The difference between Six Sigma projects and
A toothpaste factory had a
problem: they sometimes shipped empty boxes, without the tube inside. This was
due to the way the production line was set up, and people with experience in
designing production lines will tell you how difficult it is to have everything
happen with timing so precise that every single unit coming out of it is
perfect 100% of the time.
Small variations in the
environment (which can’t be controlled in a cost-effective fashion) mean you
must have quality assurance checks smartly distributed across the line so that
customers all the way down to the supermarket don’t get ticked-off and buy
another product instead.
important that was, the CEO of the toothpaste factory got the top people in the
company together and they decided to start a new Six Sigma project, in which
they would use their black belt team to solve their empty boxes problem, as
their engineering department was already too stretched to take on any extra
The project followed the
usual process: budget and project sponsor allocated, RFP, third-parties
selected, and six months (and $8 million) later they had a fantastic solution -
on time, on budget, high quality and everyone in the project had a great time.
They solved the problem by using high-tech precision scales that would sound a
bell and flash lights whenever a toothpaste box would weigh less than it
should. The line would stop, and someone had to walk over and yank the
defective box out of it, pressing another button when done to re-start the line.
later, the CEO decides to have a look at the ROI of the project: amazing
results! No empty boxes ever shipped out of the factory after the scales were
put in place. Very few customer complaints, and they were gaining market share.
“That’s some money well spent!” – he says, before looking closely at the other
statistics in the report.
turns out, the number of defects picked up by the scales was 0, after three
weeks of production use. It should’ve been picking up at least a dozen a day,
so maybe there was something wrong with the report. He launched an
investigation, and after some work, the black belts come back saying
the report was actually correct. The scales really weren't picking up any
defects, because all boxes that got to that point in the conveyor belt were
A few feet before the
scale, there was a $20 desk fan, blowing any empty boxes off of the belt and
into a recycling bin. “Oh, that,” says one of the workers - “one of the
guys put it there ’cause he was trained in lean thinking and walking over
to clear and reset the line every time the bell rang was a "waste"
(motion, excessive processing, defects and rework). We've even started a
mistake proofing Kaizen team to eliminate the real root cause of the
problem - the packaging machine process!
Puzzled, the CEO traveled
down to the factory, and walked up to the part of the line where the precision
scales were installed.