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?
They get the christmas elves in the off season to paint them on with their toy decorating brushes.
No, but after an hour or so hunting through my father's random box of hundreds of resistors looking for the value I wanted, I got a powerful urge to take any old one and paint on the right colours... (Never did, though!)
Mike.
We could tell you, but then we'd have to kill you. Legal mumbo jumbo out of the way, would you like me to explain it to you?
Isn't it obvious? Early resistors were hand painted, then they developed machines for the job.
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how did they paint the machines?
Angelfish caps (Mullard) were dipped in paint to different depths to form the stripes.
Cheers
Phil Hobbs
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Carefully.
It's a no brainer they use a machine. My question goes much deeper. How does the machine do it? Are the paints applied by a paint brush, or something like a felt tip marker, or maybe some sort of spray method? Once the correct colors are chosen for that batch of (whatever value), how do they rotate them so the paint is not smeared. I can only assume they are picked up by their leads, not the body, and somehow rotated by their leads too.
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.
There is a series on tv, which is usually only shown on Saturday mornings, during the kids shows, that show how an item is made. The ones I remember are making candy, and making lightbulbs (incandescent). They show the entire process, start to finish, and show each step both in the machines and how workers are involved. I cant recall the name of them programs, and have not seen any in a long time, but they are quite interesting. That lightbulb one was extremely interesting. Each bulb is tested in a machine and workers watch ot make sure they light up. Seeing this, (on tv or youtube), for resistors would be interesting. Too bad they dont have more stuff like that on tv, rather than the usual garbage that is mostly on the channels these days.
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.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.
By the way, there is a good documentary video on youtube that shows radios being made at Zenith. It was filmed in (If I recall correctly), the 1950s. Worth watching!
You really think a spray would be a good match for this app?
seriously?
good luck in life.
We live in a world that can print an M on a small candy, print tens of thou sands of devices on a bit of epoxy, and make geared watches with gears (whe els) with pitches measured in microns - and has been doing this in the case of watches for nearly 200 years, and in the case of electronics for well o ver 60 years. Then, consider the printing technology required for paper mon ey.
So, printing stripes and other markings on devices the size of even an 1/8- watt resistors would be a simple issue.
I would posit a rotating intaglio printer as a relatively simple device wit h very prices application ability and little slop. And although the print h eads would wear, they would have very nearly infinite life as compared to a brush or roller. This is the purest speculation, of course.
Peter Wieck Melrose Park, PA
Intaglio requires very heavy pressures of around 80T/square inch generated by *very* heavy machinery; much, much heavier than litho or letterpress which are like balsa toys by comparison. Then you have to have the right plates. Engraving those plates to an acceptable standard requires very *considerable* expertise by people who can command pay grades that elevate them *way* above every other 'manual' worker into a league of their own.
It certainly is. You are right about the simplicity of the machinery, though.
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I remember when computers used core memory the manufacturers employed oriental women to string the cores because of their small, nimble hands. This may be much the same kind of thing.
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It does when printing on paper. However, not when printing on solid materia ls such as glass bottles as a primary example. That requires a fast-cure (u sually heat), high-tack ink, and quite light pressure given the speeds invo lved. Consider the typical direct-printed beer-bottle.
Peter Wieck Melrose Park, PA
Not any more. They now have to use a proportional share of big, hairy, burly men. They throw those misprinted resistors out. Haven't you noticed the price increases?
May I humbly suggest you reconsider your speculation. Intaglio is slow. It works well for flat objects but not so well with irregular diameters, such as metal film resistors: Notice the irregular diameter and inconsistent bulges at the ends cause by dipping and turning the resistor (before marking) in some kind of insulating coating before firing. Dealing with these inconsistencies and irregularities probably eliminates any form of ink tranfer that involved physical contract with the resistor body such as roller, brushes, stamping, etc. My guess(tm) is some kind of ink jet or spray marker applied while spinning the resistor around its center line. I haven't found any machinery yet that claims to do this.
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That's not true. There are no such things as elves. Only faries. ERS
Then who the hell makes the cookies?
Trolls make the cookies, but only the "Troll House" brand. :)
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
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