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Those cafes are a great idea! I recently opened a high quality blender (forgot the brand) and found a cog made partially of metal with one small part made of pl

Those cafes are a great idea! I recently opened a high quality blender (forgot the brand) and found a cog made partially of metal with one small part made of plastic which will break first due to wear and tear. Otherwise this little motor would run forever. Is it normal these days to put in breaking points to artificially shorten the life of appliances or does this have a purpose?

sevensor 9y ago
That little cog might be more like a fuse -- a part of the system that's relatively easily replaced and designed to fail first.
- pbhjpbhj 9y ago
  And so the company send a spare one in the box when you buy it, yes? Because they wouldn't be so crass as to make you hunt down a part that cost them a few pennies and disables the machine would they? Same issue for me with food mixer, mostly metal, key part is plastic and gets stripped, can't be replaced. Same with bread maker, rubber belt decays and company don't make the part available.
  - sevensor 9y ago
    Right, that's a fair criticism of the business practice, but from an engineering perspective it might not be a terribly unreasonable design. It's a good idea to design a system to fail predictably. Electrical engineers use fuses, mechanical engineers use shear pins, and so on.
  - lopmotr 9y ago
    Perhaps it was to protect the user, not the machine. If you drop a spoon in, it might break the fuse before pinging it into your face? Or it might have been a sliding contact that needed better wear performance than metal on metal, or it might have been an odd shape that was expensive to make from metal.
- rdeboo 9y ago
  Outboard motors for boats work like this. If you hit a rock with the propellor, a piece of plastic in the drive train breaks. This prevents the propellor or some other part of the motor from serious damage.
KamiCrit 9y ago
The plastic component could also be acting as a mechanical fuse in case of overload. Like a shear pin.
- Lunatic666 9y ago
  That would make sense, instead of breaking the cog-setup, the little plastic part breaks off and saves the motor. Thank you for the explanation, one conspiracy theory less!
voxadam 9y ago
It's called engineered obsolescence.
- jimktrains2 9y ago
  Or mechanical fuse as someone else pointed out: something cheap and easy to replace that will break before something expensive and hard to replace when over the design load.
klunger 9y ago
Yes. As others said, it could be a mechanical fuse. However, engineered obsolescence is a real possibility. A friend of mine had a product manufactured in China. He said the factory he partnered with asked him straight-up "Where do you want the weak part? When do you want it to break?" So, I guess it is pretty standard practice to do this (admitted anecdote here, but still)

sevensor 9y ago

That little cog might be more like a fuse -- a part of the system that's relatively easily replaced and designed to fail first.

pbhjpbhj 9y ago
And so the company send a spare one in the box when you buy it, yes? Because they wouldn't be so crass as to make you hunt down a part that cost them a few pennies and disables the machine would they? Same issue for me with food mixer, mostly metal, key part is plastic and gets stripped, can't be replaced. Same with bread maker, rubber belt decays and company don't make the part available.
- sevensor 9y ago
  Right, that's a fair criticism of the business practice, but from an engineering perspective it might not be a terribly unreasonable design. It's a good idea to design a system to fail predictably. Electrical engineers use fuses, mechanical engineers use shear pins, and so on.
- lopmotr 9y ago
  Perhaps it was to protect the user, not the machine. If you drop a spoon in, it might break the fuse before pinging it into your face? Or it might have been a sliding contact that needed better wear performance than metal on metal, or it might have been an odd shape that was expensive to make from metal.
rdeboo 9y ago
Outboard motors for boats work like this. If you hit a rock with the propellor, a piece of plastic in the drive train breaks. This prevents the propellor or some other part of the motor from serious damage.

KamiCrit 9y ago

The plastic component could also be acting as a mechanical fuse in case of overload. Like a shear pin.

Lunatic666 9y ago
That would make sense, instead of breaking the cog-setup, the little plastic part breaks off and saves the motor. Thank you for the explanation, one conspiracy theory less!

voxadam 9y ago

It's called engineered obsolescence.

jimktrains2 9y ago
Or mechanical fuse as someone else pointed out: something cheap and easy to replace that will break before something expensive and hard to replace when over the design load.

klunger 9y ago

Yes. As others said, it could be a mechanical fuse. However, engineered obsolescence is a real possibility. A friend of mine had a product manufactured in China. He said the factory he partnered with asked him straight-up "Where do you want the weak part? When do you want it to break?" So, I guess it is pretty standard practice to do this (admitted anecdote here, but still)