Disk chippers consist of a large diameter steel disk, generally set either at right angles to the direction of feed, or at an angle, that incorporates one or more hardened chopping blades, each with an associated slot in the disk.
 
The disk rotates at high speed and the blade cuts regular chips from the end of the biomass as it is fed in, usually by a ridged roller system. A fixed steel anvil or knife in the throat of the chipper forms the opposing cutting edge.  The knives may be set radially on the disk, or at a slight offset.  They are usually straight, but may be curved.

On the back face of the disk there may be paddles to generate airflow to eject the chips and they may incorporate serrations to act as sliver breakers to attempt to prevent the ejection of long slivers.

The size of chip produced by most disk chippers is principally determined by the number of knives and their settings, by the rotational speed of the disk and the material feed speed, which is usually determined by the feed roller speed. Varying these parameters or removing one or more blades in a multi-blade unit and blanking off the associated slot allows chip dimensions to be adjusted.

Some disk chipper can have difficulties with thin, whippy material especially when it is fed in at a slight angle, as this can lead to to the material being torn rather than cut cleanly, producing long slivers which can cause bridging in fuel feed systems.

Blades are replaceable and can generally be resharpened.

Blades can be blunted or damaged by dirt, grit, inclusions, ice or frozen timber, and in high throughput situations can require sharpening or replacing more than once a day.  Blunt blades can lead to irregular chip sizes, more slivers and greater power requirements.  It is highly advisable to ensure a supply of spare blades so that they can quickly be replaced as required and sharpened at convenience.

One design uses circular blades that can be rotated when one section becomes blunt to allow a new, sharp face to be presented.