TAD On-Line is just-in-time

Sometimes technologies advancing in different directions, for different reasons, meet to create something that is better than anyone could have expected. Such is the case with the new TAD On-Line concept for cost-effective TAD production.

Hugh O’Brian

The Merriam-Webster dictionary defines the word innovation as follows: Main Entry: in·no·va·tion. Function: noun. 1: the introduction of something new. 2: a new idea, method, or device. Synonym: NOVELTY.

It is word commonly used when new technologies are introduced but it is not so often that one looks behind the scenes to try to understand what is driving the innovation.

In a recent project jointly undertaken between Metso Paper Karlstad of Sweden and Fabio Perini S.p.A. of Italy, several driving forces for innovation were identified. They are:

- Experience acquired through many years of manufacturing machines

- Internal striving for continuous improvement

- Learning from the past and setting new aims

- Enthusiasm for new ideas

- Courage to overcome current limits and barriers


Looking more specifically at the TAD (Through-Air-Dried) tissue business, in recent months two technological developments which were independently underway in these individual companies have been brought together to create something that is clearly greater than the sum of its parts.

Over the past year, Metso Paper has been developing what it terms a “small but cost effective” TAD paper machine, which would be on a smaller scale than the full size machines that it normally builds. A world leader in making big, fast machines capable of producing the highest quality soft TAD tissue, Metso wanted to add a new machine to its product line which entailed lower capital cost and lower annual tonnage. This would in turn mean lower risk and exposure to the company installing such a TAD machine. At the same time, Fabio Perini S.p.A. had just launched a new, faster, more advanced tissue converting line. When, through the encouragement given by the European Tissue Symposium, the two companies started discussing how the two concepts might be tied together, an entirely new solution emerged. Here we will give a short background on the project and some of the results of the combined study.


“Essentially,” says Ingemar Myrén, vice president - tissue business lines at Metso Paper Karlstad, “we had been working on a new concept in which we could combine cost-effective production with the most sophisticated tissue quality. The idea was to build a smaller, simpler TAD machine which would not sacrifice anything in terms of quality.”

“In this way, a tissue company could install such a machine to introduce 30,000 tonnes per year to the market rather than 65,000 tonnes, which is what a full size machine will make. Thus the risk of building such a machine would be much lower both in terms of the capital investment, as well as the additional tonnage to be placed on the market.” The new 2.7-m wide TAD machine is called the TAD 100, with the “100” standing for a production of approximately 100 tonnes per day, as well as 100 inch trim width (Figure on p. 68-69).

The new design is based on some new, proprietary technology that Metso had developed specifically for a smaller size TAD machine. In addition, the machine was also engineered for a design speed of 1,250 m/min with, says Myrén, “no extra capacity and associated extra costs.” With the big, advanced 5.4 m wide TAD machines, there is generally a start-up curve over several years to achieve the stated tonnage. With the new design the aim is to provide a fairly basic machine that will start-up and run at 1,200 m/min very soon after start-up.

Continues Myrén, “Our idea is to build a machine that fits well with the market needs for TAD. With a capacity of 30,000 tonnes per year, the small line is designed for a very steep utilization curve. This compares with a larger 65,000 tonne per year line which, for market reasons as TAD is being introduced, may start at only 50% utilization and then ramp up to full capacity in four years.”


At the same time that Metso was developing its smaller TAD concept, Fabio Perini S.p.A. was doing something totally different: Working on the world’s fastest, most advanced tissue converting line, the Sincro LX.

Guido Finocckì, sales and marketing director at Fabio Perini S.p.A., explains: “The LX is a complete makeover of the Sincro concept, based on 10 years of experience since the first Sincro was introduced. Using our experience and knowledge, we sought to incorporate state-of-the-art innovations in every part of the converting line.”

Without going into all of the technical details of the new LX, the important result was that the speed of the converting line increased dramatically as a result of the incorporation of the latest innovations. Continues Finocckì: “The end result was that we could run at speeds up to 750 m/min, meaning over 60 logs per minute, depending on the product. So we were able to raise our guaranteed output up to 46 logs per minute compared to about 35 logs on the older Sincro lines.”


When Metso and Perini got together to informally start studying the possibility of combining these two new innovations, they realized that the two new machines were very well matched. So with the LX line running at the average of 46 logs per minute, it can essentially handle all of the tonnage coming from the paper machine when everything is running smoothly. Of course this depends on the product being run.

