What is rewinder in paper machine?

A rewinder plays a crucial role in the production process of various materials such as paper, film, or tape. Its primary function is to re-roll these materials into smaller rolls or specific configurations. There exists a variety of rewinder machines, including surface winders, center winders, and coreless winders, each designed to perform this task with its unique operational characteristics.

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The typical structure of a rewinder encompasses several rollers or drums through which the material is guided. Additionally, a drive system is integrated to facilitate the rotation of these components, effectively winding the material onto a spindle or core. Some advanced models also incorporate slitting or cutting mechanisms, allowing for tailored lengths and widths of the final product.

The operation of a rewinder is generally straightforward. The operator places the material onto the machine and configures the desired settings such as winding speed, material width, and the dimensions of the finished roll. Subsequently, the machine utilizes its drive system and rollers to manage the material's tension and alignment as it winds onto the core. Once the winding process concludes, the finished roll can be detached for further use or storage.

Rewinder Machines Explained

In the realm of papermaking, rewinder machines are vital for transforming the paper web, sourced from the main machine reel, into manageable rolls of designated sizes. The winding segment of the machine comprises a duo of rolls, each equipped with its independent drive system.

Design Features

The rewinder is engineered for both rewinding and longitudinal slitting, ensuring the output paper rolls adhere to specific size requirements. Notably, the winding apparatus consists of two rolls, each of which is driven independently. It features a hydraulically controlled system for ejecting the finished rolls, along with a cross cutter that separates the paper from the wound roll, integrated into the first rolling position aligned with the paper web’s flow. The second roll also follows a similar design but utilizes pneumatic control for enhanced safety during roll handling between the tilting table and the supporting roll. Both rolls are balanced dynamically based on the prescribed winding speed, with their surfaces treated through plasma spraying. The operation is managed by variable-speed AC motors, and the rolls are laterally aligned by mandrels that can be pneumatically adjusted. As the paper rolls are formed, a rider roll presses down from above, with its tension modified according to the developing roll's diameter. Once at the uppermost position, the rider roll locks into place.

Core Components

• bearing structure - individual stands forged from profile steel, secured together with bolts and locks (1)

• supporting rolls (2)

• pressure roll (3)

• core clamping mandrels (4)

• paper rolls ejector (5)

• tilting table (6)

• spreader rolls (7)

• slitting section (8)

• paper web threading (9)

• unwinding stand (10)

• machine hydrostatic drive

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• machine pneumatic circuit

• machine electric parts (including switchboard boxes and control boards)

• control system including software

• machine guards

• machine drive (11)

Slitting Section Analysis

This section is designed based on the desired strip widths, maximum operational speeds, and specific attributes of the paper web. It can be controlled pneumatically or electro-pneumatically and employs shears slitting principles either tangentially or through a slitting roll. Integrated with the slitting section are spreader rolls, essential for accurate guiding and cross-stretching of the paper web before and during the cutting process. These rolls are adjustable for optimal web running conditions. Furthermore, a direct measuring device assesses the tension of the paper web on the guiding roll to ensure proper tension management during winding. To maintain cleanliness, the slitting section is equipped with a dust extraction system that reduces surface impurities on the paper.

Paper Web Threading Overview

The threading system efficiently transfers the paper web from the unwinding stand through several rollers and sections until it reaches the rewinder's carrying rolls. This system integrates V-belt conveyors, chutes, air nozzles, and clamping devices, along with an under-pressure mechanism that affixes the web onto the first carrying roll of the rewinder.

Unwinding Stand Specifications

Engineered as a twin-frame setup, the unwinding stand comprises two positions complete with reel spool beds, locking levers, and ejectors for empty reels, paired with hydraulic dampers for unloading operations. Unwinding can be facilitated by various braking mechanisms including AC generator motors, pneumatic disc brakes with cooling options, or drum brakes. A clutch between the brake and the reel spool is designed for pneumatic adjustment based on the carrier's dimensions. This entire component is structured with both cross and longitudinal feeds to guarantee smooth paper web entry into the machine.

The machine can also be supplied with a comprehensive electric setup, inclusive of the control systems and an automatic web threading function. Dust extraction systems and trimmings suction for the slitting section are also available. Alongside the fabrication of new machines, we also offer extensive overhaul services for existing rewinders.

Benefits of Rewinders

• Attractive price-to-productivity ratio

• High quality of rewound paper rolls

• Exceptional slitting precision

• Reliability in operational performance

Delivery Scope

• Comprehensive machine specifications as detailed

• Optional accessories

Material Composition

• bearing structures crafted from standard steel

• Roll surfaces composed of regular steel subjected to surface treatments

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