Tissue

The next step is the Formation -

If you are looking for more details, kindly visit our website.

From a layman&#;s perspective if I see a sheet with a patchy sheet formation and with pinholes amongst others, I would be reluctant to buy the product a second time. Needless to say it would also be really hard to run on the converting machine and the functionality of the paper would be low. So the Formation is very critical! The formation in modern day machines happens using a roll former! In the past this used to take place using a plain breast roll on a fourdrinier section, moved on to a Suction breast roll, on to a twin wire former or a roll forming concept. The main difference in the same was:

Fourdrinier Machines

Twin Wire Machines

Most used in the 60&#;s and 70&#;s

Used from the 70&#;s till date

Difficult to operate

Easy to operate

High tensile ratio &#; Since these machines were based on the fourdrinier concept these machines had a very high MD tensile strength

Improved sheet quality

Speed limitations of &#; m/min

No speed limitations at the wet end of the machine. The limitations come on the drying end.

A beautiful video by the PaperClassroom on formation please see the below clip:

Moving on the twin wire concept there are three different concepts:

1. S &#; wrap
2. C &#; wrap
3. Crescent Former

Crescent former is the most common forming roll type used as the forming happens directly on the felt, the machine length is much shorter as well as it is cheaper and easier to use, resulting in a better product! The crescent former has many other benefits in terms of energy, transfers and machine parts requirements amongst others.

The main objective in the former is to achieve:

1. The obvious first: a good formation
2. Drainage to be uniform across the deckle
3. Able to transfer the sheet to the press section without any fiber loss

If your formation at the wet end is not even or good, you will have issues downstream in multiple avenues:

1. Poor formation leads to poor down stream fiber formation resulting in low drainage and also drying would be uneven
2. Creping will be effected
3. There will be compromises in the strength and softness of the tissue!

Formation can be influenced by a variety of factors including the types of fibers used and the consistency of the fibers. As covered in the refining section, formation is greatly affected by the refining. However if you over refine the fibers, the fibers might not bond, resulting in formation issues. The headbox design and flow rate, can also effect the formation along with the drainage length and the wet end chemistry.

Mingyang Machinery supply professional and honest service.

The principal in brief:

As the pulp slurry falls on the fabric from the water jets within the head-box, the breast roll uses a forming fabric to press the slurry against the felt, avoiding the need to transfer the paper to a felt later in the process. The initial drainage takes place at this stage around the forming roll, with the wire tension determining the amount of the drainage. The pressure at the forming roll is calculated as under:

The most common forming roll diameter is 1.5 meters, and the same is sufficient to make tissue up to 40 GSM. However the machine slows down on heavy weights as the drainage pressure needs to be increased and hence retain higher tension. The machine generally functions at m/min, and on the middle basis weights from 13 &#; 2 GSM the machine attains its design speed of m/min. The drainage pressure is important because if the paper is not dewatered at the initial stage, we might need to use more energy at the Yankee to achieve a finished moisture content of 5-6%! The same can also effect the inter fiber bonding and other properties.

The jet speed from the headbox to the felt and the speed of the machine also influences the properties of the paper primarily influencing the tension in the paper.

Now that you know how the formation of the paper begins, it&#;s a good time to talk about the deckles and trim. The common finished paper deckles in the industry are mm, mm and mm. Whilst there are a range of other sizes these are the most common sizes!

A deckle is the breadth of the web across which the paper is made on the forming roll whilst the trims, are the excess that are cut during the manufacturing process to ensure quality of the finished product and to reuse the same in the fiber input line!

We generally have three widths on a paper machine:

1. Wire Width: The entire width of the felt fabric covering the forming roll. The same is generally greater than the headbox width
2. Web Width: The width on which the fibers fall on the felt from the headbox. As pulp is a slurry the web width is also slightly greater than the width of the head box
3. Trimmed Width: The edges on the web are trimmed in the wet end, as by principal the bonding is not expected to be the best and the paper will be weak and will be of no use. In order to not expel energy to dry the trim and later trim in the dry end, a part of the web is trimmed. The remaining deckle of the paper is what is consumable. Although the paper is again trimmed in the dry end, either during converting or during the rewinding process.

Let us take the example of a finished machine deckle of MM to explain the widths better:

1. The headbox of the machine would be designed at mm
2. The Wire Width would be mm
3. The Paper Width on the wire would be mm
4. The trim on the forming roll would be 54.5 mm on either side
5. The trimmed width or usable part of the paper would be mm with 3mm would be uneven from the trim at the forming roll

This vastly completes the wet end of the paper. The paper is then carried from the wet end on the felt to the press section. The press section transfers the paper from the felt to the yankee for the final stage of drying. The press section is also a cheaper method to drain water from the sheet rather than using energy to further dry the paper.

