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Operations Management Just-in-Time Systems. JIT/Lean Production. Just-in-time : Repetitive production system in which processing and movement of materials and goods occur just as they are needed, usually in small batches Is characteristic of lean production systems
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JIT/Lean Production Just-in-time: Repetitive production system in which processing and movement of materials and goods occur just as they are needed, usually in small batches • Is characteristic of lean production systems • Operates with very little “fat” • Is very responsive to customers
JIT vs. MRP II • Similar goals • Right products, right place, right time • MRP II • Computer-based, manages complexity • JIT • Manual systems, simplicity/execution • The Super Bowl of Planning & Control • Choice? - play to strengths
Just-In-Time Concepts • jit - Inventory/production control system • Supplies and components are ‘pulled’ through system to arrive where they are needed when they are needed. • JIT - Management philosophy of continuous improvement and forced problem solving
What Does Just-in-Time Do? • Multi-pronged approach • High quality, quick response, flexibility • Attacks waste • Anything not adding value to product (customer view) • Exposes problems and bottlenecks caused by variability • Deviation from optimum • Achieves streamlined production (pull system) • Reduced inventory • Simplified Execution
Waste 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 © 1995 Corel Corp.
Variability • Employees, machines, and suppliers produce units that do not conform to standards, are late, or are not the proper quantity • Engineering drawings or specifications are inaccurate • Production personnel try to produce before drawings or specifications are complete • Customer demands are unknown
Push versus Pull • Push system: material is pushed into downstream workstations regardless of whether resources are available • Pull system: material is pulled to a workstation just as it is needed
JIT Characteristics • A Fixed, Steady Rate of Production • Uniform flow/communicated to vendors • Mixed model, linear production • Low Inventories • Less space, investment • Uncover defects • Small Lot Sizes • Less WIP • Flexibility/Velocity • Fast feedback
JIT Characteristics • Quick, Low Cost Setups • Flexibility/Velocity • Small lot sizes • Layout • U-shaped • Cellular/flexible • Preventive Maintenance & Repair • Worker pride/ownership
JIT Characteristics • Empowered Workers • Multifunctional/Cooperative (Guerilla squad) • Flexible capacity • High Quality Levels • On-going production • Small/frequent deliveries • Product simplification • Standardization • Fewer part numbers/drawings
JIT Characteristics • Reliable Suppliers • Dock-to-stock • Much fewer in number • Long-term relationships • A Pull System of Moving Goods • Request-based • Kanban signal • Commitment to Problem Solving/ Continuous Improvement
Ultimate Goal A balanced rapid flow Supporting Goals Reduce setup and lead times Eliminate waste Minimize inventories Eliminate disruptions Make the system flexible Product Design Process Design Personnel Elements Manufactur-ing Planning JIT Building Blocks Building Blocks
JIT in Services All the techniques used in manufacturing are used in services Suppliers Layouts Inventory Scheduling
Converting to a JIT System • Top management commitment • Prioritize efforts • Worker support • Start by reducing setup times • Gradually convert operations • Convert suppliers to JIT • Prepare for obstacles
Obstacles to Conversion • Management not committed • Workers not cooperative • Suppliers may resist
JIT & Operations Planning and Control • MRP as planning tool • Level loading/linear production • Pull systems/visual control • Closer relationships w/ fewer vendors • Reduced transaction processing
Attributes of Lean Producers • use JIT to eliminate virtually all inventory • build systems to help employees produce a perfect part every time • reduce space requirements • develop close relationships with suppliers • educate suppliers • eliminate all but value-added activities • develop the workforce • make jobs more challenging • reduce the number of job classes and build worker flexibility