Effect of anvil position on cutting force and energy measurements of a disc chipper

Abstract

Using renewable energy as wood chip or improving wood chip heating process are different usual ways to reduce carbon dioxide emission. The more uncharted path to reduce it is to limit energy consumed to produce wood-based fuel as wood chips or pellets. Wood chipping is the first step of each wood fuel production process. Chipping wood knowledge is also important for improving wood chipper efficiency. This paper compares two methods for determining cutting energy of a disc chipper and evaluates influence of anvil position on chipper efficiency.Cutting force is measured by the anvil bending during chipping and disc chipper energy supply is calculated by multiply the torque applied by the Power Take Off (PTO) to the shaft of the chipper by the shaft speed. In our study, a large set of chipping conditions are tested on a disc chipper with different species, log diameters, infeed volume rates and anvil vertical position.Cutting force measured from anvil's strain represents one impact for each half disc turn because the disc has two knives, whereas chipper energy supply is similar to a sinus curve. Cutting force depends of wood specie, diameter, infeed volume rates and anvil vertical position. Higher the wood infeed volume rate and diameter are, higher the cutting forces are. A disc chipper efficiency is estimated as the ratio of the cutting energy and the chipper energy supply.