Also, plastics that last very specific amounts of time are common in specific pieces of assemblies in mechanical timers for refrigerator defrosters and the little crossbars that tie the vanes in air vent directors together. Replacement timers use all nylon gears and last “forever”.
The one I personally uncovered is a Honeywell thermostat. It is a direct replacement for a mechanical thermostat that would frequently fail about 10-15 years out due to corroded/pitted contacts. The all electronic replacement does not have this problem, but they still failed around 10 years out, but with remarkable predictability in my friends apartment complex.
I reverse engineered one. It is powered by the 16-24v signal line. It uses a simple potentiometer to set the temperature, no clock, memory or other features. It has a battery soldered on the circuit board. The battery slowly discharges while the unit is on. In about 10 years of operation, the battery voltage drops below 1v or so. The battery powers nothing, but the microcontroller senses it’s voltage and when it is too low, it changes the behaviour of the thermostat to randomise the temperature cut in/out points by about 10 degrees Fahrenheit , making the thermostat annoyingly unpredictable in a way that is very similar to the typical failure mode of the old thermostat it replaced.
One notable difference is that the electronic one will never fail (unless it is in the off position) to come on at 45F or lower, preventing the programmed random behaviour from provoking a freeze-up and damage to structures, so I guess that’s nice?
Wow what an abhorrent waste of talent and life.
If the engineer took some existing product and did nothing for 2 years other than design in additional failures that show up after the warranty has expired, I agree that's awful. However, I'm very skeptical of that. I've worked in some manufacturing orgs who try to pinch every possible penny they can, and I've never seen anything resembling that level of mustache-twirling villainy in engineering. Also, 2 years seems like an incredibly long time for someone to spend doing this and nothing else.
It's much more likely that the company asked the engineer to reduce the cost of the pump while still hitting the product's requirements (e.g. no failures during warranty period plus some margin), and while doing that, the engineer found the design was overspeced for those requirements and made some changes which reduced the pump's expected lifespan while still meeting that requirement.
Unlike what the OP is suggesting, this happens constantly...it's what engineering is.
Obviously I'm not OP and I'm reading between the lines here, but it's very easy to imagine someone hearing this story second-hand and completely misrepresenting it.
If the old pump failed, it often did so in a way that caused additional warranty expenses and reduced reliability perception. The problem was that a seal failure could cause catastrophic bearing failure.
So, the new pump was designed so that a seal failure would not cause bearing damage. Good sealed Bearings properly specced are very reliable these days, and seals on a true shaft wear very little. The problem was that the new pump would invariably make it to EOL.
So after spending a few weeks designing a no-fail pump, they had him redesign it so there was criticality in one of the bearings, so that one was effectively overloaded and would develop enough play to cause seal wear, (and dripping) while the other bearings would prevent the shaft from actually failing. The thing is, it’s hard to spec a bearing for “will wear a little out of tolerance but won’t fail” so it took two years and a lot of testing to get it right.
In all, there was a considerable amount of moustache twirling going on. But not as much as in those damnable disintegrating plastics or the unneeded battery in the thermostat.
Before anyone brings it up: sure, a lot of companies just pocket this savings or whatever, but a lot don't; you just don't hear about them because they're typically midsize companies that nobody complains about.
It matters whether the focus is on reducing costs while keeping track of the impact on the product's lifetime, or the focus is on reducing the product's lifetime. What I'm calling a waste of talent and human life is spending time on the latter, and that's what it sounds like my parent comment describes their engineer friend doing.
Yes it is. At the absolute limit, balancing cost and reliability is this exact optimization exercise; we are talking about the exact same thing taken to different extremes. The difference between your ideal scenario and the practice outlined in the OP is the difference between 97% BOM efficiency and 99.99% BOM efficiency. At extreme scales, that gap can mean the difference between a company laying people off vs. surviving.
Side note - this same discipline is what ensures your widgets fail in a safe, controlled manner and not in a catastrophic way.
