Homework 6a Operations

Justin Prater Chapter 6A 3, 4, 9, and 14 3) a. b. Cycle time = production time per day/required output per day = [(8 hour/day)(3600 seconds/hour)]/240 units per day = 120 seconds per unit c. Work station| Task| Task time| Idle time| I| AD| 6050| 10| II| BC| 8020| 20| III| EF| 9030| 0| IV| GH| 3060| 30| d. Efficiency = Task time / [# stations X avg. cycle time) = = . 875 or 87. 5% 4) a. A B F C D E G 30 35 15 65 H 30 35 40 25 A B F C D E G 30 35 15 65 H 30 35 40 25 b. What is the workstation cycle time? Cycle time = production time per day/required output per day Cycle time = 27000 / 360 = 75 seconds. . Calculate this balance line using the largest number of following tasks. Use the longest task time as a secondary criterion. 275 / 75 = 3. 66 There should be a minimum of 4 work stations Work station| Task| Task time| Idle time| I| ACE| 303015| 0| II| BD| 3535| 5| III| F| 65| 10| IV| GH| 4025| 10| d. What is the efficiency of your balance line? 91. 7% 9. A B F C D E G 20 7 15 10 H 20 2 2 16 8 A B F C D E G 20 7 15 10 H 20 22 16 8 a. Cycle time = production time per day/required output per day Cycle time = 25200 / 750 = 33. 6 seconds. b. What is the theoretical number of workstations? workstations = sum of task times / cycle time 118 / 34 = 3. 5 There is a minimum number of 4 workstations. c. Draw the precedence diagram d. Balance the line using sequential restrictions and the longest-operating time rule. Work station| Task| Task time| Idle time| Feasible Rem. T. | Tasks w/ most foll| Task w/ longest t. | | I| AB| 207| 147| B| B| B| | II| DF| 2210| 122| F| F| F| | III| C| 20| 14| | | | | IV| EG| 1516| 193| G| G| G| | V| H| 8| 26| | | | | e. What is the efficiency of the line balanced as in d? Efficiency = Sum of task times / (# workstations X Cycle time) = 118 / (5 X 34) = . 70Efficiency = 70% f. Suppose that demand rose from 750 to 800 units per day. What would you do? Show any amounts or calculations. New cycle time = 25200/800 = 31. 2 seconds Reduce cycle time t o 31 seconds and work 62-3 minute overtimes. g. Suppose that demand rose from 750 to 1000 units per day. What would you do? Show any amounts or calculations. New cycle time = 25200/1000 = 25. 2 seconds 1. 89 hours overtime; may be better to rebalance. 14) Develop two alternative layouts. What is the efficiency of your layouts? A B F C D E G 1 1 3 1 H 2 1 1 2 1 I A B F C D E G 1 1 3 1 H 2 1 1 2 1 I Cycle time = 4 minutesWhat is the theoretical number of workstations? # workstations = sum of task times / cycle time 13 / 4 = 3. 25 Work station| Task| Task time| Idle time| Feasible Rem. T. | Tasks w/ most foll| Task w/ longest t. | | I| ABC| 11 2 | 32 0| B,F C,D| B C,D | B,F C| | IIIIIIV| DEFGHI| 131121| 303203| EGH| EGH| EGH| | Work station| Task| Task time| Idle time| Feasible Rem. T. | Tasks w/ most foll| Task w/ longest t. | | I| AFG| 11 1 | 32 1| B,F G| B G | B,F G| | IIIIIIV| BCDEHI| 311321| 313021| C,DEI| C,DEI| C,DEI| |