Just in time technology (JIT)
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- Just-in-time (JIT) manufacturing was first developed by Toyota to reduce waste by supplying the right materials to production lines only when needed and in the minimum necessary amounts. It aims to eliminate overproduction and excess inventory that do not add value. - Key aspects of JIT include a pull-based production system controlled through kanban signals, small lot sizes, low setup times, continuous flow, and close partnerships with suppliers. Implementing JIT exposes problems in production so they can be addressed, improving quality over time. It requires stable production schedules and reliable equipment and processes.
Just in time technology (JIT)
- 1. Just in time technology (JIT) Presented by Akash Dutta Department of Mechanical Engineering Indian Institute of Technology Guwahati
- 2. History of JIT • First developed by Toyota • Toyota not only applied JIT to its own production but also to its supplier delivery operations • Before JIT o “just in case” production o Large in-progress inventories to cope with production problems • Other concepts related to JIT- o Continuous flow manufacturing…IBM corporation o Zero inventory production system…General Electric Company o Zero inventory…American Production and Inventory Control Society 9/21/2015 1
- 3. What is JIT? • Supplying "what is needed, when it is needed, and in the amount needed“ • Making "only what is needed, when it is needed, and in the amount needed.“ The philosophy of JIT: “the storage of unused inventory is a waste of resources” Aim: “the right material, at the right time, at the right place, and in the exact amount”, without the safety net of inventory 9/21/2015 2
- 4. Features of JIT • Reduction of wastage • Pull system of production • Use of kanbans • Streamlined production • Flexibility in production • Low inventories • Balanced system: Distribution of the workload evenly among work stations 9/21/2015 3
- 5. Reduction of wastes “Waste is anything other than the minimum amount of equipment, materials, parts, space, and worker’s time, which are absolutely essential to add value to the product” Shoichiro Toyoda Sources of wastes: • Overproduction • Waiting • Unnecessary transportation • Inventory • Inefficient work methods • Inefficient processing • Unnecessary motions • Product defects 9/21/2015 4
- 9. Push system of production • Parts at each workstation are produced irrespective of the need for them in the downstream workstation • Pushes the parts through the plant • More parts get produced than the system can handle • Large work-in-progress inventory • Overloaded factory • Example: material requirement planning (MRP) 9/21/2015 8
- 10. Pull system of production • The order to make and deliver parts at each workstation comes from the downstream station that uses that part • Order placed only when parts are about to be exhausted • Production starts only upon receiving the order • When implemented through the plant has the effect of pulling parts through the system • Minimum work-in-progress inventory • JIT is based on this system • Example: Toyota production system 9/21/2015 9
- 11. Kanban system “kan ban” Card signal 9/21/2015 10 Signal card When to make it! When to move it!
- 12. Two types of kanban signal 1. Production kanban o authorizes the upstream station to produce a batch of parts o the parts produced are placed in containers so that the batch quantity is just sufficient to fill It o production more than this quantity is not allowed 2. Transportation kanban o authorizes the movement of a batch of parts to the next downstream station 9/21/2015 11
- 17. The production kanban signal It tells us: when to make what to make how much to make Types: 1. Production card Instructs us to make One Container 2. Signal (Triangle) Instructs us to produce One Lot Used when a work unit does not have the changeover capability to produce one container for one production card 9/21/2015 16
- 18. Production card information • Store Address • Kanban Signal Number • Work Unit Name • Part Number • Quantity • Card Number 9/21/2015 17
- 19. Signal (Triangle) Information • Work Unit Name • Part Number • Container Type • Quantity • Process Time • Lot Size • Order Point • Kanban Signal Number 9/21/2015 18
- 20. Flow of Production Kanban Signals 9/21/2015 19
- 21. The transportation kanban signal It tells us: when to move what to move where to move how much to move Types: 1. Customer Kanban Signal ->Transfers material from plant to customer 2. Move Kanban Signal -> Transfers material between work units 3. Supplier Kanban Signal -> Pulls material from supplier to plant 9/21/2015 20
- 22. Customer Kanban signal information • Supplier • Quantity • Supplier Number • Card Number • Kanban Signal Number • Container Type • Part Number • Description • Storage Location • Storage Address 9/21/2015 21
- 23. Flow of Customer Kanban Signal 9/21/2015 22
