Fiber chopper and method of controlling force

A chopper for separating long lengths of unwound item(s) selected from the group consisting of one or more strands comprising fibers, fiber, filament, string, yarn, wire, tape and ribbon into short segments comprising a frame, a rotatable backup roll outboard of one side of the frame, the backup roll having a peripheral working layer, a rotatable blade roll outboard of the side of the frame, the blade roll having a plurality of blades spaced apart around its periphery for contact with and penetration of said items and into the peripheral working layer and a biasing system for biasing or forcing the blades of the blade roll and the working layer of the backup roll together, the improvement comprising;

• the biasing system comprising one or more strain gauges or load cells.