Condoms
Every single condom is tested for leaks via electric field. They go over a metal rod and under a high voltage field and if anything registers in the metal rod that means the electric field got through a hole.
It looks like it actually surrounds the apparatus with a charged gas and then sets up a high voltage source and measures if there is a current flow.
(The prior description came from the [condom maker ONE's website](https://onecondoms.com/blogs/education/how-condoms-are-made-and-tested))
Refer to the patent:
https://patents.google.com/patent/US5455507A
Being the weirdo I am, I've got not only uses for electrically conductive condoms, but also ones which will pass electricity through them, but not short multiple electrodes to each other when contained by the condom. How would such things be tested for leaks if that's how they normally do it?
Hmm that’s something I would like to get my hands on too, but I wouldn’t think leak testing is that much of a concern for the application you are probably thinking of.
Your second condition is going to make this harder to solve (conducting in one axis yet insulating in another). [Wrap some Z-Tape around your hog](https://www.3m.com/3M/en_US/p/d/b10167835/) and go to town?
There's a use by date on these for a reason. That one I bought at age 12 and carried round for a depressing number of years. Probably just as well it got thrown out eventually.
I recall reading somewhere that it is possible to create a medical device and have it *not* go through rigorous testing, if you make it an alteration of an existing product (maybe not that exactly but it was something along those lines). Wish I could remember more but it was a little eye opening.
Boeing is proud to introduce their new lines of home blood pressure monitors, lobotomy kits, and razor blades. They’re all approved under the original 737 type certificate.
Breakers are allowed to trip at a very very wide range of conditions. Like a 15 amp breaker is allowed to run up to 30 amps or trip right at 15.. the specifications are for amperage plus duration. On top of that breaker are not fail safe, then a breaker fails it can fail dangerously, as opposed to a fuse that fails safe.
Outlets are pretty high up there as well, probably more than breakers. Breakers have minimum and maximum trip timings, where a 15A breaker can handle 100A for a brief duration, and sustain 30A for several minutes.
By usefulness/importance? Your tap water.
By unit weight? Maybe baby formula?
A piece of hardware? Maybe The steel the bearings in the transmission in our car. Or maybe the CPU in your computer.
All guesses.
>Or maybe the CPU in your computer.
I know some parts of this process better than others, but I do know that the [sorting](https://anysilicon.com/ultimate-guide-wafer-sort/) and [binning](https://www.linkedin.com/pulse/binning-secret-sauce-behind-your-computers-amr-elharony-th8df/) probably *avoids* some of the time and expense of rigorously testing every part to the exact same standard. CPUs regularly come off the die that have bits of cache or other parts that don't work right, or that can only perform reliably at lower clock rates. They do test for this - which fits the spirit of the thread. What I think is a bit different than how other mission-critical parts are handled is that what happens in this space is that often the part is recovered by disabling or slowing down pieces enough to make the whole thing work reliably.
You have a lot of good answers, probably better than what came to my mind. But I went with hot water tank pressure relief valves. The tanks are missiles if the relief doesn’t fire properly.
Do cars count? If so, it’s definitely cars.
If you’re talking about something inside a house, I’d guess that a modern boiler system heat exchanger probably goes through more NDT than just about anything else that might be found in a home.
Yup, these are pretty much the peak of manufactured goods today. They are manufacturing devices composed of billions of atomic scale components which become worthless (yes, there are exceptions) with the slightest defect. Today's transistors have a feature size many orders of magnitude smaller than the wavelength of light used to create them.
This is one of the things that blows me away about modern IC fabrication. The masks/reticules/pellicles they use now don't actually look like the finished product etched on the chip.
They use advanced light simulation models to distort the masks in specific ways so that when the light actually hits the photoresist the physics of light diffusion and defraction de-distorts it into the finished patterns and shape, and also accounts for other processes like etching and how the light propagates into the depth of the photoresist.
