Thursday, December 8, 2011

A Supply Chain Puzzle

While I was listening to Car Talk on NPR this past weekend, I couldn't help but notice that the previous week's "puzzler" was supply chain relevant (as you may know, this is not always the case). As it is the end of the semester, I thought it might be a good opportunity to put everything we've learned so far together, and also kind of fun to try to solve this supply chain case study.

The story goes like this: in the late 60s/early 70s, Ford released a new car model. It was fairly well-received, but like any new car model there were some initial 'bugs' that people discovered, and there was one problem in particular that the good people at Ford could not figure out. Dealerships were reporting that exactly one out of every six cars they received from the factory arrived with a dead battery.

Ford's engineers tested the wiring in the cars for faults, but couldn't find anything. They spoke with the battery supplier, and tested incoming batteries to see if one in 6 were faulty, but again: the batteries themselves were fine.

So Ford hired outside consultants and experts who ran tests on the different things... even the interaction of chemicals used in this particular model, but none of the outside people could pinpoint exactly what was wrong. For three months the mathematical equation held: the dealership could expect exactly one of every six cars to arrive with a dead battery.

Finally, a quality control engineer went to the factory that produced this particular car model and walked the entire line, talking to workers at every single stage of assembly. He followed a number of cars all the way to the Final Testing area, and every single car assembled would start up just fine and be driven to the holding lot.

Finally, "He... explained to the tester the situation and asked him if he could think of a reason why one out of six batteries were always dead on this particular model. The guy stared off into the distance. He pondered. He scratched his butt. And then he smiled, and he said he knew EXACTLY what the problem was."

Since we are all supply chain experts at this point, what was the problem? (Hint: This was the old days, when cars were big.)

For the answer, highlight the hidden text below.


Here's the answer: As I mentioned, at this time, American cars were BIG. And the trucks that carried the cars could only carry SIX cars. As a result, one of the cars was always at such an angle that the mercury switch for the trunk light (which was the standard at the time) was turning the trunk light on the entire time the car was being was transported, which drained the battery.


So, given what we've learned this semester, what elements of supply chain management were successful in resolving this problem? Ford was able to learn from this mistake, but what lesson could be applied to future problems?

You can listen to the problem here, and the answer here. Or, if you're really adventurous, listen to the whole show here. (note: the answer is not revealed in that show.)

1 comment:

  1. hah, i thought the problem might have been in the transit process, but i didn't realize that the flow of the mercury within the trunk light could've been responsible.


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