> I feel like you're reading my message extremely uncharitably
I saw an naive take on how mechanical design for failure works in practice and wanted to educate. I mean no disrespect, it's just seemed like it might be an unknown unknown for you. Your comment had at least a few upvotes, so there are others out there who may also lack the same information.
To your charitability point, though, my first take on the OP above is probably the most charitable take. The least charitable scenario for the OP is that the company wants to make sure they have higher annually recurring revenue from replacing their widgets breaking down but need to _barely_ beat or match the other guys in a warranty. Reality is probably somewhere in between.
I traced the circuit, it goes between ground and the uC pin, through a 1 Mohm resistor, no other connection. It’s about right for killing a 300mah battery over 10 years. The pin is held low when the unit is energized by the thermostat signal lines.
It depends how much of the BOM price was the battery.
This should be criminally investigated and the person who ordered it be put in prison for at least a decade.
I think it would be best to focus on the deterrent effect for the future: we need a law that makes this business strategy not viable. Not on punishing bad behavior that already happened. Maybe such law already exists, but we need more enforcement. Or a better thought out law.
I don't think it's important if _that_ person gets jail time. I would not particularly rejoice at the news. But if somehow this practice was made impossible or impractical, I'd
Some people might be fine with a product with a known lifespan, or want to pay more for the unlimited life version
The penalty should be more like corporate death than individual prison, as that often gets fobbed off on some scapegoat rather than on the actual manager responsible
We can’t send arbitrary people to jail for bad designs. I don’t think many people would be an engineer if you knew there was possible jail time if you shipped something with a bug.
At the time I was just focused on why my buddy was having to replace 200 thermostats in ten years. It turned out you could just cut out the battery with a pair of dikes and jumper the leftover positive post to 3v to get basically unlimited lifespan, so he did that instead of replacing the thermostats with new ones. Afaik most are still working fine.
Helping him out is also how I figured out the defrost timer disintegrating gears thing. When you do things at scale, things that seem random in onesies practically scream at you. It made me appreciate the value gathering data…you can find the patterns at lower scales.
The car air vent thing I figured out on my 94 Toyota 4runner. The air vent crossbars that keep the vanes in alignment with each other all failed over a two year period. A minor annoyance, but it makes you feel like you need a new car lol. I popped them out and found that of all of the plastic parts, only the crossbars were exceptionally brittle. Suspiciously, the bars also had what looked like date codes molded into them. None of the other pieces had numbers at all. I just printed new crossbars.
This is really neat, if true, but I have to say I'm skeptical. This is just too good a story!
I am not an electrical engineer. Could the microcontroller use the battery as some kind of calibration? Or could it have another function?
Just this weekend, I saw a headline that the Looney Tunes box set I bought then probably doesn't work anymore, because Warner Bros used crappy materials to mint the DVDs and people have had them degrade beyond playability.
https://en.wikipedia.org/wiki/Nitrocellulose#Nitrate_film_fi...
https://www.youtube.com/watch?v=uQwQRFLFDd8
Obviously DNR and bad HDR jobs are kind of their own issue, but he focuses specifically on coloring and the notion that theatre prints are themselves often wildly inconsistent and change over time, so it can be extremely difficult to even establish a baseline for what a film was meant to look like or even what it actually looked like upon release.
As a modest 4K collector myself, it frustrates me when certain films seem to sit in indefinite limbo, but Amadeus (released this week) looks fabulous and was absolutely worth the wait, so I have hopes that the people taking their time to do right by films like Ben Hur and The Sound of Music are doing so for the right reasons.
In an interesting way it's almost that human memory is the most durable format -- as long as we remember to care for and preserve information, we can keep it around as long as people are around; But once people stop caring about it, eventually it will fade.
https://en.wikipedia.org/wiki/Long-term_nuclear_waste_warnin...
Also, ray cat memes: https://99percentinvisible.org/episode/ten-thousand-years/
The old film stuff which survives is mainly due to material quality, storage and luck, in that sequence. Those DVD started already losing the battle.
