Cutting, by ‘pressing and slicing,’ of thin floppy slices of materials illustrated by experiments on cheddar cheese and salami

Why it is easier to cut with even the sharpest knife when ‘pressing down and sliding’ than when merely ‘pressing down alone’ is explained. A variety of cases of cutting where the blade and workpiece have different relative motions is analysed and it is shown that the greater the ‘slice/push ratio’ ξ given by (blade speed parallel to the cutting edge/blade speed perpendicular to the cutting edge), the lower the cutting forces. However, friction limits the reductions attainable at the highest ξ. The analysis is applied to the geometry of a wheel cutting device (delicatessan slicer) and experiments with a cheddar cheese and a salami using such an instrumented device confirm the general predictions.