Shear slitting of aluminum webs using block knives

Abstract

C Shear slitting of two aluminum webs, namely 1050 H18 of 0.28 mm thick and 5182 H19 of 0.20 mm thick, using block knives are investigated through experiments using a laboratory slitter. This investigation focused on two aspects of shear slitting using block knives, appropriate for relatively thick webs. They are: (1) tangential shear slitting at zero rake angle, i.e., traditional shear slitting with a pair of block knives. In this aspect, the effects of major slitting parameters on the burr height at the slit edge were investigated. These include the clearance, overlap, overdrive and cant angle. The critical clearances for both webs have been determined; and (2) slitting at a rake angle, a new method for edge trimming when the two blades are not necessarily in contact. The top blade geometry was modified for slitting with a rake angle of -15o to allow slitting of an aluminum web, up to 1 mm thick in this investigation. This new method of edge trimming using block knives was found to be very effective and robust over a (relatively) very wide range of slitting parameters. Very good slit edge was produced, and the burr height was found to be independent of slitting parameters over a relatively large range of slitting parameters. Because two blades do not have to be in contact in slitting so that the blade wear is much less than in the case of traditional shear slitting, this new method is expected to extend significantly the block knife service life while producing consistently high quality slit edges.