If you have anything worthy still on DVDs that still works, make a backup to keep it.
Luckily this was all stuff I had no issue with discarding, but if those discs had contained anything of sentimental value, I'd have been quite upset to find that they were basically useless now.
> If you have anything worthy still on DVDs that still works, make a backup to keep it.
And make sure to make it to multiple other formats, preferably including some sort of cloud storage. Solid state storage, especially modern small portable drives, are great if you use them often, but if you're planning to just copy stuff to them and leave them sitting unpowered for a long time, you should be aware that over time they too will suffer from data corruption. The charges in the storage cells don't leak fast, but they do leak.
You gotta actively maintain your backups, even if that just means plugging the backup drive in every other month to check its' health.
Most 1980's CD's are still fine, except for ones made by PDO UK.
I'm not sure if the glue layers in DVD are organic or not, but I think the rainbow part itself is aluminum.
Having a non-user replaceable battery is a really easy way to ensure a product stops working after 3-4 years though.
And the criticism is typically directed at companies like Apple, who does make things that last physically, but then force you to upgrade by way of battery.
IMO the durability problems in early generations of products tend to be "real", because there are still real engineering problems that aren't understood, and there isn't (generally) a super limited market. Once the engineering problems are solved and the market is fully saturated, there is suddenly an incentive to add planned obsolescence. I don't have any data to back up this claim though.
If you have a product that's been in the market for a while and it looks like it's meeting service life expectations you start looking at it trying to find ways to save money by substituting cheaper parts. You swap out metal gears for plastic gears, for instance.
If these parts have a shorter service life, but the service life is still longer than the warranty, then maybe that's a win in two ways for the manufacturer.
Great, till the motor that drives the gears jams. When the gears are metal,the expensive part (the motor) is more likely to lose. When the gears are plastic, the motor survives and you need to replace the gears with nylon ones or 3D print your own.
The plastic gears may not always be designed as a sacrificial part, but most consumers unfairly dismiss the possibility immediately
This comes down to warranty too. If it fails during the warranty period, which one does the OEM want to pay to replace: the expensive motor, or the cheap gearing?
Modern phones are examples of too much power for too little reason as far as I am concerned.
That’s not necessarily malice. Using lots of glue makes the device stronger, and making glue that a) glues really well (if there’s as good as no bezel, how is the screen staying attached to the phone otherwise?), b) lasts for years in any climate and c) can be easily removed isn’t an easy problem.
So, how do you screw a thin piece of glass onto a phone that doesn’t have bevels to speak of in such a way that you can put it into your pocket for years, and push a finger on the center of the screen tens of thousands of times without breaking?
Also, if there’s room below the screen, the screen will bend more than when there isn’t, and that will affect longevity.
I’m not claiming using glue wasn’t done out of malice, just that we can’t say it is.
In any case, all it takes to repair a phone with a glued screen is a two face suction grip for about 20 dollars and an ordinary hair dryer.
The nasty part of a phone repair, I will admit that, is scraping off the glue gunk - I had to repair a Google Pixel once where the battery was dead, and during removing the glue on the display unit border I apparently managed to damage the seal between the OLED display and the glass, exposing the OLED to oxygen which led to eventual oxidization and a new display panel.
Which is a positive in my book, it means I know where to start if I need to get into the thing.
Apple has a high profit margin on their products so I expect better. This isn’t a cheap laptop from a supermarket.
I suspect this is a classic example of corporate beancounting at work, even if it just a dollar or two per machine, at Apple's volume of millions of machines that's nothing to sneeze at.
To fix it, we need laws that require a certain repairability score for all devices sold. Then doing the "right thing" would be a KPI that competes with pure financial incentives.
They make a high margin on each device and other manufacturers can manage it fine at similar price points. I believe it was deliberate, they back tracked after being highly criticised for it.
> To fix it, we need laws that require a certain repairability score for all devices sold. Then doing the "right thing" would be a KPI that competes with pure financial incentives.
