There seems to be no clear cut answer to this problem. There are a few adjustments you might try. Bear in mind, that it may require a combination of things to bring the slit quality up to acceptable standards.
- Reposition the slitter’s mounting dovetail bar to insure that the slit edge is supported as it is being cut.
- Set the surface speed of the lower slitter rings to as much as 5% over speed relative to the line speed.
- Use a larger ring diameter on the bottom slitters relative to the upper slitter knife’s ring diameter, as much as 6 to 8 inches (150 – 200 mm)
- Try less penetration when setting the top slitter blade. One slitter manufacturer recommends approximately a 0.015″ (2 mm) total overlap between upper and lower slitter points.
- Minimize wrap over the bottom slitter rings which will reduce penetration of the lower ring into the web path. Position the lead in roll prior to the slitter to permit no more than 0.015″ (2 mm) penetration.
- Add a support ring on the outboard bottom slitter. This supports the edge trim and prevents tearing as the trim removal system pulls the trim edge away. The support ring diameter should match the bottom slitter ring diameter.