“As we discussed the thinking behind each of our new concepts,” continues Myrén, “we realized that the speeds that we were considering for our paper machine matched very closely with the speeds that Perini was aiming for on its new converting line.

We were targeting a steady speed of about 1,200 m/min, whereas Perini was shooting for an average of around 600 m/min.

We therefore calculated that, once we combined the TAD tissue paper into two plies, the effective speed of both PM and converting was nearly equal.”

Therefore the two jumbo rolls, produced at 1,200 m/min, could be combined to run through the converting line at an average speed of 600 m/min. Of course, the converting line peak speed is higher since you need time for ramping up and slowing down at reel changes.


To move further, a study was proposed with the following target: Was it possible to develop an fficient solution to make approximately 30,000 tonnes/year of TAD, suitable for kitchen towel and toilet rolls, while still maintaining the capital cost per tonne equal to that of a large unit of 60-70,000 tonnes/year?

Eventually, after various adjustments, assumptions and streamlining, it was concluded that this target was indeed achievable by combining the following elements:

- Applying the new concept TAD machine

- Using the capacity and speed breakthroughs in converting and packaging

- Developing a Smart Link between the paper machine and the converting lines

- Running 24 hours a day, 7 days a week on both the paper machine and converting.

The resulting concept was termed TAD On-Line to denote the highly integrated nature of the process.

Basically the concept involves one tissue machine layed out in line with one converting line, which then is followed by a dedicated wrapper and bundler.

With the TAD 100 and Sincro LX technologies available, what was needed was a link between the two units. The solution that was developed, the Smart Link, offered many advantages which meant TAD On-Line could use the synergies of the two systems to integrate the production and converting of TAD in an extremely close manner (Figure on p. 70-71). Thus the production efficiency and cost effectiveness of the combined, integrated concept moved up to an entirely new level.

“The Smart Link tied the paper machine together very well with the converting and packaging line“, says Finocckì. “I can’t say that the Smart Link involved any breakthrough technology. It was simply a matter of applying existing methods in a smart layout to give a smooth flow of the parent reels to the converting line. We also had to engineer in a buffer which allowed us to some breathing room to cover the small downtime that is necessary on the converting line for things such as knife changes, film changes and so on.”


The buffer was eight spare spools on which about 2.4 hours worth of paper can be held. This meant that converting would have to be down for longer than 2.4 hours before the paper machine would need to shutdown. With a top speed of 750 m/min, the converting line has the capability to run up to 60 logs per minute if necessary to eat up tonnage that may have accumulated.

This simple buffer of eight reel spools replaces the extensive, and expensive, parent reel warehouse that is needed in most tissue operations. This alone saves substantial amounts of capital that would normally be necessary for construction of parent reel warehouses with specific fire protection systems and handling devices. Another advantage of TAD On-Line is less waste due to the fact that the parent reels are not handled at all with forklifts and resulting clamp damage.

Normally there can be over 500 parent reels in storage leading to a very heavy cost of working capital as well as long delays between the time when the paper is made and when it is converted on the rewinder.

The TAD On-Line is much more of a just-in-time operation leading to much faster feedback in case of defective parent reels.

Further discussion, analysis and calculations led to the conclusion that the smaller 2.7 m wide unit could compete very well with the standard 5.4-m machines. Based on a faster ramp-up curve, the total cost per ton of finished goods, including all capital costs, is lower for the 2.7 m line during the first two years. But as the 5.4 m line moves up the utilization curve, the advantage swings slightly to the bigger line.


These calculations are based on a number of assumptions, with the main ones being that the TAD On- Line concept is dedicated to production of premium quality kitchen towel (and toilet rolls) and that the total output of the TM has to be continuously absorbed by the converting line. Therefore tissue making and converting have to always be in production simultaneously.

Among the advantages that TAD On-Line concept appears to offer are the following:

- Simplified mill organization: One production unit, better teamwork, shared responsibility.

- Reduced personnel: Only 14/15 per shift for the whole operation

- Lower capital investment due to simplified machines

- Improved process quality, feedback and product flow

Although a fully utilized large line still provides the lowest production unit cost, the TAD On-Line concept can provide a very feasible alternative for small and medium production volumes. Of course this is all theoretical at this point but still the basis for considering such an integrated, low volume, high quality TAD line seems to be solid. And these innovations may be just in time, especially for the European market. •

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