If people are concerned about repairability they should seek out manufacturers that offer products where they have a good track record.
Laptops, tablets and phones are seen as partly consumable by the majority of people and they replace them every few years. I am not saying that it is right, I am just saying that is the reality. Also not every problem can be legislated away and if you make something a KPI it will be gamed.
They also made a massive improvement by designing an adhesive for the battery that detaches with electricity. So you no longer have to use pull tabs or heat.
Things like fatigue failure, surface wear, vibration, corrosion, etc. and super hard. Entropy is a real bitch and it comes for everything.
They spec’d out too low temperature rating of a capacitor that was right next to a heat source and cook itself to death:
https://m.youtube.com/watch?time_continue=315&v=BQM4ERy-wpY
https://electronupdate.blogspot.com/2017/12/leviton-ltb30-bu...
So yeah, tried too hard to save 2 cents
Like they say that anyone can overbuild a bridge but only an engineer can make it barely stand up. A lot of that cost cutting is useful but it tends to go too far.
The majority of biggest suspension bridges if I remember correctly are barely standing up. They use above 80% of the cables carrying capacity for themselves.
1) They're a relative benchmark. They don't represent how the product will perform in absolute terms, only how it will do in this standardized bench test against other products.
2) They might miss some things that are coupled together that don't fully get felt out until you're over longer periods of time.
3) They're imperfect if the use cases for a consumer product will be complex. An easy example is a car. Auto OEMs will try their best with their standardized accelerated testing scheduled for durability, corrosion, etc -> but the consumer will always end up doing shit that is totally reasonable but not in the accelerated testing scheme )or under provisioned).
4) For complex products, a lot of accelerated testing might happen on only a subsystem level and may not fully map to the final product.
Although these downsides are real, accelerated testing is still great and, with good planning and experience, can catch a lot of problems.. but it tends to always miss something and the above 4 points can synergistically work together to make a "design big" more obvious when in the field/hands of the customers!
Once you’re close to the engineering side of physical products you also realize how hard it would be to make products that break down precisely after the warranty period is up. Most failure modes get spread out over a very long time (years/decades). Attempts at intentional obsolescence would start cutting into your warranty period very easily.
What are the economic consequences of warranty claims if you products are cheapened to fail after the warranty expires?
Have you not heard of enough of penny-pinching electronics fails (a device worth hundreds $ failing due to low quality part worth cents)?
First, you're not blind - you can test your product to see what the "plenty" is.
Second, many components have rated use, so it's easy to estimate mean time to fail and pick the one beyond the warranty period with whatever buffer you like. It's not like you need seconds level of precision here!
Or, I don’t know, perhaps giving slightly greater consideration to the people in this thread who’ve actually worked on physical device engineering?
(and no, you don't need "reliably ... specific and precise", those are just artifical constraints you've added)
And don't speak for everyone, not everyone is so clueless re. business decisions just because they've designed some hardware.
I’m not convinced some of my very expensive smart products aren’t intentionally degrading over time, given fw is introducing more functional bugs.
Pre OBD2 cars just didn’t do that. 100k was a significant milestone for the life of the car. Today, it’s a preventative maintenance milestone.
Shitty plastic parts aren’t a feature of modern cars, just lousy companies. I had a 1991 Dodge Spirit in college and high school that had a little plastic part in the distributor that broke when it got hot.
When it did, the car would just stop if you hit a puddle or turned right quickly. It did so enough that I kept two spares in the trunk. One time the car died on the ramp from the GW Bridge to the West Side Drive. I just stopped on the ramp and fixed it, pissing off hundreds of people in the process.
Doubt that
>Pre OBD2 cars just didn’t do that
In Eastern Europe, if the car has 200k-300k km on the odomoter, it only means one thing - the odometer is turned back. Pre OBD2 doing 500k and up is pretty normal here.
