Presentation on theme: "1 Just-in-Time/Lean Production A repetitive production system in which the processing and movement of materials and goods occur just as they are needed!"— Presentation transcript:
1 Just-in-Time/Lean Production A repetitive production system in which the processing and movement of materials and goods occur just as they are needed!
2 Pre-JIT: Traditional Mass Production
3 Post-JIT: “Lean Production” Tighter coordination along the supply chain Goods are pulled along — only make and ship what is needed
4 JIT Goals (throughout the supply chain) Eliminate disruptions Make the system flexible Reduce setup times and lead times Minimize inventory Eliminate waste
5 Waste Definition: 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 President, Toyota
6 Forms of Waste: Overproduction Waiting time Transportation Processing Inventory Motion Product Defects
7 Inventory as a Waste Requires more storage space Requires tracking and counting Increases movement activity Hides yield, scrap, and rework problems Increases risk of loss from theft, damage, obsolescence
8 Building Blocks of JIT Product design Standard parts Modular design Quality Process design Personnel and organizational elements Manufacturing planning and control
9 Process Design “Focused Factories” Group Technology Simplified layouts with little storage space Jidoka and Poka-Yoke Minimum setups
10 Personnel and Organizational Elements Workers as assets Cross-trained workers Greater responsibility at lower levels Leaders as facilitators, not order givers
11 Classic Organizational View
12 JIT Organization View
13 Planning and Control Systems “Small” JIT Stable and level schedules –Mixed Model Scheduling “Push” versus “Pull” –Kanban Systems
14 Kanban Uses simple visual signals to control production Examples: empty slot in hamburger chute empty space on floor kanban card
15 Kanban Example Workcenter B uses parts produced by Workcenter A How can we control the flow of materials so that B always has parts and A doesn’t overproduce?
16 When a container is opened by Workcenter B, its kanban card is removed and sent back to Workcenter A. This is a signal to Workcenter A to produce another box of parts. Kanban card: Signal to produce
17 Empty Box: Signal to pull Empty box sent back. Signal to pull another full box into Workcenter B. Question: How many kanban cards here? Why?
18 How Many Kanbans? y = number of kanban cards D = demand per unit of time T = lead time C = container capacity X = fudge factor
19 Example Hourly demand = 300 units Lead time = 3 hours Each container holds 300 units Assuming no variation in lead-time or demand (x = 0): y = (300 3) / 300 = 3 kanban cards
20 Extending the pull system
21 Note: For a kanban system to work, we NEED CONSISTENT demand across the work centers How do we ensure this?
22 Mixed Model Sequencing Largest integer that divides evenly into daily requirement is 10: A: 40 / 10 = 4 B: 40 / 10 = 4 C: 10 / 10 = 1 Mixed model sequence: A-B-A-B-A-B-A-B-C ProductMonthly Demand Daily Requirement A80040 B80040 C20010