Jit and lean operations
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Just-in-time (JIT) production is a highly coordinated manufacturing system that produces goods and services just as they are needed. The ultimate goal of JIT is to achieve a smooth, rapid flow of materials through the production system with minimal inventories, waste, and transactions. Key elements of JIT include small lot sizes, continuous improvement, visual control systems like Kanban, and close supplier relationships. Benefits of JIT include reduced inventory levels, higher quality, flexibility, and increased productivity.
Jit and lean operations
- 1. JIT/Lean Production • Just-in-time (JIT): A highly coordinated processing system in which goods move through the system, and services are performed, just as they are needed • Highly Coordinated, Repetitive manufacturing designed to produce high volumes with fewer resources. • Developed by Taiichi Ohno
- 2. JIT Produce and deliver goods just in time to be sold, Subassemblies just in time to be assembled into FP and purchase material just in time to be transformed into fabricated parts. • A production system to produce the kind of units needed at the time needed and in the quantities needed. •
- 3. Goal of JIT The ultimate goal of JIT is a balanced system. Achieves a smooth, rapid flow of materials through the system Pursue a system with min. inventories, space, waste and min. transactions
- 4. Summary JIT Goals and Building Blocks Ultimate A Goal balanced rapid flow Supporting Goals Eliminate disruptions Make the system flexible Product Design Process Design Eliminate waste Personnel Elements Manufacturing Planning Building Blocks
- 5. Supporting Goals • Eliminate disruptions • Make system flexible • Eliminate waste, especially excess inventory
- 6. Sources of Waste • Overproduction • Waiting time • Unnecessary transportation • Processing waste • Inefficient work methods • Product defects
- 7. JIT Building Blocks • Product design • Process design • Personnel/organizational elements • Manufacturing planning and control
- 8. Product Design • Standard parts • Modular design • Highly capable production systems • Concurrent engineering
- 9. Process Design • Small lot sizes • Setup time reduction • Manufacturing cells • Limited work in process • Quality improvement • Production flexibility • Little inventory storage
- 10. Benefits of Small Lot Sizes Reduces inventory Less rework Less storage space Problems are more apparent Increases product flexibility Easier to balance operations
- 11. Production Flexibility • Reduce downtime by reducing changeover time • Use preventive maintenance to reduce breakdowns • Cross-train workers to help clear bottlenecks
- 12. Production Flexibility (cont’d) Use many small units of capacity • Use off-line buffers • Reserve capacity for important customers •
- 13. Quality Improvement • Autonomation • Automatic detection of defects during production
- 14. Personnel/Organizational Elements • Workers as assets • Cross-trained workers • Continuous improvement • Cost accounting • Leadership/project management
- 15. Manufacturing Planning and Control • Pull systems • Visual systems • Close vendor relationships • Reduced transaction processing • Preventive maintenance
- 17. Pull/Push Systems • Pull system: System for moving work where a workstation pulls output from the preceding station as needed. (e.g. Kanban) • Push system: System for moving work where output is pushed to the next station as it is completed
- 18. Kanban Production Control System • Kanban: Card or other device that communicates demand for work or materials from the preceding station • Kanban is the Japanese word meaning “signal” or “visible record” • Paperless production control system • Authority to pull, or produce comes from a downstream process.
- 20. Tiered Supplier Network Buyer Buyer First Tier Supplier Second Tier Supplier Third Tier Supplier Supplier Supplier Supplier Supplier Supplier Supplier Supplier Supplier Supplier Supplier Supplier Supplier Supplier Supplier
- 21. Comparison of JIT and Traditional 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
- 22. Transitioning to a JIT System • Get top management commitment • Decide which parts need most effort • Obtain support of workers • Start by trying to reduce setup times • Gradually convert operations • Convert suppliers to JIT • Prepare for obstacles
- 23. Obstacles to Conversion • Management may not be committed • Workers/management may not be cooperative • Suppliers may resist • Why?
- 24. JIT in Services The basic goal of the demand flow technology in the service organization is to provide optimum response to the customer with the highest quality service and lowest possible cost. Eliminate disruptions • Make system flexible • Reduce setup and lead times • Eliminate waste • Minimize WIP • Simplify the process •
- 26. Kaizen (Continuous Improvement) • • • • Japanese concept – Focus on gradual and continuous improvement A whole business philosophy Importance of EVERYONE buying into the concept and the vision
- 27. Kaizen Great attention paid to customer •Efficient stock control requirements and needs • methods help reduce costs and improve cash-flow •Flexible working practices and empowerment – help increase efficiency, reduce costs and improve •Leadership seen as vital. motivation Ability to communicate a clear vision, take people •Fundamental principles – along with the vision and often characterised as ‘lean to think about where the production’ – reducing waste, company needs to be in zero defects, high quality 5, 10, 15 and 20 yearsdelivery, •Punctuality in all aspects – control measures at all stages supply, time manufacture, etc.
- 28. 5 S of Kaizen Sort - the first step in making things cleaned up and organized • Set In Order - organize, identify and arrange everything in a work area • Shine - regular cleaning and maintenance • Standardize - make it easy to maintain simplify and standardize • Sustain -maintaining what has been accomplished •
- 29. Benefits of JIT Systems • Reduced inventory levels • High quality • Flexibility • Reduced lead times • Increased productivity
- 30. Benefits of JIT Systems (cont’d) • Increased equipment utilization • Reduced scrap and rework • Reduced space requirements • Pressure for good vendor relationships • Reduced need for indirect labor
- 31. Elements of JIT Smooth flow of work (the ultimate goal) • Elimination of waste • Continuous improvement • Eliminating anything that does not add value • Simple systems that are easy to manage • Use of product layouts to minimize moving materials and parts • Quality at the source •
- 32. Elements of JIT (cont’d) Poka-yoke – fail safe tools and methods • Preventative maintenance • Good housekeeping • Set-up time reduction • • Cross-trained employees • A pull system