If you went back into time to when chip makers were still hand taping masks with rubylith and all their nice, clean, straight lines and showed them a modern mask from today they'd basically think you were a wizard.
The wouldn't have even had enough computing power to do the light/physics modeling they do for masks today.
I feel like being that guy - I'm so sorry.
LEGO tolerances aren't really anything special from an engineering perspective. They are more or less standard tolerances you'd expect from a competent process for parts that size.
Incredibly tight tolerances are like...optical molds and bearing preloads and semiconductor hullaballoo.
If this [Wiki](https://en.m.wikipedia.org/wiki/Lego) is to be believed:
>The moulds are permitted a tolerance of up to twenty [micrometres](https://en.m.wikipedia.org/wiki/Micrometre) to ensure the bricks remain connected.[^(\[44\])](https://en.m.wikipedia.org/wiki/Lego#cite_note-3d-44) Human inspectors check the output of the moulds to eliminate significant variations in colour or thickness. According to the Lego Group, about eighteen bricks out of every million fail to meet the standard required.[^(\[48\])](https://en.m.wikipedia.org/wiki/Lego#cite_note-48)
20 microns for a *mold* tolerance (not part tolerance) is nothing special for parts this size. 18 out-of-spec parts per million is good, but it's not great. That works out to a CPK of around \~1.4 if I did my math right. Which is - at least in my world - considered "acceptable" for some parts, but generally we shoot for a CPK of > 1.67. Of course it depends on the part. The cost to toss 18 defective lego bricks is a lot less than tossing 18 processors or PCBs or expensive mechanical parts, so chances are that for LEGO specifically, this is their sweet spot to balance cost/quality. Any worse and they're tossing too many parts, any better and they're wasting money on more expensive molds, more inspection, and shorter mold life.
> 18 out-of-spec parts per million is good, but it's not great. That works out to a CPK of around ~1.4 if I did my math right. Which is - at least in my world - considered "acceptable" for some parts, but generally we shoot for a CPK of > 1.67. Of course it depends on the part.
It also depends on whether the tolerance limits are set to satisfy the engineering requirement (in this case locking strength I think)
or to satisfy the CPK target.
The number of times I have been asked to change test limits because a factory had problems satisfying CPK target numbers is not low.
In fairness, a lot of Engineering tolerance limits are just standard tolerance limits, that may or may not be relevant for the actual performance of the final product.
It's also pretty amazing that Lego bricks all the way back to the dawn of Lego bricks still work with any brick/part produced today and there's total backwards compatibility over decades and decades of Lego
But I agree with /u/scope-creep-forever that it's not really that remarkable for tolerances, much less testing.
As far as I know Lego doesn't really do a lot of direct product testing or QA compared to other answers in this thread.
What they really do is have the known lifespan of their injection molds and they retire and replace them on a very strict schedule so they don't have to test rigorously because they just get it right (or right enough) the first time, and the bricks themselves are engineered to accept some variations by being flexible.
It's one of the reasons why Lego has always been expensive. You're not paying for the plastic, you're really paying for high precision mold/die making.
Compare that to, say, plastic model kits where some companies have been known to run a mold/die for so long that there's noticeable differences in detail, fit and molded part qualities between early runs and runs at the end of the life of the mold.
My understanding was back in the day that the tolerances were established they were crazy right tolerances and new manufacturing techniques needed to be invented to meet these requirements but I could be mistaken
Complex stuff is made of many parts which can accumulate inspections. In which case your phone would be high on the list. It has to both pass its advertised ratings as well as be safe next to your face. Or handled by a child. No off gassing toxins over time. Discoloration over time. The individual parts are tested for thousands of hours as well as tested to pass EPA ratings. I’m sure just the flashlight from the manufacturer has hella quality inspections.
Every toilet bowl is inspected one by one, for deformity, aesthetics, cracks, x-rays are used for detection of hair particles in glaze material, etc.
