In the pursuit of advanced slitter rewinders, innovations have taken two extreme development directions. One approach focuses on achieving maximum technical specifications emphasising the widest width and highest speed possible. Slitter rewinders with these higher specifications are commonly employed in production lines for films and nonwoven fabrics. For instance, Nicely’s model EG-8003 series boasts an impressive 8-metre web width, making it the slitter rewinder with the widest width in Taiwan for BOPP film production.
The other extreme pursues fine narrow slitting, often referred to as ultra-fine narrow slitting. This precise slitting technique finds applications in manufacturing precision components for packaging circuit boards, microchip carriers, anti-counterfeit security threads, and electrical insulation materials. Customer requirements have steadily shifted from 4mm and 2mm narrow slitting to even finer widths, reaching 1mm or below micro slitting.
Winding techniques for narrow slits
Pancake roll
Flat-wound rolls, also known as pancake rolls, are a common form of the final product after slitting. This winding technique is suitable for 99% of slitting specifications and, if appropriate tension properties are maintained in the material, can achieve excellent winding results with good roll density and a smooth surface.
Spool roll
When the slit width is 4mm or below, the pancake technique often encounters several challenges, even with excellent tension control. Limited rewind diameters become a constraint, directly impacting the total length of the product. To address this issue, the solution lies in adopting a transverse winding approach. Generally, the basic specifications for spooled end products include:
- Min. slit width: 2mm
- Max. traverse length: 300mm
- Max. rewind diameter: 450mm
By configuring the spooling mode and setting the traverse width, the total length of spooled products is more than 20 times greater than that of pancake winding under the same outer diameter requirement. This not only significantly enhances length output capacity but also reduces downtime. Basically, any process that continuously utilises narrow-width tape will gain advantages from using a spooled product.
What makes the Nicely Spool Slitter Rewinder stand out in the field of spool slitting machines?
According to the manufacturer, a broad range of customer applications across industries can be serviced with Nicely’s spool slitter rewinder, represented by the EG-9000 series. It finds extensive applications across various industries with notable examples in:
Packaging materials
Common materials include OPP, CPP, BOPP, PET or metallic foils with surface treatment as attention-grabbing labels, available in adhesive or non-adhesive variations.
In the application of security labels as an added layer of protection against counterfeiting, holographic film with a slit width of 1mm or 2mm is commonly integrated into tobacco packaging, banknotes, and security documents. It plays a supporting role in providing security and authentication features.
Electrical insulation
It can be used for composite materials like mica tape backed with adhesive glass fibre or PE (polyethylene).
Mica tape, known for its high dielectric strength, is crucial for withstanding high voltages and temperatures, serving as insulation coil material in electric motors and generators within the electrical industry. For low-voltage applications, materials such as PI (polyimide), PE, or other thin films with low dielectric constants are used as effective insulation mediums.
Textile applications
Nonwoven fabrics are undergoing a surge in innovation, not only for medical or hygienic personal care, acting as moisture barrier (TPU) in textiles, but also serving as lightweight alternatives to various insulating materials in the thriving aeronautics and automotive industries.
Diverse configurations of the mechanism
With over 40 years of experience in the industry, Nicely has developed in-house expertise in all aspects of the unwinding / slitting / rewinding process. According to the manufacturer,”We understand that our customers work with a wide range of materials and require a flexible production approach.”
To address this need, Nicely has developed a modular spooling winder that can integrate seamlessly with Nicely’s other slitter models to produce pancake rolls and spools in one package. Thanks to the independent modular spooling system, it provides the possibility to be integrated with customers’ existing slitters.
Precision tension control – A crucial factor in spooling
Several critical factors must be considered during the delicate process of spooling, including the material thickness, tensile strength, and whether the material is a composite with a backing. All these factors can impact the tension matching of the equipment. Lower tension than pancake rolls is typically required in the winding process. As layers of material are stacked during the winding process, precise tension adjustment becomes especially crucial for fragile materials. Therefore, the winding and spooling process generally adopts a decreasing tension configuration, which differs from the fixed tension configuration used in pancake rolls. Excessive tension can lead to product deformation or material breakage.
Nicely’s strategy: “To achieve accurate tension control, we calculate the appropriate torque range to allow the winding end to provide optimal feedback based on the actual material performance. Finally, through contact with the finished product by contact rollers, precise tension control is achieved, ensuring stable production of the product.”
Spool patterns
- Pancake
- Step
- Level
- Taper
- Flanged
The spooling pattern refers to how the slit strip travels on the winding core and the final shape of the wound product during the winding process. Depending on the material characteristics and the downstream de-spooling requirements, several properties need to be specified:
- Traverse widths / angles / times.
- Overlap volume (mm).
- Gap between the next strip position (mm).
- Edge setting (mm).
There are various settings associated with different types of spool patterns, and it is necessary to evaluate the material being processed and the intended purpose before choosing the spool configuration.
The advantages of spooling
While spooling may not be the sole solution to every challenge associated with narrow-width winding, it can significantly bring the following advantages:
- Increased productivity: One of the major benefits of spooling is its ability to significantly increase the length of the final product. For many narrow-width materials, achieving the required material length without adopting this technology is nearly impossible.
- Reduced machine downtime: Additionally, spooling helps minimise downtime, effectively improving overall efficiency.
- Enhanced roll durability: When unloading the final product, spooled configurations offer higher density compared to flat-wound rolls. This eliminates concerns about material falling off from the core, providing greater convenience for downstream processes.
- Easy use for downstream applications: The spooled form of the final product proves to be more user-friendly for subsequent manufacturing processes.
Mastering versatility and efficiency in narrow slitting
The narrow slitting technology of Nicely’s slitter rewinder is widely applied across various fields, including precision packaging, anti-counterfeit labels, electrical insulation, aerospace textiles, and more. The EG-9000 series of spooling machines not only demonstrates maturity in fine slitting but also offers flexibility by integrating with different types of unwinding units. This capability allows it to meet the demands of both pancake roll slitting and fine slit spooling, achieving higher production efficiency and increased equipment versatility.