Batch & Queue vs Lean Continuous Flow
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The document compares and contrasts continuous flow and batch production methods. Continuous flow focuses on eliminating waste such as waiting time, excess inventory, and defects through one-piece flow and small batch sizes. This allows for faster cycle times, increased throughput and capacity, and reduced lead times compared to batch production which typically has longer cycle times and more non-value added time due to large batch sizes and waiting between processes. The document provides examples of value stream maps to illustrate the differences between batch and continuous flow production systems.
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Batch & Queue vs Lean Continuous Flow
- 1. Continuous Flow vs Batch Production January 12, 2019 by Julian Kalac, P.Eng Lean Six Sigma Master Black Belt 1
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- 3. 3 Shipped on time and customer happy We Made $$$$ ProductionMaterial Ship order CUSTOMER • No Wasted Time • No Wasted Money • No Wasted Resources • No Wasted Material ? ? 99% Customer Quality
- 4. The truth 4 The Hidden Factory $50000-material scrap costs $350,000 transportation costs Lost order Wrong order shipped ProductionMaterial Ship order CUSTOMER Hidden Factory
- 5. The systematic elimination of waste and re-alignment of resources to deliver value to the customer faster, better, & more consistently Lean also is: ◦ Pursuit of excellence ◦ Continuous Improvement of performance and quality ◦ . ◦ Increasing inventory “turns” and throughput ◦ Simplifying and redefining processes ◦ Measuring & monitoring processes ◦ Empowering the workforce (80%) Leading to Leading to Eliminate Waste Reduced Cycle Times Increased Capacity Focus: Eliminate waste, non-value add steps, process constraints and bottle necks that cause problems in work
- 7. Value Added Typically 95% of all lead time is non-value added 1. Overproduction 2. Waiting 3. Transportation 4. Non-Value Added Processing 5. Excess Inventory/Material 6. Defects 7. Excess Motion 8. Underutilized People Non-Value Added 5%
- 8. | | 8 Lack of cross-functional training Over relying on a select few while others are Inadequately trained Operators are unable to rotate and help each other out to balance the work-load High overtime, increased pressure stress
- 9. Workers can do each others work, help out when someone is sick, on holidays, quit Workers help improve bottleneck operations by helping out each other Variety in work making it more full-filling Training new workers
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- 12. Cycle Time is dictated by the slowest (bottleneck) operation in the cell. 40 min 20 min 25 min 15 min 30 min 1 54 3 2 •What operation controls the cycle? •How can you relieve the bottleneck?
- 13. Bottleneck ◦ The point which is currently reducing the flow or slowing the entire process ◦ A managed buffer before a bottleneck is necessary ◦ A bottleneck WILL exist in every process ◦ Bottlenecks move ! ◦ High WIP can mask the bottleneck ◦ The people working at the bottleneck take breaks, not the bottleneckSource: Improve Phase 26jul07
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- 19. FABRICATION BATCH VSM –Total Cycle Time= 9.1 days Customer Complaint Total Cycle Time = 9 days Value Added Time = 14 min 1 people C/T = 2 min C/O = 3 hr Uptime = 71% Inspection 2 people CNC 1 C/T = 4 min C/O = 2 hr Uptime = 64% 2 people C/T = 10 min C/O = 4 hr Uptime = 28% WELD 2 QC Late Delivery 5 min1 min1 min 2 days 3 day2 days 1 days Production Order WK D Wk 6 WEEKS INVENTORY DELIVERED EVERY SHIPMENT TO SAVE ON TRANSPORTATION COSTS C/T = 12 min C/O = 30 min Uptime = 83% 175T PRESS 1 days 0 Customer BSupplier 1 Supplier 2 3 weeks lead time WIP WIP VA Time NVA Time I 30% REWORK 14% SCRAP I
- 20. 3x Week Market Forecast Total Cycle Time = 4.1 hrs Value Added Time = 7 min Customer A Customer B 1 people C/T = 2 min C/O = 20 min Uptime = 88% CNC 2 1 people CNC 1 C/T = 4 min C/O = 0.5 hr Uptime = 78% 1 people C/T = 3 min C/O = 30 min Uptime = 67% ROBOT WELD 1 people Shipping Production Control Supplier 1 Supplier 2 C/T = 2 min C/O = 30 min Uptime = 93% PRESS D I 3 min2 min2 min 1 hr 1 hr1 hr1 Hr 2 min INVENTORY TURN- OVER RATE NVA Time VA Time 1 Piece Flow and continuos feedback loop 1 % SCRAP
- 21. BATCH vs LEAN 1 PCS CONTINUOUS FLOW BATCH LEAN Pcs CRIMPING PULL TESTING FINAL ASSY PACKING Sec/Pc CRIMPING PULL TESTING FINAL ASSY PACKING Sec/Pc SETUP TIME (SEC) 300 5 5 0 310 300 5 5 0 310 1 10 14 8 10 1 10 14 8 10 42.0 2 10 14 8 10 2 10 14 8 10 14.0 3 10 14 8 10 3 10 14 8 10 14.0 4 10 14 8 10 4 10 14 8 10 14.0 5 10 14 8 10 5 10 14 8 10 14.0 6 10 14 8 10 6 10 14 8 10 14.0 7 10 14 8 10 7 10 14 8 10 14.0 8 10 14 8 10 8 10 14 8 10 14.0 9 10 14 8 10 9 10 14 8 10 14.0 10 10 14 8 10 10 10 14 8 10 14.0 400 145 85 100 10 478 + + + 1040 Totsl Cycle Time 10Pcs (sec) 478 478 17 Cycle Time 10pcs (min) 7.97 42 1030 First Part Packed (sec) 42 7.97 1040 Last Part packed (sec) 478 104 Avg cycle time /Pc (sec) 47.8 104sec/p 47sec/pc
- 22. CURRENT STATE EATS VSM Customer Demand Total Non-Value Add Time = 4.5 days Value Added Time = 173 min (2.8Hrs) 2 operator C/T = 34 min C/O = 0.5 hr Uptime = 61% Joining & Inspection 2 operator Tacking C/T = 52 min C/O = 0.5 hr Uptime = 86% 1 operator C/T = 47 min C/O = 0 hr Uptime = 78% Manual Weld 1 QC+ 1 welders 8 sets/day 47 min34 min52 min 1 day 2 day1 day 0.5 days Production Order WK D Wk INVENTORY C/T = 40 min C/O = 0 min Uptime = 83% Robot Weld 40 Customer BLaser Break Press WIP WIP VA Time NVA Time I REWORK Batch & Que Production
- 23. 3x Week Market Forecast Total Non-Value Add Time = 1.5 days Value Added Time = 114 min ~2 Hrs Customer A Customer B 0.5 operator C/T = 44 min C/O = 5 min Uptime = 70% 0.5 operator Tacking C/T = 30 min C/O = 0.5 hr Uptime = 85% 1 QC+ 1 welders C/T = 40 min C/O = 0 min Uptime = 95% Joining & Inspection 12 sets/day Production Control Laser Break Press Robot 7 D 40 min44 min30 min 0.5 days 1 days0 days INVENTORY TURN- OVER RATE NVA Time VA Time 1 Pc continuous flow
- 24. 30 min 20 min25 min 25 min 30 min 1 54 3 2 •What is the process cycle time? •What is the process bottleneck? New Cycle Time = 30min
- 25. Get All Your Needed Material Before You Start! Set-up equipment as close as possible together so you can pass parts without using boxes Eliminate WIP BOXES Set-up a white board and record hourly PPMH compared to target. List any issues you have during the run Run 1 order at a time in the cell until it’s completed and then next order 2
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