How do they paint the stripes on resistors, bumble bee caps,

[MOP CAP]

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

 

On Tue, 12 Sep 2017 19:50:34 -0700, MOP CAP <email@domain.com> 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!!!!

 

[MOP CAP]

To measure the BV[ break down voltage] of a diode you apply a small
current [5 micro amp] and measure the voltage.
If it is a high voltage it is in one polarity. If a low voltage it is
the forward direction. If correct the diode drops down. If not it goes
thru a tube that rotates i it n the correction direction and into the
hopper for the painter..
CP

 

[Michael A. Terrell]

Taxed and Spent wrote:

On 9/9/2017 5:21 AM, Michael A. Terrell wrote:
oldschool@tubes.com wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Isn't it obvious? Early resistors were hand painted, then they
developed machines for the job.





how did they paint the machines?

They waited until they were completely built, you silly rabbit!


--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

[Michael A. Terrell]

oldschool@tubes.com wrote:

One thing I do know, is that most small electronic parts with wire
leads, leave the factory in the form of ladders. Meaning that 100 or
1000, or any other number of them are one long strip being held
together by 2 strips of paper around the leads, to form what looks
like a ladder.

Then you don't know anything.

So, if you worked at Zenith assembling radios, there would be rolls of
those ladders for every value of resistor, capacitor, etc, needed, at
each work station.

The proceed is called Tape + Reel, or Ammo Pac, but they are for
automated manufacturing. Leaded components are becoming rare, in
manufacturing, since Surface mount far exceeds leaded components, and
have for decades. Hand assembly doesn't use taped components, since it
takes time to remove the tape before a component is installed. Zenith
used odd tube sockets and terminal strips that often used the full
length of the component's leads. The tape's adhesive would cause cold
solder joints.

--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

 

[rickman]

oldschool@tubes.com wrote on 9/9/2017 2:14 PM:

I do believe the early resistors, especially those ceramic types that
had colored dots on them, were probably hand painted. I have also noted
that the old bumble bee caps often had irregular stripes, where the
paint was thicker in spots, thinner in others, and the edges were not
always precise.

Don't know about resistors being hand painted as that sounds expensive. But
I know mica caps used look hand painted and in searching I found one style
that is clearly hand painted.

--

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998

 

[Clive Arthur]

On 09/09/2017 03:11, oldschool@tubes.com wrote:

I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Resistors are made from a clay-like material containing carbon or other
conductor in various amounts. Colourants are added, and the material is
rolled and layered into large 'pats', so for example a 4k7 resistor pat
might have cream, yellow, cream, violet, cream, red, cream, gold, cream
coloured layers. This is rolled to the correct thickness corresponding
to the final resistor length, then hollow punches form the resistor
bodies, usually several thousand from one pat. The better quality ones
are rolled for smoothness and low noise. The wire ends are fitted, the
resistors are baked and often varnished. For high accuracy resistors,
the depth of one wire end is adjusted on test before the baking stage.

Cheers
--
Clive

 

[Terry Schwartz]

And I was under the delusion that the stripes were painted onto the resistors by tiny trained cockroaches wearing fashionable berets.

 

[pfjw@aol.com]

On Wednesday, January 3, 2018 at 1:28:00 PM UTC-5, Terry Schwartz wrote:
> And I was under the delusion that the stripes were painted onto the resistors by tiny trained cockroaches wearing fashionable berets.

https://pleatedjeans.files.wordpress.com/2010/08/cockroach-large.jpg

Not so fashionable.

Peter Wieck
Melrose Park, PA

 

[MOP CAP]

I explained once how stripes on DO-7 [about mid-way between a 1/4w and
1/2w resistors] diode bodies were painted.
You have paint troughs with the colors in use, each has a roller the
width of of the trough, against this you have a roller that tapers to
the width of the band. These in turn roll against a larger rubber wheel
and deposits the paint. This in turn rolls against the R or D.


On diodes the bands also indicated the polarity, so there was an
ingenious way to orientate them.
To measure the breakdown voltage of a diode you apply a small [5
micoamp current]. The diodes were fed into a slot, the current was
applied, if you measued a low voltage it dropped straight down.
If you measured a high voltage it went out the side into a tube that
brought it 180 deg. into the proper orientation.
CP

 

On Wednesday, 3 January 2018 16:11:52 UTC, Clive Arthur wrote:

On 09/09/2017 03:11, oldschool@tubes.com wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Resistors are made from a clay-like material containing carbon or other
conductor in various amounts. Colourants are added, and the material is
rolled and layered into large 'pats', so for example a 4k7 resistor pat
might have cream, yellow, cream, violet, cream, red, cream, gold, cream
coloured layers. This is rolled to the correct thickness corresponding
to the final resistor length, then hollow punches form the resistor
bodies, usually several thousand from one pat. The better quality ones
are rolled for smoothness and low noise. The wire ends are fitted, the
resistors are baked and often varnished. For high accuracy resistors,
the depth of one wire end is adjusted on test before the baking stage.

Cheers

You're surely pulling someone's leg.


