Wheeled Coach , the world’s largest manufacturer of ambulances, is the kind of firm you would want to take your students to tour to see how factories work. The firm uses 5 parallel assembly lines, fed by work cells, in which 5 ambulances move forward to the next work station each day. The work cells feed the main assembly lines on a JIT basis and perform all the pre-assembly work, such as painting, carpentry, upholstery, electrical wiring , etc.
When I show the video (7 min.) in class, I simultaneously draw the 5 parallel lines, and label in each day’s work station as it is described. You can discuss how the work cells are more efficient than having the tasks they perform done as part of the line.
Some interesting aspects are not shown. First, these are real factory jobs, often dirty, non-union, low paying, and all hot! (There is no A/C –or heat– in most factories here in Florida). So staffing is usually difficult (this recession being an exception, of course).
When we filmed, workers did 5 standard 8-hours shifts, starting 6:30am. When hiring was really tough, Wheeled Coach switched to four 10-hour days to make the job more attractive. That made line balancing even more difficult, since each vehicle still needed to move forward once a day. It took a few years before the firm realized this only made matters worse, as quality fell dramatically in the last 2-3 hours of the shift. It returned to the 5 day week recently.
How else could efficiency improve? Last time I visited, the smaller “van conversion” models were moved to a different building on their own line, with 3 or 4 flowing off every day, since they are much simpler designs.