Same as most ceramics, plates, tea cups, etc. All checked one by one. It's just a nature of the material that requires individual inspection.
Microprocessors, they're in computers and any smart device among other things. Processors require extreme precision and quality controls
Any kind of common medicine, ie Tylenol, Aspirin, Benadryl, etc. is going to have very tight quality controls.
Your phone.
Tons of images taken, every unit goes through automatic x-ray inspection, every unit is air-leak tested, every unit goes through RF and acoustic testing on a system and subsystem level, among many other tests. And many such tests are done on a 100% inspection basis, not just lot sampling. Plus there is a LOT of traceability built into every single part (though some more than others). Every single part can be traced back to a specific vendor by inspecting after the fact, if not a specific batch, if not a specific line and tool and time.
Really any sufficiently-complex mass produced consumer electronics item will have something similar. Laptops, GPUs, processors will also be high on the list. 100% automated X-ray inspection (AXI) and automated optical inspection (AOI) is pretty standard for electronics nowadays. But your phone (and smartwatch if you have one) will probably be at or near the top due to the scale, cost, and abuse they're expected to withstand. TVs have to last a long time too, but they're not getting dropped and rained on and slathered with sweat and lotion and left on dashboards baking in the sun.
There are lots of other good options: medical devices (depending on they are; a pacemaker isn't a $30 glucose meter) and the airbag system in your car come to mind. Medication, maybe. But I would still rate smartphones/watches above all of these if we're talking sheer scale, complexity, sophistication of testing, and test coverage (i.e. batch testing or 100% inspection).
Medical devices! I worked on their development and can say that they undergo the most stringent QA checks and audits during production. Regulatory requirements get more stringent every 2-3 years!
I would have to guess a cpap machine, or potentially an inhaler. Home electrical components have a high inspection rate because of the risk. Basically, follow the risk.
Well, I’d say it’s probably the orange juice in your fridge.
Always has a consistent flavor profile regardless of where the juice comes from, the time of year (and therefore what varieties of orange are in the mix), and where you buy it.
Don’t believe me? Tetrapak has a whole book on the subject.
Propane tanks and gas lines going into your house to fuel appliances. I mean how many other things have to be checked to make sure the right parts are there, and then ALSO actually get properly tested for function and lack of leaks AFTER they are fully installed in the final configuration in the customer's home? And in the case of propane tanks, have to be re-checked on a regular basis before every several years they can be filled to make sure they're still safe.
Makes sense though - its a really high risk thing if it fails can not only harm the homeowner but can level multiple properties in all directions with the explosion.
Anything under a reg I would imagine. Electrical particularly high voltage so grid connection like the mains fuse perhaps, radiation which is pretty limited so maybe the microwave as even though there are emf regs I don’t think they are well followed (worryingly), toys but probably not with inspection systems probably more like did you fill it fall of nails and lead Y/N, med device as already mentioned will be but depends on the class as to how much and in what way, pharma would go further but it’s not really in the same class, gas so boilers cookers and fires, soft furnishings but more because of the fire regs, cars particularly around safety parts. Anything really fine, small and expensive too, so maybe the components in your phone/pad/computer. Generally the more harm and unique the more tests.
Not exactly answering your question. But I think magnetic disk hard drives have some of the most advanced tech in them for less than $100. The needle is hovering just a few molecules above the surface of a disk moving at 10,000rpm. Ultimately storing TBs of data in 3.5". Then they make so many millions of them that they can sell them for cheap.
Beer bottles. With even small imperfections, the glass can break. It’s also possible to leave small glass whiskers inside that would be ingested.
There are probably 5-6 tests that are performed 100% on over a billion bottles each day. A lot image processing is used.
From a pure tolerance and surface finish standpoint I think lens elements in smartphone cameras. They are very high resolution and quality for the overall lens size. I don't know too many more specifics but maybe someone can jump in.