- 24. Move Kanban signal information • Part Number • Supplier Name • Storage Address • Card Number • Kanban Signal Number • Work Unit Name (Customer) • Quantity per Container • Line Address (Point of Use) 9/21/2015 23
- 25. Flow of Move Kanban Signal 9/21/2015 24
- 26. Supplier Kanban signal information • Supplier Name • Part Number • Part Name • Customer • Storage Address • Work Unit Address • Quantity per Container • Card Number • Kanban Signal Number 9/21/2015 25
- 27. Flow of Supplier Kanban Signal 9/21/2015 26
- 28. Kanban rules 1. Customer (downstream) processes withdraw items in the precise amounts specified by the Kanban. 2. Supplier (upstream) produces items in the precise amounts and sequences specified by the Kanban. 3. No items are made or moved without a Kanban. 4. A Kanban should accompany each item, every time. 5. Defects and incorrect amounts are never sent to the next downstream process. 6. The number of Kanbans is reduced carefully to lower inventories and to reveal problems. 9/21/2015 27
- 29. Streamlined production 9/21/2015 28 Flow with JIT Traditional Flow Customers Suppliers Customers Suppliers Production Process (stream of water) Inventory (stagnant ponds) Material (water in stream)
- 30. Inventories • JIT objective: eliminate inventory • JIT requires o Small lot sizes o Low setup time o Containers for fixed number of parts • JIT inventory: Minimum inventory (raw material, WIP and finished goods) to keep the system running • Tactics o Use a pull system to move inventory o Reduce lot size and setup time o Develop Just-in-Time delivery systems with suppliers o Use group technology 9/21/2015 29
- 31. Problems of keeping inventory Inventory Hides Problems Just as Water in a Lake Hides Rocks 9/21/2015 30 Unreliable supplier Setup time Late deliveries Quality problems Process downtime Scrap Setup time Late deliveries Quality problems Process downtime
- 32. Problems of keeping inventory 9/21/2015 31 Scrap Work in process inventory level (hides problems) Unreliable Vendors Capacity Imbalances Scrap Reducing inventory exposes problems so they can be solved. Unreliable Vendors Capacity Imbalances WIP
- 33. Quality improvement • JIT exposes quality problems by reducing inventory • JIT eliminates number defects with small lots • JIT requires quality by suppliers • Team approach and continuous improvement are important for ensuring quality • Quality is maintained by the following procedure: • Find the root cause of the problem, solve permanently and use team approach in solving the problems 9/21/2015 32
- 34. Quality improvement- Jidoka • Means “Automation with a human touch” • The word jidoka traces its roots to the invention of the automatic loom by Sakichi Toyoda, Founder of the Toyota Group • In 1896, Sakichi Toyoda invented Japan's first self-powered loom called the "Toyoda Power Loom” • Weft-breakage automatic stopping device -> automatically stopped the loom when a thread breakage was detected • a single operator could be put in charge of numerous looms -> tremendous improvement in productivity 9/21/2015 33
- 35. Jidoka- concept • Equipment stops when a problem arises • Operator can visually monitor and efficiently control many machines-> "visual control" or "problem visualization“ • Toyota plants use a problem display board system called "andon" • Andon allows operators to identify problems in the production line with only a glance 9/21/2015 34
- 36. Requirements for JIT 1. Stable production schedule 2. Small batch sizes and short set-up times 3. On time delivery 4. Defect free components and materials 5. Reliable production equipment 6. Pull system of production control 7. Capable, committed and co-operative work force 8. Dependable supplier base 9/21/2015 35
- 37. Comparison of JIT and Traditional Systems 9/21/2015 36 Factor Traditional JIT Inventory Much to offset forecast errors, late deliveries Minimal necessary to operate Deliveries Few, large Many, small Lot sizes Large Small Setup; runs Few, long runs Many, short runs Vendors Long-term relationships are unusual Partners Workers Necessary to do the work Assets
- 38. References 1. M. P. Groover, Automation, Production Systems, and Computer- integrated Manufacturing, 2009, 769-777 2. http://www.toyota.com.au/toyota/company/operations/toyota- production-system 9/21/2015 37
- 39. THANKS
Editor's Notes
- #3: Continuous flow manufacturing suggests a method in which work parts are processed and transported directly to the next work station one at a time. Each process is completed just before the next process in the sequence begins. This is jit with a batch size of unity. Production problems like late deliveries of componenrs, machine breakdowns, defective components
- #4: For example, to efficiently produce a large number of automobiles, which can consist of around 30,000 parts, it is necessary to create a detailed production plan that includes parts procurement. Write about the Toyota parts procurement and manufacturing Eliminates waste, inconsistencies, and unreasonable requirements, resulting in improved productivity. Inventory is a necessary evil