>Promote flow with little WIP </li></ul><ul><li>Facilitate workers staffing multiple machines </li></ul><ul><li>U-shaped cells </li></ul><ul><ul><ul><li>Maximum visibility </li></ul></ul></ul><ul><ul><ul><li>Minimum walking </li></ul></ul></ul><ul><ul><ul><li>Flexible in number of workers </li></ul></ul></ul><ul><ul><ul><li>Facilitates monitoring of work entering and leaving cell </li></ul></ul></ul><ul><ul><ul><li>Workers can conveniently cooperate to smooth flow and address problems </li></ul></ul></ul>2/22/2009 just in time by ravindra Cellular Layout Inbound Stock Outbound Stock
    16. 17. 2/22/2009 just in time by ravindra An engineering and manufacturing philosophy that identifies physical similarities of parts and establishes their effective production. Assignment of individual products to product families
    17. 18. 2/22/2009 just in time by ravindra Assignment of product families to manufacturing cells
    18. 19. 2/22/2009 just in time by ravindra
    19. 20. 2/22/2009 just in time by ravindra Cell A Cell B Cell C Cell D Family 1 Family 2 Family 3 Family 4
    20. 21. <ul><li>Calculate cycle time based on daily volumes </li></ul><ul><li>Detail the order and number of items being made on the line </li></ul><ul><li>Shorten changeover times between the items </li></ul><ul><li>Create a smooth flow </li></ul><ul><li>Deliver information and parts to the line several times a day </li></ul><ul><li>Production Sequence: </li></ul><ul><ul><li>Mix of 50% A, 25% B, 25% C in daily production of 500 units </li></ul></ul><ul><ul><ul><ul><ul><li>0.5  500 = 250 units of A </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>0.25  500 = 125 units of B </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>0.25  500 = 125 units of C </li></ul></ul></ul></ul></ul><ul><ul><li>A – B – A – C – A – B – A – C – A – B – A – C – A – B – A – C … </li></ul></ul>2/22/2009 just in time by ravindra Step 4: Level Production (make the same quantity every day)
    21. 22. <ul><li>Efficient arrangements of people, products and machines </li></ul><ul><li>Standardize cycle time </li></ul><ul><li>Standardize work sequence (standard operations bulletins, standard route sheets, work method manuals) </li></ul><ul><li>Standardize stock-on-hand (Kanban) </li></ul>2/22/2009 just in time by ravindra Step 5: Improve and standardize (produce quality safely and inexpensively)
    22. 23. 2/22/2009 just in time by ravindra … Lower Level Inven-tory … MRP – Push System Kanban – Pull System … Kanban Signals Full Containers Lower Level Inven-tory Assem-bly Assem-bly
    23. 24. 2/22/2009 just in time by ravindra <ul><li>Traditionally, the number of kanbans (N) required at an operation is a function of : </li></ul><ul><li>The demand rate for specific product from downstream workcenters </li></ul><ul><li>The operation’s safety stock level </li></ul><ul><li>The average amount of time it takes to receive WIP from upstream workcenter </li></ul><ul><li>The size of the container attached to each kanban </li></ul>Operation Kanban Kanban Kanban Kanban Kanban Kanban Kanban Demand rate (D) Lead time (T) Safety stock (S) Container size (C) Example, Demand = 1000 units/hour Lead time = 10 minutes = 1/6 hour Container size = 5 parts Safety stock = 5% = .05(1000*1/6) = 8.33 units Equation: N= (DT+S)/C (1000(1/6) + 8.33)/5 = 35
    24. 25. <ul><ul><li>The production environment itself is a control </li></ul></ul><ul><ul><li>Operational details matter strategically </li></ul></ul><ul><ul><li>Controlling WIP is important </li></ul></ul><ul><ul><li>Speed and flexibility are important assets </li></ul></ul><ul><ul><li>Quality can come first </li></ul></ul><ul><ul><li>Continual improvement is a condition for survival </li></ul></ul>2/22/2009 just in time by ravindra
    25. 26. 2/22/2009 just in time by ravindra

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