Have you ever wonder how defroster windows work? Electrical current is applied to a heater pattern built right into the window. The electrical current heats up the strips that are typically configured as a set of thin dark lines made with metallic ceramic ink that has just the right resistance to heat up.
But how do you
attach wires from the window to the vehicle's electrical system? The ink is
made with enough metal powder to allow wire or metal connectors to be soldered
day the solder supplier got a call that something was wrong and they were
breaking thousands of dollars' worth of windows every day. What could be going
Solder was applied to the connector tabs by dipping them into a molten
solder bath and there wasn't much that could go wrong with that process.
there a change in the solder alloy? If the alloy changed, the assemblers might
turn up the soldering iron settings or press harder when the solder doesn't
melt within a few seconds.
But the soldering tools were not running hot and the
solder alloy was right on target, so solder was not the culprit. But the auto
manufacturer was sure that the solder was involved in some indirect way and
time the solder vendor went out to visit the plant, the yield went up
dramatically and hardly any windows broke. But while the vendor was away,
broken windows set new records.
Most everyone decided that it still had
something to do with overheating of the glass, and maybe the workers were just
extra careful when being watched.
they tested a technique using conductive adhesive. The following week, samples
were brought in and tests were started. The adhesive was more expensive than
solder since it contained mostly silver power while the solder was made from
tin and lead.
vendor argued that the new process would cut labor costs and the higher
materials cost was inconsequential. The vendor continued to make a case for
this labor-saving breakthrough and pointed out that broker windows would drop
of the workers, who was on break, was fascinated by the new technology since it
looked like solder that soldered itself. So he asked questions until he had a
good idea how it all worked.
He also recognized that he could be replaced since
this process, if it worked, would need less than half as much labor as the old
soldering iron method.
following week, the yields went to 100% for the old soldering process. This
wasn't a fluke because the same thing happened during the following week, and
again on the 3rd week. So what's was going on?
the rest of the story.
engineer solved the mystery. The workers had a grievance that wasn't being
handled too their liking, but it wasn't worth a strike. So they were cranking
up the soldering irons and breaking windows. It may sound dumb, but this
happened in the days when companies and workers acted like they hated each
what fixed the problem? Once the line workers realized that conductive adhesive
would fix the problem and probably get rid of a few workers, they
decided to bring stop to their destructive tactics.