Precision Rotary Slitter Knives for Film, Tape & Flexible Packaging Converting

For shear slitting of flexible films and foils, specify ±0.002 mm thickness tolerance and ≤20.02 mm T.I.R. runout. A 0.005 mm error per blade compounds across a 12-knife stack, producing visible slit-width deviation and web tension spikes. We grind every blade to these tolerances and verify on a CMM before dispatch.

Over-speed ratio is the intentional rotational speed differential between the top knife arbor and bottom anvil arbor—typically set at 2–5% above web speed. This differential creates a micro-shear action at the cut point, producing a cleaner edge and reducing heat build-up versus a purely tangential cut. At higher over-speed ratios cut quality improves but edge wear accelerates; at zero differential the blade acts more like a crush cutter. Your slitter OEM specifies the designed over-speed ratio; we supply matched pairs optimized for that setting.

Adhesive build-up on blade faces increases friction, raises web temperature, and causes material transfer contamination. We offer TiN (titanium nitride) and DLC (diamond-like carbon) PVD coatings that reduce surface adhesion by up to 80%, extending clean-running intervals on pressure-sensitive tape and adhesive laminate slitting applications.

PM steel (ASP23, ASP52) is recommended when slitting highly abrasive flexible substrates such as fiberglass-reinforced packaging films, silica-coated release liners, or ceramic-filled barrier films. These materials exceed the abrasion ceiling of D2 within a single production run due to hard mineral filler particles. PM grades deliver uniform carbide distribution and 50–80% longer edge life on highly abrasive flexible substrates.

DLC (diamond-like carbon) PVD coating is the top specification for double-coated foam tape and transfer adhesive slitting. It reduces contact angle on the blade face by approximately 35° versus uncoated D2, maintaining consistent slip through 8–12 hour production runs without cleaning stops. TiN is effective for single-faced masking tape and lightly adhesive label stock at a lower coating cost.

Yes. Matched shear pairs—dished top blade and grooved anvil bottom blade—are supplied with knife-to-knife clearance pre-verified against your substrate specification. We record OD, ID, thickness, and designed shear clearance for each matched pair on an engineering data sheet that ships with the tooling, allowing line operators to replicate the clearance setting on every reinstallation.

For meltblown and spunbond nonwoven fabrics (8–80 GSM), specify a positive rake angle (15°–20°) with Ra ≤0.4 μm surface finish. This geometry shears through the loose fiber structure cleanly without lateral fiber displacement that causes frayed edges. For very lightweight meltblown (<15 GSM), an optional ESD (electrostatic discharge) coating prevents static-induced fiber attraction to the blade face.