31 4 stations c kilbridge wester method to solve line

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= 3.1 4 stations . (c) Kilbridge & Wester method to solve line balancing problem ( TT s = 60 min): List of elements by column Allocation of elements to workstations Element TT k Column Station Element TT k TT si 1 21.5 min I 1 1 21.5 min 3 31.9 min II 3 31.9 min 53.4 min 2 12.9 min II 2 2 12.9 min 5 53.4 min III 4 10.0 min 4 10.0 min III 6 7.2 min 30.1 min 6 7.2 min III 3 5 53.4 min 53.4 min 7 15.0 min IV 4 7 15.0 min 8 12.6 min IV 8 12.6 min 9 21.5 min V 9 21.5 min 49.1 min 186.0 min 186.0 min 114
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Assembly Lines-3e-S 07-05/06, 06/04/07 (d) Maximum{ TT si } = 53.4 min E b = 186 0 4 534 . ( . ) = 0.871 = 87.1% 15.25 For the data given in previous Problem 15.24, solve the mixed model line balancing problem except use the ranked positional weights method to determine the order of entry of work elements. Solution : (a) and (b) Same solution as Problem 15.24 (a) and (b). (c) Ranked positional weights method to solve line balancing problem ( TT s = 60 min): Element RPW A RPW B Σ ( RPW ) Station Element TT k TT si 1 105.0 81.0 186.0 1 1 21.5 min 3 75.0 66.6 141.6 3 31.9 min 53.4 min 2 75.0 50.4 125.4 2 2 12.9 min 5 57.5 45.0 102.5 4 10.0 min 4 37.5 - 37.5 6 7.2 min 30.1 min 6 - 28.8 28.8 3 5 53.4 min 53.4 min 7 27.5 - 27.5 4 7 15.0 min 8 - 21.6 21.6 8 12.6 min 9 12.5 9.0 21.5 9 21.5 min 49.1 min 186.0 min (d) Maximum{ TT si } = 53.4 min E b = 186 0 4 534 . ( . ) = 0.871 = 87.1% 15.26 Three models A, B, and C are to be assembled on a mixed model line. Hourly production rates for the three models are: A, 15 units/hr; B, 10 units/hr; and C, 5 units/hr. The work elements, element times, and precedence requirements are given in the table below. Assume E = 1.0, E r = 1.0, and M i = 1. (a) Construct the precedence diagram for each model and for all three models combined into one diagram. (b) Find the theoretical minimum number of workstations required to achieve the required production rate. (c) Use the Kilbridge and Wester method to solve the line balancing problem. (d) Determine the balance efficiency for the solution in (c). Element T eAk Preceded by T eBk Preceded by T eCk Preceded by 1 0.6 min - 0.6 min - 0.6 min - 2 0.5 min 1 0.5 min 1 0.5 min 1 3 0.9 min 1 0.9 min 1 0.9 min 1 4 - 0.5 min 1 - 5 - - 0.6 min 1 6 0.7 min 2 0.7 min 2 0.7 min 2 7 1.3 min 3 1.3 min 3 1.3 min 3 8 - 0.9 min 4 - 9 - - 1.2 min 5 10 0.8 min 6, 7 0.8 min 6, 7, 8 0.8 min 6, 7, 9 T wc 4.8 min 6.2 min 6.6 min Solution : (a) Precedence diagrams: 1 2 3 6 7 10 0.6 0.5 0.7 0.9 1.3 0.8 Model A: 15 units/hr 115
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Assembly Lines-3e-S 07-05/06, 06/04/07 1 2 3 4 6 7 8 10 0.6 0.5 0.9 0.5 0.7 1.3 0.9 0.8 Model B: 10 units/hr 1 2 3 6 7 10 0.6 0.5 0.9 0.7 1.3 0.8 Model C: 5 units/hr 5 9 0.6 1.2 1 2 3 4 6 7 8 10 Combined: A + B + C 5 9 ABC ABC ABC ABC ABC ABC B C B C (b) Given M = 1, E = 1, E r = 1, and therefore, AT = 60 min, n = w = Minimum Integer 15 4 8 10 6 2 5 6 6 60 ( . ) ( . ) ( . ) + + = 2.78 3 workstations and 3 workers (c) Computation of workload: Element k R pA T eAk R pB T eBk R pC T eCk Σ R pj T ejk 1 9.0 min 6.0 min 3.0 min 18.0 min 2 7.5 min 5.0 min 2.5 min 15.0 min 3 13.5 min 9.0 min 4.5 min 27.0 min 4 - 5.0 min - 5.0 min 5 - - 3.0 min 3.0 min 6 10.5 min 7.0 min 3.5 min 21.0 min 7 19.5 min 13.0 min 6.5 min 39.0 min 8 - 9.0 min - 9.0 min 9 - 6.0 min 6.0 min 10 12.0 min 8.0 min 4.0 min 24.0 min 167.0 min Line balancing solution using Kilbridge & Wester method: List of elements by column Allocation of elements to workstations 116
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Assembly Lines-3e-S 07-05/06, 06/04/07 Element TT k Column Station Element TT k TT si 1 18 min I 1 1 18 min 3 27 min II 3 27 min 2 15 min II 2 15 min 60 min 5 5 min II 2 4 5 min 4 3 min II 5 3 min 7 39 min III 7 39 min 6 21 min
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  • Spring '10
  • Hani
  • Chemical element, Cycle Time, Production line

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