Wip flow rate flow time example 6 schedule 1 send 2

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WIP = Flow rate * Flow time
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Example 6 - Schedule 1 Send 2 jobs every 8 min. One to M1, one to M2. Input rate = 15 units/hr (2/8) * 60 = 15 M 1 M 2 Bu M 3 Cycle time: 4 min / unit Output rate: 15 units/hr Average TPT: (9 + 13) / 2 = 11 min. WIP M1 M2 Bu M3 Total 5/8 = 0.625 5/8 = 0.625 4/8 = 0.500 8/8 = 1.000 2.750 Little’s Formula WIP = TPT / CT 2.75 = 11 / 4 M3 4 m M2 5 m M1 5 m Input rate = Capacity Mgmt 361 Chapter 2 - Process Analysis 18
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Assembly Operations Example 14 continued M1 9 min AA BB M2 5 min X1 3 min Y1 5 min P1 4 min R1 16 min R2 18 min R3 15 min Stage 1 Stage 2 Stage 4 Stage 3 Stage 5 Minimum TPT ? From Stage 1, you can get at the end of 5 minutes From Stages 2 and 3, you can get at the end of 8 minutes Both are required for the assembly. So you can start assembly after 8 minutes. Add 4 minutes on P1 then 15 minutes on R3. = 8 + 4 + 15 = 27 min AA BB Mgmt 361 Chapter 2 - Process Analysis 19
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Example 7 How much WIP? CT: Average TPT: WIP M1: M2: Buffer: M3: Total : 4 [min/unit] 1/3*(10+14+12)=12 [min] 10 / 12 = 5/6 units (10 min of work + 2 idle mins) 1 units (6/6) 2 / 12 = 1/6 units (2 min of buffer + 10 min empty) 1 unit (4/4) 3 units (5/6 + 1 +1/6 + 1 ) M1 M2 M3 Buffer 6 10 14 18 22 26 30 34 38 42 Idle time ignored in WIP calculations 5 4 4 5 6 6 6 2 1 1 2 3 3 3 8 7 7 8 9 9 9 Little’s Formula WIP = TPT / CT [ Q ] = [ T ] / [ T / Q ]. 3 = 12 / 4 [units] = [min] / [min / unit] Stage 1 Stage 2 M3 4 min M2 6 min M1 10 min Mgmt 361 Chap(ter 2 - Process Analysis 20 Run Time Parameters
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21 Assembly Line Balancing Line balancing: Assignment of work to stations in a line Goal: Efficiency, i.e. to achieve the desired output with a minimum number of workstations (= workers) and to find a balanced workload for the operators. Situation: Line set-up, rebalance or product/process changes
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