The following tasks are to be performed on an assembly line:
Explanation:
| TASK | SECONDS | TASKS THAT MUST PRECEDE |
| A | 18 | — |
| B | 12 | A |
| C | 10 | B |
| D | 14 | B |
| E | 26 | C |
| F | 28 | D |
| G | 15 | E-F |
| H | 15 | G |
| The workday is 8.75 hours long. Demand for completed product is 900 per day. |
| Required: | |
| (a) | Find the cycle time. (Round your answer to 1 decimal place.) |
| Cycle time | seconds per unit |
| (b) | What is the theoretical number of workstations? (Round your answer to the next whole number.) |
| Number of workstations |
| (c) | Balance the line using the longest-operating-time rule. (Leave no cells blank - be certain to enter "0" wherever required.Round your answers to 1 decimal place.) |
| Work station | Task | Idle time |
| I | A-B | |
| II | D-C | |
| III | F | |
| IV | E | |
| V | G-H | |
| (d) | What is the efficiency of the line balanced as in (c)? (Round your answer to 1 decimal place. Omit the "%" sign in your response.) |
| Efficiency | % |
| (e) | Suppose that demand rose from 900 to 1,000 units per day. What would you do? (Round your answer to the nearest whole number.) |
| Reduce cycle time to seconds, which may require rebalancing the line. |
| (f) | Suppose that demand rose from 900 to 1,100 units per day. What would you do? (Round your answer to the nearest whole number.) |
| Reduce cycle time to seconds, which may require rebalancing the line. |
Explanation:
(a):
(b):
(c):
Total task time T = 138
(d):
(e):
(f):
| C = production time per day/required output per day |
| C | = | Production Time Per day (in seconds) | = | 8.75*(60*60) | = | 35 seconds per unit |
| Required Output per day | 900 |
(b):
| Ni | = | T | = | 138 | = | 3.94 → 4 work stations |
| C | 35 |
(c):
| Work station | Task | Task time | Idle time |
| I | A-B | 18-12 | 5 |
| II | D-C | 14-10 | 11 |
| III | F | 28 | 7 |
| IV | E | 26 | 9 |
| V | G-H | 15-15 | 5 |
(d):
| Efficiency | = | T | = | 138 | = | 0.789 or 78.9% |
| NaC | 5(35) |
(e):
| Reduce cycle time to 32. New production level is (8.75 hours/day)(3600seconds per hour)/(32 seconds per unit) = 984 units per day. Therefore, they are 1,000 – 984 = 16 units short. Work (16units)(32 seconds per unit) = 512 seconds overtime. |
(f):
Reduce cycle time to 29. New production level is (8.75 hours/day)(3,600 seconds per hour)/(29 seconds per unit) = 1,086 units per day. |