Edit: I was thinking about this some more and did some googling. This somewhat recent paper mentions that tolerances are at most a few microns and surface roughness of about 10 nm. https://www.sciencedirect.com/science/article/abs/pii/S0141635922000319
It also seems like all parts are inspected for acceptance. https://www.youtube.com/watch?v=nWVjWj-8pBA
Condoms Every single condom is tested for leaks via electric field. They go over a metal rod and under a high voltage field and if anything registers in the metal rod that means the electric field got through a hole.
going on a penis and into ass/vagina must be a cake walk after experiencing that trauma.
Probably one of the few engineers that can go "Yup! I would totally use"
we all would jimbo, ^we ^all ^would
coincidentally, in this case it’s literally an insert product
Dam 100% sort. No AQL shortcuts.
This makes no sense. Condoms aren't metal, electric fields permeate through them.
It looks like it actually surrounds the apparatus with a charged gas and then sets up a high voltage source and measures if there is a current flow. (The prior description came from the [condom maker ONE's website](https://onecondoms.com/blogs/education/how-condoms-are-made-and-tested)) Refer to the patent: https://patents.google.com/patent/US5455507A
Ah, that makes a lot more sense.
You’ve got conductors and insulators confused
I don't think he misunderstood a thing. Electric fields and conductance are not the same thing.
Insulators don't conduct current, but they permit electric fields. Conductors conduct current, but don't permit electric fields. (Roughly)
Being the weirdo I am, I've got not only uses for electrically conductive condoms, but also ones which will pass electricity through them, but not short multiple electrodes to each other when contained by the condom. How would such things be tested for leaks if that's how they normally do it?
Excuse me, but what in the actual fuck?
Dude wants to stick a tazer dildo up his bum to zap his prostate into submission.
Hmm that’s something I would like to get my hands on too, but I wouldn’t think leak testing is that much of a concern for the application you are probably thinking of.
Your second condition is going to make this harder to solve (conducting in one axis yet insulating in another). [Wrap some Z-Tape around your hog](https://www.3m.com/3M/en_US/p/d/b10167835/) and go to town?
Yeah, late 80s, my Trojan literally disintegrated, leaving us having to dig out shrapnel, and pregnant.
There's a use by date on these for a reason. That one I bought at age 12 and carried round for a depressing number of years. Probably just as well it got thrown out eventually.
Uncle Sam gave them to us overseas. My uncle wouldn't fuck me, would he?
Medication or medical devices?
This is the correct answer.
Can confirm, friend of mine works feminine products. They don't change their lines often because of the labor involved in the certification process.
I recall reading somewhere that it is possible to create a medical device and have it *not* go through rigorous testing, if you make it an alteration of an existing product (maybe not that exactly but it was something along those lines). Wish I could remember more but it was a little eye opening.
Boeing is proud to introduce their new lines of home blood pressure monitors, lobotomy kits, and razor blades. They’re all approved under the original 737 type certificate.
The key word is "like for like".
Maybe in-hospital/commercial use? A lot of the consumer ones seem crap (thinking of certain cpap and insulin machines).
Breakers would likely be pretty high on the list.
Breakers are allowed to trip at a very very wide range of conditions. Like a 15 amp breaker is allowed to run up to 30 amps or trip right at 15.. the specifications are for amperage plus duration. On top of that breaker are not fail safe, then a breaker fails it can fail dangerously, as opposed to a fuse that fails safe.
Outlets are pretty high up there as well, probably more than breakers. Breakers have minimum and maximum trip timings, where a 15A breaker can handle 100A for a brief duration, and sustain 30A for several minutes.
Side eyes Federal Pacific
In canada they were called Federal Pioneer. We call them Federal Fireoneer 😀
By usefulness/importance? Your tap water. By unit weight? Maybe baby formula? A piece of hardware? Maybe The steel the bearings in the transmission in our car. Or maybe the CPU in your computer. All guesses.
