UnitManufacturingProcessesAssembly and Joining2.008 Manufacturing Systems i 2 Outline 2.008 - Spr ng 2004 1. Manufacturing Systems 2. Types of Plant Layouts 3. Production Rates 4. Design and Operations Manufacture Manufacturing Research Factory, ••••••••Stamping •Conceptual Manufacture i 4 What is mfg systems? Unit Processes Assembly and Joining Market Systems & Enterprise Welding Bolting Bonding Soldering Machining Injection molding Casting Chemical Vapor Deposition Design Design for 2.008 - Spr ng 2004 i 5 Manufacturing Organization .1 1 101 102 103 104 105 106 107 108 ityPeriPl i i l ilill iiiling / lly l l lli il i 6 How Man, Machine, and Material Spend Time in the Factory Val -Val -Val -i ls, i ii lookii iing ii iti ii ii ii2.008 - Spr ng 2004 Time spectrum of Typical Activities in a Millisecond .001 .01 Second Minute Hour Day Month Week Year Decade Activod Seconds ant des gn, Mach ne Se ect on, System Simu ation Process des gn: CAD Cata ogs Se ect manufactur ng methods Factory Operat on Sh p – Receive Transport Inventory Part handLoad Un oad AssembMachine controCNC – DNC Adaptive controInte gent mach nes Process contro2.008 - Spr ng 2004 Waste u e adde d Waste ue adde d Waste ue adde d People Materials Machines “Waste”: wait ng for materiawatching mach ne runn ng, produc ng defects, ng for tools, fix ng mach ne breakdowns, producunnecessary tems, etc. “Waste”: transportation, storage, nspect on and rework “Waste”: unnecessary movement of machine, setup me, mach ne breakdown, unproduct ve ma ntenance, produc ng defect ve products, produc ng products when not needed, etc. 1Types of Plant LayoutDisruptions/Variation (Random Events) • Job Shop • Machine failure • Project Shop • Set-up change • Flow Line • Operator absence • Transfer Line • Starvation/Blockage • Cellular System • Demand change 2.008 - Spring 2004 7 2.008 - Spring 2004 8 Job Shop Project Shop AA AA DD DD DD CC CC CC Ready part Raw Material Machines/Resoues Machines/Resources are brought to and are grouped according removed from to the process they stationary part as perform B B required C D D D A A material/ Raw Ready part 2.008 - Spring 2004 9 2.008 - Spring 2004 10 Flow Line and Transfer Line Cellular System B D A F D A F C G B F Ready part Raw Material Machines/Resources Machines/Resources are grouped are grouped in lines according to the according to the processes required processes sequence for part families of part(s) CB ED ED GF BA FD Ready part Raw Material 2.008 - Spring 2004 11 2.008 - Spring 2004 12 2i 13 1 100 iji 14 Production Rates • iM 1 = 2.008 - Spr ng 2004 Production Quantity and Plant Layout 10 1,000 10,000 100,000 Flow L ne C ellular Syste m Job Shop Pro ect Shop Quantity 2.008 - Spr ng 2004 Case I: – One machine – Everyth ng works time Operation rate Production i 15 Production Rates (cont’d) • Efficiency MTTR MTTF MTTRMTTF MTTFEfficiency = = + = M i 16 Production Rates (cont’d) • M1 M2 Mi Mk 2.008 - Spr ng 2004 Case II: – One machine – Machine breaks down (disruption) – Everything else works time Operation rate Production on)(utilizati 2.008 - Spr ng 2004 Case III: – Many machines – No machine breaks down – No buffers i 17 Production Rates (cont’d) • M1 M2 Mi Mk i 18 Production Rates (cont’d) • M1 M2 Mi Mk 2.008 - Spr ng 2004 Case IV: – Many machines (same operation time) – No machine breaks down – No buffers 2.008 - Spr ng 2004 Case V: – Many machines (same operation time) – Machine breaks down – No buffers 3i 19 Production Rates (cont’d) • M3M1 M2B1 B2 MkMBk-1 2.008 - Spr ng 2004 Case VI: – Many machines and buffers in between – Machine breaks down k-1 Production Rates (cont’d) • Production rate increases if: – Increase the rate of the slowest machine – Reduce the disruptions – Introduce “buffers” – Introduce in-process control 2.008 - Spring 2004 20 Disruptions (Random Events) • Machine failure • Set-up change • Operator absence • Starvation/Blockage 2.008 - Spring 2004 21 Waiting • Underutilization • Idleness • Inventory 2.008 - Spring 2004 22 Inventory/Work-in-Process (WIP) • It costs money • It gets damaged • It becomes obsolete • It shrinks • It increases lead time 2.008 - Spring 2004 23 i 24 Cycle Time and Lead Time Plant Order Order Supplier = 2.008 - Spr ng 2004 Supply Supply Customer demand average Daily time available Daily time Takt 4Cycle Time Cycle Time (cont’d) “Cycle Time” •Example: Operation time = 1, One-piece operation • The time a part spends in the system Little’s Law: L = λw L: average inventory Cycle time = 5 iM1 M2 M3 M5M4 Product on rate = 1 λ: average production rate Inventory = 5 w: average cycle time 2.008 - Spring 2004 25 2.008 - Spring 2004 26 Cycle Time Cycle Time Batch Production One-Piece Production 1. Op1 Op2 Op3 2. Op1 Op2 Op3 Operation time: 3 minutes Operation time = 3 minutes Batch (Lot) size: 1000 Cycle time = 1,000*3 + 1,000*3 + 1,000*3 = 9,000min Cycle time = 1,000*3 + 2*3 = 3,006 minutes 2.008 - Spring 2004 27 2.008 - Spring 2004 28 i 29 Cycle Time and Lead Time Plant Order Order Supplier = 2.008 - Spr ng 2004 Supply Supply Customer demand average Daily time available Daily time Takt Systems Design and Operation • Cycle time < Lead time • Lumpiness • Information contents 2.008 - Spring 2004 30 5Lumpy Demand Wrench A Wrench B Wrench C Wrench D 5 151515P 666666D 1010P 333333D 2525P 777777D 252525P 200015020D 5050P 00350035D iil Z 5 P 1 1 1 1 1 1 D Forg ng X Forg ng Y SteeD 75 0 25 50 0 25 2.008 - Spring 2004 31 Typical Design Guidelines • Leveling • Balancing • Single-piece flow • Low materials handling • Low setup time • Smaller lot size •Low WIP • Faster feedback 2.008 - Spring 2004 32 Plant Operations • Push (MRP, ERP, etc.) vs. Pull (JIT) • Batch vs. One-piece 2.008 - Spring 2004 33