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Why Do Gadgets Break?
TurboTurnip writes "A post on the Crave blog at CNET asks: Why are modern consumer electronics so easily broken? It argues that the 21st Century is 'The Age of the Flimsy' where 'your gadgets will simply break within the year.' Post author Chris Stevens talks about how computers are fast enough for the average user, and the only way to make consumers upgrade is 'increasingly poor build quality ... Engineers have built obsolescence into mass-produced technology since the 1920s. There are two kinds of planned deterioration in a product: one is technical, the other is stylistic.' The writer compares the build quality of a 20 year-old IBM XT to the modern Motorola Razr phone and concludes that modern gadgets are 'delicate, beautiful supermodels that can't go the distance.'"
Actually everything but the body is much more durable, but auto body is much harder to repair today, at least in some ways. Back in the olden days people used to do metal finishing on cars, which means that there's no filler used whatsoever. This is still fairly common on show cars, but on nothing else. Basically any damaged metal is either beaten back into shape (stretching and shrinking as necessary) or cut out and a patch welded in. If the body man can't repair the damage with hammers, dollies, and a torch from that point, then if anything, lead is used to smooth out surfaces.
The new way to repair auto body is to get it within 1/8 to 1/4" (hopefully closer to 1/8") and then use body filler. Depending on who you talk to the filler is either spread over bare metal or primer. Either way it seals itself to the body in a way that lead doesn't. Then you prime the hell out of it because any non-plastic filler (plastic filler is expensive) is hygroscopic and attracts water.
Okay, so with all that said; modern automobiles are made of a much harder steel than old ones. I'm not sure when the first 100% high strength steel car was made, but I know Mercedes did it in 1981 if that's any help. Today basically every vehicle that is not a full size truck uses a unibody design consisting of 100% high strength steel. Besides its various other characteristics which are not very important right now, HSS is hard. The harder steel is, the harder it is to work, and the more brittle it is. It's also easier to push it past its elastic limit, which is the point at which deformation becomes permanent to some degree. This makes metal finishing of modern vehicles all but impossible which is why we have to use filler.
But on top of that, they're all unibody vehicles. If you get a chance to inspect a modern vehicle which ran into something fairly straight at high speed, open up the trunk and lift up the carpet. Odds are you'll see deformations in the floor of the trunk area. When a unibody vehicle takes a serious impact, the force is spread throughout the vehicle. This is what makes a unibody car so much safer than a full-frame vehicle like, for example, a 1963 Lincoln Continental. Oh sure, that continental might weigh 5000 pounds, but it won't crumple when it hits a wall unlike a 2000 pound honda civic; furthermore, the stress is not distributed throughout the car. These two things combine to make it as if YOU had simply hit the wall, in comparison to being in a unibody vehicle with crumple zones. The unibody is so successful at transmitting force that up to 40% of the force of a front-end collision can be transmitted to the back of the car through the windshield.
Anyway, repairing banged up sheet metal is literally twice as hard as it used to be, if not more. Repairing torn up plastic parts costs just as much as buying new ones - the plastic weld compound is quite spendy and you need to use a special primer to get anything to stick to a polyurethane part. This is not the problem. The reason it costs $5000 when you hit a deer is that the body shops are continually getting away with insurance fraud. For instance, I rear-ended someone (I know, I'm an idiot) with a silverado. I bent his bumper and the brackets. The body shop ordered a complete bumper kit instead of the bumper metal and the brackets. Because they bought all the plastic bits that weren't even damaged, this raised the price of the job by $400. They also charged four hours of work to replace a bumper. This is a job that would take me maybe half an hour.
I took two years of auto body and paint classes from a body man who has been in the business long enough to have repaired cars with lead back when it was simply the way things were done...
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Also, for some very very odd reason, after around 18 months, the solder joints begin to somehow grow little spikes and cause pins to short out.
Ah, tin whiskers. An extra-special gift from our European friends.
Welcome to the Panopticon. Used to be a prison, now it's your home.
To have a gear or cam designed to break under mechanical overload is stupid. The proper way to provide a mechanical weak point is to use a shear pin. This is a plain cotter pin in an accessible drive shaft coupling, or in the hub of that gearwheel, that will shear under overload. It may be mild steel, or even aluminium in a light mechanism. Such a part is much cheaper to replace than a gearwheel, and can even be made by the user with basic workshop facilities rather than having to go back to the manufacturer.
Shear pins are common in machine tools for example, and are the mechanical equivalent of a fuse, which answers your point about electronics.