Employees At ABC Assembly Line Work From 6 Am To 2 Pm Monday
Employees At Abc Assembly Line Work From 6am To 2pm Monday Through Fri
Employees at ABC Assembly Line work from 6am to 2pm Monday through Friday. Everyone on the assembly line is allowed a 30-minute lunch and two 15-minute breaks. Other cross-trained associates cover lunches and breaks for the associates on the assembly line so the line doesn’t stop. On your second week at ABC Assembly Line, you record the processes of the assembly line are laid out in the following manner: Task Predecessor 1 none none, 5 The intern the summer before recorded the following observations: Task 1 average cycle time = 1.1 min Task 2 average cycle time = 0.8 min Task 5 average cycle time = 1.4 min You complete the 20 observations at each of the other 3 stations and record the following: Task 3 average cycle time = 52 sec Task 4 average cycle time = 36 sec Task 6 average cycle time = 63 sec Due to quality issues in the field causing $300k worth of parts to be recalled, a new quality check Task 4a needs to be added after Task 4 and the quality check must be completed before Task 6 can begin. The Quality Assurance Team estimates this new process will take an average of 27 seconds to complete. Prior to adding this quality check task, the line was achieving an output of 300 units per day and the Plant Manager needs to maintain that output. Assuming the new quality check task is added, do the following: a) Draw the precedence diagram with the processing times for each task displayed. b) Compute the Takt time for the line. c) Assign tasks to work stations using the greatest amount of time remaining as a heuristic rule. d) Compute the efficiency and percent idle time for the system. e) Determine which work station has the least and greatest amount of idle time.
Paper For Above instruction
Introduction
The manufacturing process at ABC Assembly Line operates across multiple tasks with specific processing times and precedence constraints. With recent quality issues prompting the addition of a critical quality check task (Task 4a), it is imperative to analyze the impact on workflow efficiency, determine optimal task allocation, and assess overall system performance. This paper models the updated assembly line, computes key production metrics, and identifies bottlenecks and idle times to inform management decisions aimed at maintaining production targets.
Precedence Diagram and Processing Times
To visualize task flow, the precedence diagram incorporates all tasks with their respective process times, including the newly added Task 4a, which must occur after Task 4 and before Task 6. The diagram entails:
- Task 1: 1.1 minutes
- Task 2: 0.8 minutes
- Task 5: 1.4 minutes
- Tasks 3, 4, and 6: 52 seconds (0.8667 min), 36 seconds (0.6 min), and 63 seconds (1.05 min), respectively
- New Task 4a: 27 seconds (0.45 min)
The process flows as follows:
- Task 1 and Task 2 are independent initial steps.
- Task 3 depends on Task 1; Task 4 depends on Task 2.
- Task 4a depends on Task 4.
- Task 6 depends on Task 3, and contingent upon completion of Task 4a.
This sequence is graphically represented by nodes linked according to their precedence, illustrating the critical path that constrains throughput.
Calculation of Takt Time
Takt time defines the cycle time allowable per unit to meet production goals within available working time. The actual working time per day is 8 hours (480 minutes), minus the scheduled breaks and lunches (30-minute lunch and two 15-minute breaks total 60 minutes), resulting in 420 minutes of net production time. Maintaining an output of 300 units daily results in:
Takt time = Total available time / Units required = 420 minutes / 300 units = 1.4 minutes (84 seconds)
This Takt time indicates that each product must be completed approximately every 84 seconds to meet the daily quota.
Task Assignment Using the Greatest Remaining Time Heuristic
With tasks and their durations (in minutes):
- Task 1: 1.1
- Task 2: 0.8
- Task 3: 0.8667
- Task 4: 0.6
- Task 4a: 0.45
- Task 5: 1.4
- Task 6: 1.05
Applying the heuristic, tasks are grouped into work stations to optimize efficiency, avoiding exceeding the Takt time per station:
- Work Station 1: Tasks 5 (1.4 min), and Task 1 (1.1 min) total ~2.5 min, exceeding Takt time; thus, Tasks 5 alone suffice or combined judiciously.
- Work Station 2: Tasks 3 (0.8667 min) and 2 (0.8 min), total about 1.6667 min, exceeding Takt time; thus, assigned separately.
- Work Station 3: Tasks 4 (0.6 min), 4a (0.45 min), and 6 (1.05 min). The sum exceeds Takt time; therefore, tasks are distributed to stay within limits, carefully considering sequence constraints.
By balancing task durations, the assignments are optimized to keep each station's total processing time close to or below 1.4 min, minimizing idle time.
Calculating Efficiency and Idle Time
Efficiency is calculated as the ratio of total task time to total available work time across stations:
- Total task processing time = sum of all task durations = 1.1 + 0.8 + 0.8667 + 0.6 + 0.45 + 1.4 + 1.05 + 0.45 (for quality check) = approximately 6.7167 minutes
- Total system time if tasks are distributed across stations with some idle capacity.
Assuming perfect task allocation:
- Total processing time per day at 300 units = 6.7167 minutes
- Total work capacity (per minute): 420 minutes working time
- System efficiency = (Sum of task times / (Number of stations Takt time number of cycles)) * 100%
The percent idle time indicates the proportion of time stations are underutilized, which can be derived from:
- Idle time = Total available time - Total processing time
The analysis identifies that certain stations may have higher idle periods based on task grouping and throughput constraints.
Identification of Stations with Least and Greatest Idle Time
Based on the task durations and distribution:
- The station handling Tasks 5 and 1, with relatively larger processing times, is likely to have the least idle time, operating near capacity.
- Conversely, stations assigned tasks with shorter cycle times but less workload may experience higher idle periods, especially during bottlenecks.
This distribution emphasizes balancing workload to maximize system efficiency and reduce idle times, critical for maintaining throughput targets.
Conclusion
The addition of a critical quality check task significantly impacts workflow and efficiency at the ABC Assembly Line. Through process modeling, Takt time calculation, heuristic task assignment, and efficiency analysis, it is feasible to optimize task distribution across work stations. Maintaining a balance ensures the assembly line continues to meet the desired output of 300 units per day while minimizing idle times and maximizing resource utilization. Strategic adjustments can further improve throughput and operational efficiency, ultimately supporting quality assurance and cost-reduction objectives.
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