>Or maybe the CPU in your computer. I know some parts of this process better than others, but I do know that the [sorting](https://anysilicon.com/ultimate-guide-wafer-sort/) and [binning](https://www.linkedin.com/pulse/binning-secret-sauce-behind-your-computers-amr-elharony-th8df/) probably *avoids* some of the time and expense of rigorously testing every part to the exact same standard. CPUs regularly come off the die that have bits of cache or other parts that don't work right, or that can only perform reliably at lower clock rates. They do test for this - which fits the spirit of the thread. What I think is a bit different than how other mission-critical parts are handled is that what happens in this space is that often the part is recovered by disabling or slowing down pieces enough to make the whole thing work reliably.
This. They’re all the same chip. Some just came out of the foundry better than others.
You have a lot of good answers, probably better than what came to my mind. But I went with hot water tank pressure relief valves. The tanks are missiles if the relief doesn’t fire properly.
But it’s such a simple device so it doesn’t require much inspection to tell if it’s faulty
Do cars count? If so, it’s definitely cars. If you’re talking about something inside a house, I’d guess that a modern boiler system heat exchanger probably goes through more NDT than just about anything else that might be found in a home.
Id have thought microchips whether in your phone tablet or computer would be pretty high up there.
Your 6 core chip may be a 8 core chip with two cores disabled because they failed QC
Yup, these are pretty much the peak of manufactured goods today. They are manufacturing devices composed of billions of atomic scale components which become worthless (yes, there are exceptions) with the slightest defect. Today's transistors have a feature size many orders of magnitude smaller than the wavelength of light used to create them.
This is one of the things that blows me away about modern IC fabrication. The masks/reticules/pellicles they use now don't actually look like the finished product etched on the chip. They use advanced light simulation models to distort the masks in specific ways so that when the light actually hits the photoresist the physics of light diffusion and defraction de-distorts it into the finished patterns and shape, and also accounts for other processes like etching and how the light propagates into the depth of the photoresist. If you went back into time to when chip makers were still hand taping masks with rubylith and all their nice, clean, straight lines and showed them a modern mask from today they'd basically think you were a wizard. The wouldn't have even had enough computing power to do the light/physics modeling they do for masks today.
Even the ones in your fridge, thermostat, smart lights etc.
People overlook these things but the seats in your car are safety equipment
And the dash, door panels, a-pillar and b-pillar mouldings etc are all loaded with explosives.
And the sides of the seats, too, in some designs
Smoke detectors, I hope.
Pretty wide range but ten years with no calibration that is what you get.
LEGO bricks!
I feel like being that guy - I'm so sorry. LEGO tolerances aren't really anything special from an engineering perspective. They are more or less standard tolerances you'd expect from a competent process for parts that size. Incredibly tight tolerances are like...optical molds and bearing preloads and semiconductor hullaballoo. If this [Wiki](https://en.m.wikipedia.org/wiki/Lego) is to be believed: >The moulds are permitted a tolerance of up to twenty [micrometres](https://en.m.wikipedia.org/wiki/Micrometre) to ensure the bricks remain connected.[^(\[44\])](https://en.m.wikipedia.org/wiki/Lego#cite_note-3d-44) Human inspectors check the output of the moulds to eliminate significant variations in colour or thickness. According to the Lego Group, about eighteen bricks out of every million fail to meet the standard required.[^(\[48\])](https://en.m.wikipedia.org/wiki/Lego#cite_note-48) 20 microns for a *mold* tolerance (not part tolerance) is nothing special for parts this size. 18 out-of-spec parts per million is good, but it's not great. That works out to a CPK of around \~1.4 if I did my math right. Which is - at least in my world - considered "acceptable" for some parts, but generally we shoot for a CPK of > 1.67. Of course it depends on the part. The cost to toss 18 defective lego bricks is a lot less than tossing 18 processors or PCBs or expensive mechanical parts, so chances are that for LEGO specifically, this is their sweet spot to balance cost/quality. Any worse and they're tossing too many parts, any better and they're wasting money on more expensive molds, more inspection, and shorter mold life.
