How to manufacture a tissue machine

What is the Manufacturing Method Involved in a Tissue Machine?

The manufacturing method involved in a Tissue Machine is described below:

It starts by making a web of wood fibers further dewatered by ongoing solid content. The solid content is 0.1-0.5%. The Tissue Machine is different from paper making machine because of the length and other features like dryness, stiffness, texture, etc.

A stock solution is prepared, and raw materials are filled into the machine. The pulp passes through the headbox, forming section, press section, dryer, and hood. The pulp then comes out as a sheet cut into desired shapes and lengths.

 

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What does the Forming System of a Tissue Machine Include?

The forming system of a Tissue Machine is elaborated down below:

The headbox used in tissue making is almost the same as paper making, but the former is specifically designed for lower concentrations. It works by dividing the stock equally across the wire to get good formation.

Some turbulence is introduced in the system to prevent the climbing of the fibers and allow proper distribution. The direction or orientation of the fibers is also essential and can be controlled by the ratio of jet speed to the wire speed.

The option of forming two to three layers is available using a multilayer headbox. It helps to create different features for each layer, such as optical properties and printability.

There are four different configurations for the forming process, but crescent forming is the component and most practiced one.

 

How Does Pressing Work in a Tissue Machine?

Pressing is an essential step in making tissue paper from a Tissue Machine. It is explained as:

When the sheet is 15-20% dry, it is transferred to a felt and then the cylinder. The nip pressure has to be 2 to 4 MPa. One or two press rolls are pressed against the cylinder under the conditions. If a nip is used, one of the rolls is usually a suction roll.

However, single press roll configuration is more common in industries these days.

The pressure after the maximum nip pressure is reduced abruptly so that there is a minimum resetting of the web.

 

What is the Drying Role of a Tissue Machine?

A Tissue Machine dries the tissue after pressing, using a steam-heated cylinder that helps increase the solid content from 40-45% to 94-98%. The greater the drying need, the more significant will be the cylinder to meet the drying requirements.

The most common diameter for a cylinder is 5-6 m. The surface temperature of the cylinder is as high as 100°C. Some other functions of the drying cylinder are as follows:

  • It gives a base for the creeping process following the drying.
  • It works as a roll in the hot pressing.
  • The transport of the sheet during the drying process is also its function.

The heat source is the steam that condenses on the inner walls of the cylinder, and the condensate is collected in the headers. The cylinder is usually connected to the hood to blow hot air to the web when required.

The temperature has to be up to 550°C in the blowing process. There is also chemical spray on the cylinder to allow separation in the creping process. It also helps in increasing the surface area.

 

What Does the Creping Process of Tissue Machine Involve?

Knowing some basic terms about the process is essential to understanding creping.

● Yankee Dryer/Cylinder

It is a rotating pressure vessel with a diameter range of 14′ to 18′ and a circumference speed of 30m/s. It helps in pressing the rolls and drying the sheets and is the primary platform for creping.

● Yankee Coating

It is a naturally occurring pulp mixture of hemicellulose, lignin, and chemicals. On the Yankee face, it makes a sticky layer for helping in sheet transfer. The extent of its stickiness is determined by its adhesive strength.

● Crepe Pocket

It is a space between the Yankee surface and crepe blade tip and is the site for the creping process.

● Creep Ratio

The difference in speed between the uncreped and the creped sheet.

● Creping

During the expansion of the sheet in the Z direction, there are chances that some fibers will bend and buckle. For a short distance, the buckled and expanded sheet will release from the surface of the dryer. This step depends on the adhesive strength; the weaker it is, the longer this distance will be.

Before the re-impaction of the held sheet, a small crepe (tissue fold) is formed, and the process restarts. These folds are called crepe bars which you can see with the help of low-power microscopes. The crepe frequency is 50-120 kHz with 20-40 crepe bars per cm.

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What are the Factors Affecting Creping of a Tissue Machine?

There are different factors affecting creping of a Tissue Machine, some of which are:

● Fiber Choice and Management

The sheet undergoes two transformations: fiber bending and buckling and Z-direction H-bond disruption. Some fibers show more resistance to these transformations than others.