>little plastic part in the distributor
Distributor was always plastic, afaik. I'm talking about plastic water pumps on the new BMWs
The Bureau of Transportation indicates that the average age across the board for vehicles still on the road is just over 11 years according to Autotrader, and the average may be approaching 12 years. Standard cars in this day and age are expected to keep running up to 200,000 miles, while cars with electric engines are expected to last for up to 300,000 miles."
https://www.caranddriver.com/research/a32758625/how-many-mil...
Your average shitty 4-banger from the 80s or 90s is not remotely comparable to a new engine - in almost every respect (including reliability!) the new one is better.
The labor costs ALONE make that a horrible idea for anyone who isn't a mechanic already - and if an engine lasts ten years the depreciation on the car is intense enough that it doesn't matter.
A lower quality component is cheaper than a higher quality one that would last longer, so that's what ends up being mass produced, and that's what you, as a product designer with no power over the entirety of the production pipeline, has to work with.
People pay a lot extra for Toyota.
I don't want to pay extra for my pants to last at least a full year (think 100 days use, 30 wash cycles), or for my electronics to last at least five years since I am old enough to remember that this used to be absolutely normal and the way things used to be.
All these companies some of us remember are all now owned by the same company. This is how capitalism goes. Eventually, a company makes a mistake, and a competitor will absorb them.
This is dramatically simplified, but the big joke is that capitalism breeds competition and that is good for the consumer.
The illusion of choice via mergers and acquisitions.
At what rate of return does "profits" turn into unbridled greed and capitalism turns into parasitic exploitation?
…and that’s where the regulator needs to step in and establish a set of requirements which must be met to allow profiting.
They were often tested to ridiculously high standards with huge voltages applied across strenuous tests. And they cost accordingly.
It’s amazing how cheap things are these days. I think what frustrates people more is that the more expensive options don’t usually last long. Finding the more reliable option is fiendishly difficult and it may not exist.
Yeah, well put. Just had to replace a dishwasher, and among the models of one brand it seems the more expensive models just add more moving parts and complexity that, ironically, may lead to more issues.
Don't get me started about clothes. The quality and weight of the fabric is almost completely disconnected from the price.
A lot of depends on where your price point is. Do you compete with Temu or do you sell expensive things. People rarely expect cheap things to last, but if you don't compete on being the cheapest, than the product is expected to be made to last
Details if anyone is curious: https://www.reddit.com/r/printers/comments/r04j3s/trying_to_...
The issue turned out to be the solenoid for the pick-up mechanism. When activated it should cause the pick-up mechanism to turn once. The solenoid once apparently had a small rubber pad to reduce noise. This had turned into goo and the solenoid would stick causing the mechanism to turn multiple times.
Fixed by removing the left-over goo and a piece of tape. Ten minute fix.
I guess that we've all had some kind of gear that still works fine, but the rubber coating is all tacky and nasty, and leaves smears on your hand.
I had to toss out a bunch of really good mice because of that.
Generally, I try to avoid buying anything with rubber. It is usually the first part that goes bad. Either it gets sticky and starts melting or it gets hard and dry and breaks up. Also, I avoid using rubber bands. They usually end up damaging objects they hold together.
Here's a good page about conservation of rubbers and plastics for those who like to preserve their vintage stuff for a long time. https://www.canada.ca/en/conservation-institute/services/con...
This is not to say all plastic is this way, some plastics that are more flexible, like on the gas containers themselves, can last for years. But the cap rings are made of hard plastic.
The problem is on many models they were meant to bend some to release a clip, for example to open the top of a case.
Or they just can’t hold the stress they were supposed to, like the display hinge attachment points on many classic Mac laptops.
This morning I replaced the rubber grip on my manual coffer grinder. By my math I'd ground about 40 kg of coffee by hand over 4 years, and the grip had gotten to the point where it just spun around the body of the grinder unless held very tightly.
I assume I could extend the lifespan by wearing gloves when I grind coffee to keep my hand oils off the rubber, but the replacement was only $5.
