With the improvement of living standards and technological advancements, the requirements for flexible packaging products have become increasingly stringent.
Films now demand lower elongation rates, and the neatness of the winding end faces must be higher. These requirements impose stricter standards on the tension control of film materials.The tension control accuracy of the rewinding shaft directly determines the elongation rate and the neatness of the slit products, making it necessary to use a differential shaft.
The use of differential friction shafts improves the speed, rewinding precision, automation, preparation time reduction, and user-friendliness of slitting rewinding machines.
This is particularly beneficial for materials with poor tensile properties and significant thickness variations, such as cast polyester films, as the use of a differential shaft reduces winding difficulty. For valuable materials like carbon fiber pre-preg, differential shaft rewinding significantly improves product quality and reduces production costs.
Differential shafts are generally used as rewinding shafts for slitter rewinder. Their purpose is to maintain constant tension during rewinding by utilizing the sliding principle of each slip ring on the shaft.
The unique structure of the differential shaft, consisting of multiple friction slip rings, effectively addresses the above challenges. During operation, the slip rings are controlled to slip at a specific sliding torque value, compensating for the speed differences and precisely controlling the tension of each roll of material, thereby achieving constant tension winding and ensuring winding quality.
Differential shafts are mainly categorized into center pneumatic and side pressure types. Both types rely on the slip ring’s sliding function, which allows multiple rolls of material to be wound simultaneously on a single shaft.
Due to uneven material thickness, some rolls may be loose, and others tight. The tight rolls will slip to relieve tension, achieving the desired winding effect. By adjusting the air pressure, the tension on the shaft can be regulated to maintain a stable value.
When the wound material is too tight, the slip rings will slip against the shaft core, reaching an optimal tightness. This tension is directly related to air pressure. Modern slitting machines typically feature an air pressure system that automatically increases tension as the roll diameter grows. In the absence of such a system, manual adjustment is required, necessitating experienced operators to adjust during machine operation.
The use of differential shafts improves slitting machine speed, rewinding precision, automation, preparation time reduction, and user-friendliness, particularly for films with poor tensile properties and significant thickness variations.
The difficulty of winding such materials is reduced. For precious materials like prepreg, applying a differential shaft significantly enhances the product yield and reduces production costs. This technology was initially used for specialty papers.
Why differential friction shaft is expensive?
The high cost of differential shafts is primarily due to the complex and technically advanced engineering involved in their design and manufacture.
The main functionalities of a differential shaft include regulating material tension at varying speeds to ensure constant tension during winding or unwinding, which is critical for applications requiring high-precision material handling. Key factors contributing to the cost include:
- Structural Design:
Differential shafts typically consist of a core, friction components, and multiple slip rings. These components require high-precision machining and assembly to ensure performance, increasing production costs. - Material Selection:
High-quality materials are often used in manufacturing differential shafts, especially in friction components, to provide stable frictional force, adding to the cost. - Technical Complexity:
The performance of a differential shaft relies on pneumatic pressure to regulate friction torque, requiring precise air pressure control systems. The advanced and complex technology increases production difficulty and cost. - Maintenance Requirements:
Due to their high precision and complexity, differential shafts may require specialized knowledge and skills for maintenance and troubleshooting, potentially leading to additional maintenance costs.
In summary, the high cost of differential shafts arises from their precise design, high-quality materials, technical complexity, and specialized maintenance needs. When deciding whether to use a differential shaft, it is essential to consider cost-effectiveness and production requirements.
Why my differential friction shaft is so hot ?
Common issues with differential shafts include overloading, improper maintenance, and challenging operating environments.
Prolonged operation under overload conditions can deform or break the shaft core, disrupting normal operation and generating excessive heat. Improper maintenance, such as neglecting regular cleaning, can cause components like slip rings, airbags, and friction parts to accumulate dust, paper scraps, or other debris, which affects lubrication and heat dissipation, leading to overheating.
Additionally, high humidity or the presence of metal debris in the working environment may hinder effective heat dissipation, further contributing to excessive heat generation in differential shafts.
To address the issue of excessive heat generation in differential friction shafts during rewinding, we have developed an innovative water-cooling system integrated into the shaft. This system operates with an inlet and outlet cycle for cooling water, effectively dissipating heat during the rewinding process and preventing damage to critical components, such as the airbag.
This solution is a patented technology designed specifically for the high-precision slitting and rewinding of advanced composite prepreg materials.
Last Updated on 03/07/2025 by Jota Machinery