Selected Solved Problems Chapter 8
This document delves into assembly line balancing principles, focusing on the calculation of cycle time (CT), efficiency, and total idle time for output management. Using the case study of producing 300 fishing reels per day with 6 workstations in a 7.5-hour workday, we derive CT using the formula CT = A/R, leading to a result of 1.5 minutes/reel. Additionally, assembly line efficiency is calculated at 88.9%, while total idle time is identified as 1 minute/reel. The content includes practical applications of balancing equations for effective work design.
Selected Solved Problems Chapter 8
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Selected Solved Problems Chapter 8 Facility and Work Design Collier/Evans OM3
Assembly-Line Balancing Cycle time (CT) is related to the output (R) by the following equation: CT = A/R [8.2] • A = available time to produce the output. • The output (R) is normally the demand forecast in units, adjusted for on-hand inventory if appropriate, or orders released to the factory. • Both A and R must have the same time units of measure (hour, day, week, month, and so on).
Bass Fishing Solved Problem (p. 155) Assembly line has six workstations. Management wants an output of 300 reels per day, (with a 7.5 hour workday). The sum of the task times is 8 minutes/reel. What is the cycle time? CT = A/R What is the assembly line efficiency? Efficiency = t/(N ×CT ) What is the total idle time? Total Idle Time = (N )(CT ) − t
Bass Fishing Solved Problem Assembly line has six workstations. Management wants an output of 300 reels per day, (with a 7.5 hour workday). The sum of the task times is 8 minutes/reel. What is the cycle time? CT = A/R = 1.5 min/reel What is the assembly line efficiency? Efficiency = t/(N ×CT ) = 88.9% What is the total idle time? Total Idle Time = (N )(CT ) − t = 1 min/reel
Assembly-Line Balancing Minimum number of workstations required = Sum of task times/Cycle time = t/CT [8.3] Total Time Available = (Number of work stations)×(Cycle Time) = (N )(CT ) [8.4] Total Idle Time = (N )(CT ) − t [8.5] Assembly-line Efficiency = t/(N ×CT ) [8.6] Balance Delay = 1 − Assembly-line Efficiency [8.7]
Exhibit 8.9 Precedence Network and Workstation Assignment Given: CT = 6.0 min/unit (see pages 156-157) WorkstationTasks Total TimeIdle Time A B Total
Exhibit 8.9 Precedence Network and Workstation Assignment WorkstationTasks Total TimeIdle Time A 1, 2, 5 5.7 0.3 B 3, 4, 6, 7, 8 3.7 2.3 Total 9.4 2.6
Assembly Line Balance for In-Line Skate WorkstationTasks Total TimeIdle Time A 1, 2, 5 5.7 0.3 B 3, 4, 6, 7, 8 3.7 2.3 Total 9.4 2.6 Using equations [8.4] to [8.6] we may compute the following: Total Time Available = (Number workstations)(Cycle Time) = (N )(CT ) = Total Idle Time = (N )(CT ) − t= Assembly-line Efficiency = t/(N ×CT ) =
Assembly Line Balance for In-Line Skate WorkstationTasks Total TimeIdle Time A 1, 2, 5 5.7 0.3 B 3, 4, 6, 7, 8 3.7 2.3 Total 9.4 2.6 Using equations [8.4] to [8.6] we may compute the following: Total Time Available = (Number workstations)(Cycle Time) = (N )(CT ) = (2)(6) = 12 minutes Total Idle Time = (N )(CT ) − t = (2)(6) - 9.4 = 2.6 minutes Assembly-line Efficiency = t/(N ×CT ) = 9.4/(2 × 6) = 78.3%