Efficiency and waste reduction are crucial aspects of the tissue and paper-converting industry. While waste is an inevitable part of the converting process, there are various strategies and technologies that can be employed to minimize waste and optimize operations. In this article, we will explore the importance of waste optimization, the obstacles faced in the industry, and the opportunities for improvement through automation. By implementing effective waste automation techniques, paper converters can enhance productivity, reduce costs, and improve overall sustainability.

MINIMIZING WASTE: A NECESSARY EVIL

When converting paper products, the focus is primarily on maximizing production throughput and minimizing waste. However, it is essential to recognize that waste is an inherent part of the process. No matter how well waste is minimized, the more production that takes place, the more waste is generated. Often, the waste stream needs to be noticed amidst the optimization efforts in the facility. To address this issue, it is crucial to find ways to optimize without compromising production efficiency.

OBSTACLES AND OPPORTUNITIES FOR EFFICIENCY IMPROVEMENT

Manual labor poses significant challenges to efficiency, especially in the current labor market conditions. Finding and retaining skilled employees is increasingly more difficult, leading to staffing shortages and potential inefficiencies. On the other hand, automated machinery offers greater reliability and consistent performance. By automating various processes, manufacturers can reduce dependence on manual labor, free up floor space, and minimize safety risks associated with human error.

TYPES OF WASTE AND AUTOMATION TECHNIQUES

To effectively optimize the waste stream, it is essential to identify the different types of waste produced in the paper product converting process. These include slab waste (both prior to unwinding and spent rolls), log waste, roll, and trim waste. Streamlining the process by automating material transport can significantly contribute to waste reduction. Implementing shredders is a common approach to transforming waste materials into a more manageable and consistent form for further processing. Shredders can be strategically placed offline near unwinders to ensure minimal impact on uptime. Additionally, shredders can be installed online to handle log waste, roll waste, and trim waste (as it is discharged from the converting equipment), allowing for immediate disposal and transportation.

THE HIGHWAY IN THE SKY: CONTAINING WASTE AND DUST

One crucial aspect of waste automation is the implementation of a comprehensive air system; we like to call it the &#;Highway in the Sky.&#; The system includes ducting, fans, blowers, and filters to contain waste and dust particles generated during the converting process. This process facilitates the transportation of waste materials back to the pulper or other designated areas for recycling or disposal. By effectively containing waste, dust is collected, allowing converters to prevent its accumulation throughout the facility, reducing the risk of fires and improving overall air quality.

REAL-LIFE EXAMPLE AND ECONOMIC CONSIDERATIONS

Let&#;s examine a hypothetical scenario to understand the economic impact of waste automation. Suppose a greenfield paper converting facility installs waste automation during an expansion project to install three new converting lines consisting of shredders, an air system, and other associated equipment.

The total installed cost of such a system may initially seem substantial, but the long-term cost savings justify the investment. By reducing the number of employees required for waste handling, the facility can save significant labor costs annually. Additionally, the reduction in forklifts and bins further contributes to cost savings. Considering the internal rate of return (IRR) and payback period, it becomes evident that the investment in waste automation technology pays off within a relatively short time frame.

SAFETY AND ENVIRONMENTAL BENEFITS

Automating waste handling and containing dust not only improves efficiency, but also enhances safety within the facility. By minimizing movement on the floor and reducing the risks associated with manual labor and forklift operations, converters can prevent workplace injuries and accidents. Moreover, effective waste automation practices reduce the fuel source for potential fires, and installing fire suppression equipment in the ducting system further enhances safety measures. When organizations invest in safety and reduce accidents, they also reduce liability, human suffering, and, ultimately, money. Accidents cost an average of $95,000 per accident. By that calculation alone, the reduction in time to pay back for implementing automation and optimization efforts shortens significantly.

THE KIND OF POSITIVE IMPACT YOU MIGHT BE LOOKING FOR

Automating waste management in the paper industry significantly benefits facility operations and safety, and is a true cost reduction project. By using automated systems like shredders and efficient waste transport, paper converters can minimize manual labor, streamline processes, and optimize production efficiency. The advantages include improved plant safety, increased worker productivity, and reduced operational costs. Automation allows operators to focus on core tasks, leading to higher production output and a safer work environment. It eliminates manual labor expenses, reduces reliance on equipment, and lowers maintenance costs, resulting in substantial financial savings.

Additionally, automated waste management systems address safety concerns by reducing injuries, mitigating fire risks, and controlling dust accumulation. Dust containment within shredders and air systems minimizes fire fuel sources and enhances facility safety. These systems can be tailored to fit existing or new production lines, adapting to specific processes and materials for maximum efficiency. Embracing automation in waste management enables the paper industry to improve productivity, profitability, and sustainability, ensuring the efficient use of resources and contributing to industry advancement.

The company is the world’s best Tissue Production System supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.