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!!!!
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
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! ;-)
Then you don't know anything.
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! ;-)
snipped-for-privacy@tubes.com wrote on 9/9/2017 2:14 PM:
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
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
And I was under the delusion that the stripes were painted onto the resistors by tiny trained cockroaches wearing fashionable berets.
Not so fashionable.
Peter Wieck Melrose Park, PA
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
You're surely pulling someone's leg.
NT
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 engine ering. Famous Amos was apparently drawn into this conglomerate at an earlie r date.
I no longer see mention of either the Keebler Elves or Amos when I see bake d goods from Elmhurst nowadays. I?m sure they are all safe, but I s till have this nagging image in my mind of an elderly Amos and elves who ne ver age, caged in a laboratory, surrounded by people in white coars & safet y 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.
I just caught one of own touchscreen typos - I meant to say his name was NO T 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 pa inted 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 verticall y 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 accura cy and durability.
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 an d 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 reference s to pursue, but there are many other interesting things in there.
Or you become overwhelmingly bored and start to appreciate why the elves ge t grumpy, sleepy, dopey, etc.
If you pay for premium resistors you get numbers instead of colors.
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
The clay ones sound like the process used in the Lascaux process circa 1500
0 BC ?ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.