Didn't work for me. Still sticky and messy, with the added benefit of adding schmutz from the cloth I used.
And change the paper towel frequently. It works by dissolving the sticky stuff, not mechanically wiping it off. So the paper towel picks up the dissolved crud after only a few wipes, then switch to a clean one.
I’ve cleaned cameras, mice, umbrella handles, and the back of a Samsung tablet this way.
"Rubber" means lots of different plastics, some of which are very stable and some of which are very unstable. Some are natural; others are synthetic. All they have in common is that they are soft and very elastic—if even that, since sometimes ebonite is called a rubber as well, comprised as it is in large part of natural latex rubber.
Silicone rubbers in particular are extremely stable.
What are steering wheels made of? That material seems to last longer, and they exist in much harsher conditions.
As I get older I wonder how may of my burned DVDs will still work.. My MiniDiscs still do as of this fall when I dusted them off (different technology). I had heard of tv networks "baking " magnetic tapes to get the information off.[1] https://en.wikipedia.org/wiki/Sticky-shed_syndrome
Figuring I had nothing to lose, I turned it over and squirted some 3-in-1 oil on the motor spindle. The whine started increasing in pitch as it quietened, and slowly the HD benchmark program started creeping up toward a more reasonable 1MB/s or so. I didn't use that drive afterward, and just copied the, ahem, public domain apps and games off it and then threw it away.
I have not before or since sped up a computer by oiling it.
I was wondering whether the flat tape makes some cylinders physically inaccessible but it seems like this is not an issue.
Bought at an Egghead somewhere the Computer Museum in Boston while on vacation from the UK -- about half the price of something similar in England at the time due to exchange rate.
The airflow while the platters are spinning keeps dust off them, and as long as particles don't stick and cause excessive "thermal asperity", the heads will still work. The latter is what makes transient bad sectors appear.
https://www.ifixit.com/Guide/Pentax+ME+Super+Mirror+Box+Serv...
The ones without such an issue is still often recommended for hobbyists who want to get into analog photography today, because they are generally inexpensive, compatible with very nice lenses, and there are so many of them circulating still for parts and repair.
Given that they were made in the late 70s to early 80s, and the shutter mechanism is fully controlled by electronics (instead of mechanical), it's quite amazing that the rest of the camera mostly held up over nearly 5 decades.
I don’t think any kind of capacitor is a semiconductor.
(But this approach fails on the temperature coefficient of resistance test: capacitor ESR increases with temperature while semiconductors have a negative coefficient.)
This is a very old package design from the transition between through hole and SMD. The process for making the vertical axial style common now hadn't been perfected and it was briefly cheaper to cast regular axial caps into an epoxy block.
No other component looks like this, it's a very distinct package and footprint from any other type of cap. No one tried to disguise anything, they really just thought this was the cheapest way to make a surface mount electrolytic cap.
Semiconductors actually are pretty stable long term.
The capacitors that go bad tend to be the electrolytic ones, and there aren't a lot of those on things like hard drives.
After many years of storage, the rubber belts had become fragile and any attempt to move the magnetic tape turned the belts into dust, making the cartridge unreadable.
The LTO magnetic tape cartridges used today are much more robust, because the cartridge is simpler and it hopefully no longer includes any parts that are susceptible to rapid aging.
At that time, i.e. 30-40 years ago, rubber belts were used because they ensured in a simple mechanical way a constant moving speed for the magnetic tape. Later, the electronic alternatives for ensuring a constant tape speed by varying the speed of an electric motor have become cheap enough to eliminate the need for such belts.
Low-density polyethylene would have been the better choice for longevity, but not so much for shock-absorbtion.
LDPE foam exists, but I think it wasn't common yet at that time.
[0] - https://www.flickr.com/groups/891454@N24/discuss/72157680498...
The tolerances are so tiny, I doubt it takes much at all.
Before opening it I'm going to try it in an older desktop as it may be that it just doesn't like USB IDE enclosures.
Now to find a SCSI card and cable ...
