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I am planning on buying a kitchen stand mixer with planetary action.
One important factor to consider is the type of gears the mixer uses, they can be plastic, composite or metal.
As far as I know metal gears are the best and plastic the worst in terms of durability and handling stress.
However I don't know what are composite gears and how they fare, compared to metal or plastic.

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Composite is a very broad term in engineering - it's essentially any material that is made of two or more substances merged at macroscopic level - so not a mixture or alloy. This may be just a mix of larger grains, or it can be a complex structure.

One most common composite is reinforced concrete, where structure of rebar is embedded in concrete. Another is carbon fiber reinforced polymer (CFRP), where a texture/fabric of carbon fiber is embedded in a resin. Even plain concrete, even if rarely defined as such, is a composite - cement binder plus gravel.

In mechanisms, composite is usually the middle ground between plain polymer and metal. This may be metal-reinforced polymer (thin sheet metal gears embedded in plastic for stability), or it may be a CFRP cut-out, or a gear with metal axis mount and plastic teeth. Or it may be plain plastic with some waste organic fiber (cotton) added, increasing its strength insignificantly.

It's hard to say without knowing the exact device in question, and while that may be something of performance quite comparable to metal, the marketing department can get away with the buzzword to peddle a total BS that way - any additive that won't dissolve in plastic will make the plastic "a composite" regardless of any performance gains - or losses.

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I am not sure if it is a thing to buy. There is a composite made of thermoset plastic (hard plastic, e.g. epoxy resin...) with fibers embedded in it to give it more strength. I have personally had such a gear in my hands and it's hard I can tell you that.

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  • $\begingroup$ Not sure I understand, but I think I just realised "composite" means made from different stuffs, so it is unknown how strong these gears are until their components are known? $\endgroup$ – mathgenius Feb 8 '17 at 8:53
  • $\begingroup$ Yep, composite, meaning composed of two types of different materials. $\endgroup$ – MechHawkey Feb 8 '17 at 8:55
  • $\begingroup$ Well if you know what carbon is, then you know it is 4 times stronger than steel. Other composites are not as strong but you get the idea. Composited were invented because of the different properties we want to achieve. $\endgroup$ – MechHawkey Feb 8 '17 at 8:58
  • $\begingroup$ @mathgenius Composites can also have other features like fibres aligned to a grain. That can give properties like dimensional stiffness, compared to the generally uniform assumption we use with materials like plastic or metal. $\endgroup$ – JMac Feb 8 '17 at 10:55

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