A mixture of softwood and hardwood fibers helps decide the sheet’s strength properties. The hydrogen bonding potential is higher in longer softwood fibers and provides stiffness and strength to the sheet. But a drawback is that it shows resistance to the creping action.

● Yankee Coating

If the coating is low adhesive and soft, it will result in coarse bulky creping with low frequency and high amplitude. This adhesive layer is highly prone to fracture. If the coating is highly adhesive and complex, it will result in fine smooth creping with high frequency and low amplitude.

Such adhesive coating has a small fracture span. If the coating is highly adhesive and soft, it will produce soft bulky creping with high amplitude and frequency. This coating has high penetration properties.

● Sheet Drying

The adhesive properties of the coating will increase if the Yankee temperature is raised. But an excessive increase in the drying temperature will make the coating hard, which is helpfully against bulky creping. So a slight increase in the temperature is best for high softness.

What is the Converting Step of a Tissue Machine?

In the converting step of a Tissue Machine, some critical processes take place, from embossing to folding and packaging. Complete or partial pressing of the piles is done for embossing tissue products.

It increases the absorbency and softness of the product. Two rubber steel rolls work simultaneously in the embossing process.

Another concept is nested embossing, where plies undergo separate embossing and are joined later. As a result, higher bulk is obtained. Foot-to-foot embossing is another advanced technique that improves the absorption of the product.

Between the piles, suction pockets are made since the highest surface pattern points are opposite each other.

Printing takes place on a separate printing press or converting line for informative or decorative purposes. Usually, a converting line can print up to four colors, whereas some can offer eight different color options. For easier separation of the sheets, perforations are made on the rolls.

Next comes the winding that decides the final product shape and involves winding the required tissue quantity onto a paper core. Later it is sealed at the tailed to prevent roll opening during handling or transportation. After winding, the rolls are cut as per the desired measurement and wrapped in paper or plastic boxes for packaging.

How to Prepare the Stock Solution for your Tissue Machine?

This machine mainly uses virgin and recycled pulps for making tissue. Pine and spruce are the primary sources of softwood pulp, while eucalyptus and birch give the hardwood pulp. A suitable pulp quantity can be used to increase tissue absorption.

Mixed wastes from newspapers and magazines can be used to make recycled pulps for making tissue. For obtaining a better quality tissue with more absorbance, chemical fibers are mainly used.

If you use virgin pulp in the tissue manufacturing process, bleaching can increase absorption and bring shine and brightness to the product. Bleaching also helps in reducing the impurities in your tissue material.

To enhance the tensile properties of tissue, you can refine your virgin pulp. The entire stock solution consists of substances that improve the characteristics of the tissue. Some of them include tinting dyes, resins, brighteners, and pigments.

To further enhance the functioning of the Tissue Machine, you can add good quality antifoaming agents and chemicals that can control the pH.

What are the Most Commonly Used Actuators for a Tissue Machine?

To support the motion of your Tissue Machine, you can add the following actuators:

● SteamPlus XP

This actuator is suitable to be installed in harsh and confined environments. It works well for controlling the moisture of various processes and provides a high drying capacity to the machine. This updated actuator controls the stream flowing across the web.

It comprises no involvement of ant unsegmented steam sections, which can decrease the sheet temperature differential. Thus, the actuator comprises a T880C pneumatic actuator that guarantees excellent operation even in corrosive environments.

● Dilution XP

This actuator is an advanced model of the standard rotary actuator technology, with easy installation, simple maintenance, and rugged design; reliability, strength, and durability are also its prominent features. You can install it to quickly recover the grade changes and technical faults in your Tissue Machine.

It features excellent and accurate positioning measurement quality with the help of a built-in positioning sensor. The best thing about this actuator is its continuous operation due to the pre-installed backup system, which can work even during setpoint changes, power supply failures, and flush cycles.

Which Drives and Motors are Suitable for your Tissue Machine?

The Tissue Machine drive PMC800 has unique and innovative technology to support the machine’s performance. Mainly, this drive has the ACS800 central unit that works excellently for drive and engineered control. Its parallel units promote continuous and trouble-free operation.

