Chipping v Shredding
Whilst chipping and shredding are often used interchangeably when discussing green waste disposal, the truth is that they are two very different processes that once understood can be extremely helpful in ensuring you use the correct machine for the jobs you have.
Chipping generally involves a sharp hardened metal blade fixed onto a large metal flywheel that is rotated at high speeds. The rotating blade is positioned close to a fixed metal anvil and together they create the slice of wood or chip as branches are fed into the infeed chute. This standard chipping method is designed for chipping hard wood and relies upon the wood be of certain strength to allow the chipping blade to be effective. Wet leaves for example are not suitable to try and chip.
Shredders use a different process to chippers, that being free swinging knives or hammers located on a central shaft rotating at high speeds that pulverize anything that is dropped into them. The knives will come into contact with the material several times as they spin and will efficiently break down all types of green waste. Unlike chippers, shredders are not damaged should grit, stones or even nails be dropped into them as they will be able to pass through the machine without hindrance. Shredders are designed for the reduction in size of large volumes of green waste.
A significant difference between chippers and shredders is the amount of power required for each process. Chipping is an efficient process that relative to shredding requires far less engine power. For example a 4” chipper can be made using a 13hp engine, however a 4” shredder would need in the order of 35hp! This is simply because of the momentum that is required to keep the shredding rotor turning quickly when material is being put into it.