The value in making cone liners with an increased feed opening is not about allowing for greater reduction ratios, but about insuring that the liner set provides a consistent output rate through full expenditure.

The concept is to remove steel where it’s not needed (at the feed end) and apply the wear steel where it is needed (at the discharge end). Most cone liners are removed when the feed opening closes off enough to reduce the output rate. A proper feed opening dimension that is in ratio with the thickness of the bowl and mantle, with proper feed size, will wear to full expenditure while maintaining a constant output rate.

Increasing the feed opening and thickness of cone parts takes considerable care in order to minimally affect the included angle between the liners, and not cause an adverse reaction to the size of feed material. Each category of crushing cavity -- fine, medium and coarse -- requires its own ratio of feed opening to length and thickness. In some cases, these categories of crushing are split even more finitely. This subject is closely related to determining the optimum feed size for a particular set of liners.