Factory%20Planning L5

Day 60 minhr x 60 secmin 60 secunit desired output

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Unformatted text preview: 0 sec/min 60 sec./unit desired output units/hr 60 units/hr – Limited by the bottleneck task (the longest task in a process): Maximum output available time 3600 sec./hr. 72 units/hr,or pizzas per hour bottleneck task time 50 sec./unit 7 4/29/2011 Layout Calculations (continued) • Step 4: Compute the theoretical minimum number of stations – TM = number of stations needed to achieve 100% efficiency (every second is used) TM task times cycle time 165 seconds 2.75, or 3 stations 60 sec/station – Always round up (no partial workstations) – Serves as a lower bound for our analysis Layout Calculations • (continued) Step 5: Assign tasks to workstations – Start at the first station & choose the longest eligible task following precedence relationships – Continue adding the longest eligible task that fits without going over the desired cycle time – When no additional tasks can be added within the desired cycle time, begin assigning tasks to the next workstation until finished Workstation 1 2 3 Eligible task A B C D E, F, G E, F F H I Task Selected A B C D G E F H I Task time 50 5 25 15 15 12 10 18 15 Idle time 10 5 35 20 5 48 38 20 5 8 4/29/2011 Last Layout Calculation • Step 6: Compute efficiency and balance delay – Efficiency (%) is the ratio of total productive time divided by total time Efficiency (%) t NC 165 sec. 100 91.7% 3 stations x 60 sec. – Balance delay (%) is the amount by which the line falls short of 100% Balance delay 100% 91.7% 8.3% Assembly-Line Balancing Objective is to minimize the imbalance between machines or personnel while meeting required output Starts with the precedence relationships 1. Determine cycle time 2. Calculate theoretical minimum number of w orkstations 3. Balance the line by assigning specific tasks to workstations 9 4/29/2011 Copier Example Perform ance Time Task (minutes) A 10 B 11 C 5 D 4 E 12 F 3 G 7 H 11 I 3 Total time 66 Task Must Follow Task Listed Below — A B B A C, D F E G, H This means that tasks B and E cannot be done until task A has been completed Copier Example Perform ance Time Task (minutes) A 10 B 11 C 5 D 4 E 12 F 3 G 7 H 11 I 3 Total time 66 Task Must Follow Task Listed Below — A B B A C, D F 10 E A G, H 5 11 C 7 F B 3 G 4 12 E D 3 11 I H Figure 9.13 10 4/29/2011 Copier Example Perform anc...
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This note was uploaded on 12/29/2012 for the course ISE 543 taught by Professor Araby during the Spring '12 term at MSA University.

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