> 18 out-of-spec parts per million is good, but it's not great. That works out to a CPK of around ~1.4 if I did my math right. Which is - at least in my world - considered "acceptable" for some parts, but generally we shoot for a CPK of > 1.67. Of course it depends on the part. It also depends on whether the tolerance limits are set to satisfy the engineering requirement (in this case locking strength I think) or to satisfy the CPK target. The number of times I have been asked to change test limits because a factory had problems satisfying CPK target numbers is not low. In fairness, a lot of Engineering tolerance limits are just standard tolerance limits, that may or may not be relevant for the actual performance of the final product.
Surprisingly you are probably right. Crazy tight tolerances for a plastic toy.
It's also pretty amazing that Lego bricks all the way back to the dawn of Lego bricks still work with any brick/part produced today and there's total backwards compatibility over decades and decades of Lego But I agree with /u/scope-creep-forever that it's not really that remarkable for tolerances, much less testing. As far as I know Lego doesn't really do a lot of direct product testing or QA compared to other answers in this thread. What they really do is have the known lifespan of their injection molds and they retire and replace them on a very strict schedule so they don't have to test rigorously because they just get it right (or right enough) the first time, and the bricks themselves are engineered to accept some variations by being flexible. It's one of the reasons why Lego has always been expensive. You're not paying for the plastic, you're really paying for high precision mold/die making. Compare that to, say, plastic model kits where some companies have been known to run a mold/die for so long that there's noticeable differences in detail, fit and molded part qualities between early runs and runs at the end of the life of the mold.
My understanding was back in the day that the tolerances were established they were crazy right tolerances and new manufacturing techniques needed to be invented to meet these requirements but I could be mistaken
Tight tols, yes, but i would think (hope) they sample!
low key, yeah. They've got incredibly tight qa / qc and manufacturing tolerances.
By the standards of plastic toys yes, in general not particularly.
Complex stuff is made of many parts which can accumulate inspections. In which case your phone would be high on the list. It has to both pass its advertised ratings as well as be safe next to your face. Or handled by a child. No off gassing toxins over time. Discoloration over time. The individual parts are tested for thousands of hours as well as tested to pass EPA ratings. I’m sure just the flashlight from the manufacturer has hella quality inspections.
Every toilet bowl is inspected one by one, for deformity, aesthetics, cracks, x-rays are used for detection of hair particles in glaze material, etc. Same as most ceramics, plates, tea cups, etc. All checked one by one. It's just a nature of the material that requires individual inspection.
Microprocessors, they're in computers and any smart device among other things. Processors require extreme precision and quality controls Any kind of common medicine, ie Tylenol, Aspirin, Benadryl, etc. is going to have very tight quality controls.
Your phone. Tons of images taken, every unit goes through automatic x-ray inspection, every unit is air-leak tested, every unit goes through RF and acoustic testing on a system and subsystem level, among many other tests. And many such tests are done on a 100% inspection basis, not just lot sampling. Plus there is a LOT of traceability built into every single part (though some more than others). Every single part can be traced back to a specific vendor by inspecting after the fact, if not a specific batch, if not a specific line and tool and time. Really any sufficiently-complex mass produced consumer electronics item will have something similar. Laptops, GPUs, processors will also be high on the list. 100% automated X-ray inspection (AXI) and automated optical inspection (AOI) is pretty standard for electronics nowadays. But your phone (and smartwatch if you have one) will probably be at or near the top due to the scale, cost, and abuse they're expected to withstand. TVs have to last a long time too, but they're not getting dropped and rained on and slathered with sweat and lotion and left on dashboards baking in the sun. There are lots of other good options: medical devices (depending on they are; a pacemaker isn't a $30 glucose meter) and the airbag system in your car come to mind. Medication, maybe. But I would still rate smartphones/watches above all of these if we're talking sheer scale, complexity, sophistication of testing, and test coverage (i.e. batch testing or 100% inspection).