NT

 

[Murray atuptown]

A lot of cookies that come from Elmhurst Illinois where Keebler used to be now say something to the effect of being partially made with genetic engineering. Famous Amos was apparently drawn into this conglomerate at an earlier date.

I no longer see mention of either the Keebler Elves or Amos when I see baked goods from Elmhurst nowadays. I’m sure they are all safe, but I still have this nagging image in my mind of an elderly Amos and elves who never age, caged in a laboratory, surrounded by people in white coars & safety glasses. Then I wake up and realize it was all a bad dream.

I think I know a guy who used to work for a resistor company. I’ll ask him (his name is mit Mr. Resistor) about the painting and hope he doesn’t tell me this quest is futile.

 

[Murray atuptown]

I just caught one of own touchscreen typos - I meant to say his name was NOT Mr. Resistor, but I typed mit.

Now I have to call him Mr. Resistor to protect my source.

He confirmed they did indeed use a striping machine that applied paint with some kind of brush as the component body was rotated. He said they also painted stripes helically on wire that was rotated to achieve the spiral path on the insulation and it then followed a path about 12 feet long vertically to give it time to dry.

I wonder if there is a carbon composition resistor mil-spec still out there on the internet that says anything more than requirements for color accuracy and durability.

 

[Murray atuptown]

Obsolete info, but you can download MIL-R11G from everyspec.com and look at paragraph 3.22. That will reference MIL-STD-1285, marking of electrical and electronic parts, also old info, but you have to start somewhere. Rev. B is the largest document so don’t look at the tiny later updates as they are missing the bulk of the details.

This will tell you very little other than that they aren’t supposed to be smeared and maybe standards for colors. You may find other references to pursue, but there are many other interesting things in there.

Or you become overwhelmingly bored and start to appreciate why the elves get grumpy, sleepy, dopey, etc.

If you pay for premium resistors you get numbers instead of colors.

 

[Jon Elson]

tabbypurr@gmail.com wrote:

On Wednesday, 3 January 2018 16:11:52 UTC, Clive Arthur wrote:
On 09/09/2017 03:11, oldschool@tubes.com wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Resistors are made from a clay-like material containing carbon or other
conductor in various amounts. Colourants are added, and the material is
rolled and layered into large 'pats', so for example a 4k7 resistor pat
might have cream, yellow, cream, violet, cream, red, cream, gold, cream
coloured layers. This is rolled to the correct thickness corresponding
to the final resistor length, then hollow punches form the resistor
bodies, usually several thousand from one pat. The better quality ones
are rolled for smoothness and low noise. The wire ends are fitted, the
resistors are baked and often varnished. For high accuracy resistors,
the depth of one wire end is adjusted on test before the baking stage.

Cheers

You're surely pulling someone's leg.

Oh yes, I'm sure of it! All the resistors I've used in the last 30 years or
so had a ceramic core, with ends fuest to the core, and then either metal
film or carbon film deposited onto that. Then, they use an air/abrasive
just to cut a helical groove in the film for higher resistance values.
Then, they are painted overall with that manufacturer's base color (often
tan or light blue) and then the color code is applied. I'm guessing they
have a machine with a row of some kind of rollers each with the right paint
color, and they paint all the stripes in one pass. But, I've never seen
pictures of such a machine.

If they were made as described above, the color would go all the way through
the resistor. I've broken enough over the years to know the inside is
always white for film resistors, and black for carbon composition.

Jon

 

On Thursday, 4 January 2018 22:14:06 UTC, Jon Elson wrote:

tabbypurr wrote:
On Wednesday, 3 January 2018 16:11:52 UTC, Clive Arthur wrote:
On 09/09/2017 03:11, oldschool@tubes.com wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Resistors are made from a clay-like material containing carbon or other
conductor in various amounts. Colourants are added, and the material is
rolled and layered into large 'pats', so for example a 4k7 resistor pat
might have cream, yellow, cream, violet, cream, red, cream, gold, cream
coloured layers. This is rolled to the correct thickness corresponding
to the final resistor length, then hollow punches form the resistor
bodies, usually several thousand from one pat. The better quality ones
are rolled for smoothness and low noise. The wire ends are fitted, the
resistors are baked and often varnished. For high accuracy resistors,
the depth of one wire end is adjusted on test before the baking stage.

Cheers

You're surely pulling someone's leg.
Oh yes, I'm sure of it! All the resistors I've used in the last 30 years or
so had a ceramic core, with ends fuest to the core, and then either metal
film or carbon film deposited onto that. Then, they use an air/abrasive
just to cut a helical groove in the film for higher resistance values.
Then, they are painted overall with that manufacturer's base color (often
tan or light blue) and then the color code is applied. I'm guessing they
have a machine with a row of some kind of rollers each with the right paint
color, and they paint all the stripes in one pass. But, I've never seen
pictures of such a machine.

If they were made as described above, the color would go all the way through
the resistor. I've broken enough over the years to know the inside is
always white for film resistors, and black for carbon composition.

Jon

Quite. Even in the carbon comp days they weren't made that way.


NT

 

[Murray atuptown]

The clay ones sound like the process used in the Lascaux process circa 15000 BC 🧐