A wavy edge on the slit side of sheets, suggest the bottom slitter rings may have a slight wobble. It could be the slitter rings or it could be the condition of the bottom slitter shaft.
First, make sure the inside diameter of the bottom slitter ring is sized properly for the shaft so that there is a slide fit. Typically a clearance of 0.002” (0.05 mm) is sufficient; anymore could induce a wobble. Either the shaft is undersized or (more likely) the inside diameter of the slitter ring is oversized.
Next, check the face of the slitter ring edge for parallelism to the ground bottom slitter shaft. Using a dial indicator, the cutting face should vary no more than 0.003” (0.07 mm); otherwise the slit edge will weave accordingly within the stacked pile. Variations greater than 0.010” (0.25 mm) can be easily remedied by regrinding to a better tolerance.
Over time, steel slitter shafts can become ‘dimpled’ by slitter ring set screws that secure the rings’ positions. When positioning a slitter ring over a deformed area, be mindful that the deformation may ‘tilt’ the ring.
For deviations of less than 0.010” (0.25 mm) run out on slitter rings that are locked into position to the shaft by a set screw, drill and tap a second set screw location 120 degrees from the first. Through a combination of loosening and tightening the two set screws, you should be able to minimize the wobble and bring the slit edge into conformance.
By the way, wide 2” (76 mm) or wider slitter rings are less disposed to wobble than narrow rings.
