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[email protected] oldschool@tubes.com is offline
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Default How do they paint the stripes on resistors, bumble bee caps, etc?

On Tue, 12 Sep 2017 19:50:34 -0700, MOP CAP wrote:

It has been over 50 years since I worked at the Fairchild diode plant.
Our diodes were in the DO-7 packagen and most were striped marked. I
can't remember the fine details of the machine that was used as I was
not directly involved. The diodes were fed on to an approx 3" diameter
with notched on the circumference every, 30 or so degrees. Before that
there was an ingenious device that oriented them for polarity. The
marking was to be towards the cathode end. There were 3 or 4 wheels
that tapered to the width of the intended line. Each of these wheels
ran nto a paint pot with the appropriate color. The diode rotated in
the notch on the 3" wheel and against the paint wheel, went one ot two
notched past for a semi fast dry and fell into a bin. Sorry I don't
have a better memory.
CP


That makes sense and the wheels would rotate the diode, resistor, etc. I
did assume the paint was very fast drying. How they managed to get the
correct polarity with that device is hard to imagine. I can only guess
there was a means to get a meter reading on them in mass amounts.
Interesting stuff!!!!