It features a bookshelf design to which plug-in connectors are attached for easier maintenance. The IGBT technology and self-diagnostics features make it a safe, advanced, and effective system. It features lower energy consumption and accessory monitors and sensors to maintain a suitable temperature even in extreme temperature variations.

To support the efficiency of your Tissue Machine, you can use IE2, IE3, and IE4 motors that comply with the Minimum Efficiency Performance Standards, NEMA, and IEC requirements.

All these motors feature high efficiency and maximum energy-saving benefits. These motors’ primary benefit is installing small motors, which can efficiently save your Tissue Machine energy consumption.

What are the Sensors Connected to a Tissue Machine?

The sensors connected to a Tissue Machine are:

  • Basis weight sensor
  • Reflection fiber weight sensor
  • Moisture sensor

 

How to Test the Pulp Quality in a Tissue Machine?

The following tests should be carried out to test the pulp quality in a Tissue Machine:

● Moisture Content

It is the difference between the weight of the oven-dried sample and the original sample.

● Consistency

It measures the concentration of dry solids in a water and fiber suspension.

● Viscosity

Viscosity is the cellulose’s polymerization degree and the extent of cellulose degradation in the bleaching and pulping process.

How to Test the Paper Production Quality of your Tissue Machine?

For testing the paper production quality of your Tissue Machine, the following tests are necessary:

● Density

It is tested by calculating the thickness and weight of the sheet in the available area.

● Tensile Strength

A paper strip is clamped between two jaws in a tensile testing machine. The resulting load is recorded with the stretch in paper to its breaking point as the jaws move.

● Tear Strength

A pendulum-type device measures the energy absorbed in tearing a paper sample.

What are the Things to Consider when Operating your Tissue Machine?

Given below are a few things that you should consider when operating your Tissue Machine:

  • It should have a compact design without any compromise on efficiency so that the batch timing is reduced.
  • The power consumption should be low so that the same quantity of fiber can be processed by using less water.
  • The essential design initiative is better patterned with refiner disks. It helps in the better development of different types of pulp and the promotion of short fiber.
  • The replacement of the mixing tank, discharge pump, and agitator with a more straightforward system is preferred.

What does Tissue Machine Optimization Involve?

Tissue Machine optimization allows for better performance with minimum efforts and energy consumption. There is a proper three-step methodology to determine the optimization requirement, implement strategies and sustain the improved performance through regular maintenance.

● Diagnosis

The first step is a diagnosis that creates a benchmark for implementing strategies for improved performance. It requires comprehensive testing and analysis to check the performance indicators and assess the improvement potential. Also, check the following:

  • Stock approach stability
  • Product variability
  • Machine response
  • Profile capability

There are exclusive tools for diagnosis and troubleshooting so that the strategy is formulated according to the given conditions.

Once the strategy has been implemented, it is essential to sustain the performance, which requires excellent maintenance skills.

How to Prevent Corrosion in your Tissue Machine?

To prevent corrosion in your Tissue Machine, you can follow the given steps:

  • Add to the layering of the machine with the help of polarization.
  • You can use adhesive paint or any other quality adhesive to prevent direct contact of the machine with the environment.
  • The environment should be clear from humidity, and no moisture should be allowed near the machine.
  • There is an option of an anti-corrosion adhesive layer.
  • The best option is galvanizing. It is a method in which a more stable metallic ion covers the metallic surface to act as a barrier against the oxidation process.
  • The body should be made of high-quality stainless steel, resistant to corrosion.

Conclusion.

A Tissue Machine uses air-dry technology for tissue production with safe bleaching and de-inking agents. No chlorine gas or alkyl phenol exothylaye derivatives are used. The final product is wrapped in the stretch film and shipped on pellets. The packaging process is fully automatic and uses robotic technology.

Our energy-saving and wide production Tissue Machine varieties provide optimized performance throughout their prolonged service life. There is incredible complexity in converting raw wood into tissue paper, requiring multiple raw materials for high-quality production.

We maintain the quality of raw materials so that the final products you get are matchless in terms of quality and durability. For further details, contact our online customer care service.

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