High Speed Roll Slitting Rewinding Machine

High speed kraft paper slitting rewinding machine

The process involves two main functions:

1. Slitting: Cutting the wide web of paper longitudinally into multiple strips of desired width.

2. Rewinding: Re-rolling these strips onto new cores with the correct tension, hardness, and edge alignment for optimal performance on downstream equipment.

Key Components & Process Flow

A typical machine follows this sequence:

1. Unwind Stand: Holds the master jumbo roll. Can be shaftless (for quick loading) or with a shaft. Often includes a braking system for tension control.

2. Web Guide System (Optional but critical for quality): Ensures the paper edge is aligned before slitting to prevent waste and ensure straight cuts.

3. Slitting Unit: The heart of the machine. Two main types:

   • Razor Blade Slitting: A sharp, stationary razor blade presses against a rubber-coated roller. Ideal for lighter-weight kraft papers (e.g., 40-100 gsm). Simple and cost-effective.

   • Shear Cut Slitting: Uses a circular top blade that contacts a bottom "anvil" blade at a precise angle. Superior for:

     • Heavier kraft papers (e.g., 100-400 gsm).

     • Multi-ply laminated kraft.

     • Producing cleaner, dust-free edges.

     • Longer blade life.

4. Spreader Bars/Rollers: Prevent the slit strips from touching and air entrapment, ensuring a tight rewind.

5. Rewind Unit: Where the new rolls are formed. Critical for controlling roll hardness. Common types:

   • Surface Rewind (Drum Rewind): Rolls are wound against a driven drum. Provides excellent tension control and consistent hardness. Best for medium-to-high speed operations.

   • Centre Rewind: Each new roll is driven independently by its own shaft/motor. Offers more flexibility for different roll diameters and materials but can be more complex.

   • Differential Rewind: A hybrid system often used for high-speed applications, allowing individual tension adjustment.

6. Shaft Puller & Unloading System: For easier removal of the finished, often heavy, rolls. Essential for operator safety and efficiency.

Types of Machines for Kraft Paper

The choice depends on production volume, paper grade, and roll specifications.

1. Two-Drum Surface Rewinder with Razor Slitter:

   • Best for: Standard, single-ply kraft (40-120 gsm), medium volumes, converting shops.

   • Pros: Robust, reliable, easy to operate, lower cost.

   • Cons: Limited to lighter weights; razor blades generate some dust.

2. Two-Drum Surface Rewinder with Shear Cut Slitter:

   • Best for: Heavy-duty kraft, multi-ply, recycled kraft, high-quality edges.

   • Pros: Clean cut, handles heavy stock, versatile.

   • Cons: Higher initial cost, blades require precise setup.

3. Centre Surface Rewinder (CSR):

   • Best for: High-speed, high-volume production (e.g., large paper mills). Often handles the widest, heaviest jumbo rolls.

   • Pros: Excellent control, can produce large finished roll diameters, high productivity.

   • Cons: Most expensive, complex.

4. Portable/Table-Top Slitter Rewinder:

   • Best for: Small businesses, sample making, very low-volume conversion of light kraft.

   • Pros: Affordable, space-saving, simple.

   • Cons: Manual operation, low speed, limited to small rolls.