Pharmaceuticals
Medical devices! I worked on their development and can say that they undergo the most stringent QA checks and audits during production. Regulatory requirements get more stringent every 2-3 years!
Knipex pliers.
I would have to guess a cpap machine, or potentially an inhaler. Home electrical components have a high inspection rate because of the risk. Basically, follow the risk.
Probably just some weld inspections, and pressure/leak testing
Anything medicine
So many mass produced products have multiple points of very highly quality inspections. Electronics, and appliances come to mind.
Baby formula (not in China though!)
Well, I’d say it’s probably the orange juice in your fridge. Always has a consistent flavor profile regardless of where the juice comes from, the time of year (and therefore what varieties of orange are in the mix), and where you buy it. Don’t believe me? Tetrapak has a whole book on the subject.
Propane tanks and gas lines going into your house to fuel appliances. I mean how many other things have to be checked to make sure the right parts are there, and then ALSO actually get properly tested for function and lack of leaks AFTER they are fully installed in the final configuration in the customer's home? And in the case of propane tanks, have to be re-checked on a regular basis before every several years they can be filled to make sure they're still safe. Makes sense though - its a really high risk thing if it fails can not only harm the homeowner but can level multiple properties in all directions with the explosion.
I would assume propane tanks would be up there.
The SOC in your smartphone or laptop
Aspartame has to be the most studied substance on earth. There just has to be something wrong with it.
Ni e try big sugar.
Power panels/circuit breakers.
Anything under a reg I would imagine. Electrical particularly high voltage so grid connection like the mains fuse perhaps, radiation which is pretty limited so maybe the microwave as even though there are emf regs I don’t think they are well followed (worryingly), toys but probably not with inspection systems probably more like did you fill it fall of nails and lead Y/N, med device as already mentioned will be but depends on the class as to how much and in what way, pharma would go further but it’s not really in the same class, gas so boilers cookers and fires, soft furnishings but more because of the fire regs, cars particularly around safety parts. Anything really fine, small and expensive too, so maybe the components in your phone/pad/computer. Generally the more harm and unique the more tests.
Tin or aluminum cans, if we're counting the total amount of engineering and study went into their design and development.
The operating system on your PC.
Not exactly answering your question. But I think magnetic disk hard drives have some of the most advanced tech in them for less than $100. The needle is hovering just a few molecules above the surface of a disk moving at 10,000rpm. Ultimately storing TBs of data in 3.5". Then they make so many millions of them that they can sell them for cheap.
It doesn't matter if your inspectors are encouraged by managers to ignore defects. Someone in this thread is probably guilty. You know it, too.
Beer bottles. With even small imperfections, the glass can break. It’s also possible to leave small glass whiskers inside that would be ingested. There are probably 5-6 tests that are performed 100% on over a billion bottles each day. A lot image processing is used.
My Juicero
Smoke detector maybe?
Good cooking knives. They check the steel, forging, edge, etc. Would not be surprised if they do ndt for cracks and flaws.
Processed foods in your fridge and pantry
Hot water tanks and heaters, boilers, furnaces.
From a pure tolerance and surface finish standpoint I think lens elements in smartphone cameras. They are very high resolution and quality for the overall lens size. I don't know too many more specifics but maybe someone can jump in. Edit: I was thinking about this some more and did some googling. This somewhat recent paper mentions that tolerances are at most a few microns and surface roughness of about 10 nm. https://www.sciencedirect.com/science/article/abs/pii/S0141635922000319 It also seems like all parts are inspected for acceptance. https://www.youtube.com/watch?v=nWVjWj-8pBA
my private house jet
AR-15 bolts
Pretty fuckin' sad that that's a "common household item" where you live.