A manufacturing cell has SIX production stations operating in a close-coupled series arrangement on a production line. That is, Station 1 feeds Station 2, Station 2 feeds Station 3, Station 3 feeds Station 4, Station 4 feeds Station 5, while Station 5 feeds Station 6. There is no buffer stock between each Station. That means that if one station stops, the whole cell stops.
Historical data collection by maintenance and operating workers shows that the individual reliabilities of each station (i.e. the probability that, at any point in time, that station will be running) are as follows:
• Station 1: 98.3%
• Station 2: 91.0%
• Station 3: 94.1%
• Station 4: 92.0%
• Station 5: 88.0%
• Station 6: 93.0%
What is the probability that, at any point in time, the whole line will be stopped? Clearly show your working and cite any sources you may use.
• For the cell described in Part 2, the total potentially available working time in one week is 6 days at 15 hours per day. The average expected useable output is 45 perfect parts per hour. In reality, the actual total output (when the line is actually running) is one part every 2½ minutes, of which 12 parts per 7½-hour shift are not useable because of irreparable defects.
Based on the foregoing cell data, determine the following:
• The equipment availability, in %, for the whole cell
• The cell's total actual working time per week (in minutes, hours or hours & minutes)
• The planned production output at full speed and 100% yield
• The cell yield
• The OEE for the whole cell.
Show your working clearly, and use a spreadsheet if it helps.
• A process engineer advises that a duplicate station be installed in Station 5, in parallel with the original one. What might be the effect(s) of this change?