Precise Head Fit Prevents Uneven Loading and Excess Cover Wear

摘要

The precision of the fit between the network of machine components is critical to the success of a papermaking operation. Nowhere is this more clearly illustrated than at the head fit - the interface between the head and shell. Head fits are one of the most misunderstood concepts for a successful roll repair program. Two thousandths of an inch (.050mm) could be the difference between a good press fit and a loose fit. Many years ago, most plain press and suction rolls had straight head and shell fits and relied on an interference fit. This meant that the head was larger than the mating shell.