How does a garden chipper or shredder work?

Generally speaking, you feed the organic material into an opening at the top of the machine (the hopper) and, depending on the type of shredder you have purchased, it will break the material down, shredding it either with rotating blades, or cogs or blades and flail hammers, usually pulling the material through and distributing it from the bottom of the machine as fine, broken down particles. (see image below for basic function)

 

 

As you can see, the left chipper/shredder is handling leaves, while the right is dealing with twigs/braches.

 

It is worth noting that the finer the end product, the quicker and more easily it breaks down into compost.