A Wet-End in Full Harmony – and Under Full Control


Jan 11, 2023

Original Article was reprinted from the International Paperboard Magazine

Corrugated board producers have different requirements depending on the markets they operate in. When the markets are different, why should the wet-end equipment be the same? It should not – there is no one-size-fits-all corrugator or wet-end equipment. BW Papersystems offers modular corrugating solutions that are customized to the need of the board producer. With the Harmony corrugator wet-end, the company offers equipment that brings productivity, reliability, and competitive pricing in harmony. 

With the worldwide growth in e-commerce the demand for corrugated material in general is high. Depending on the regional market, demand can manifest itself in different ways. In North America and Western Europe, the growing e-commerce market generates demand for enhanced strength properties, high-quality printing, better print finishes and high-quality material to enhance brand identity on e-commerce packages and to improve applications with direct food contact. 

Translating these market needs into equipment requirements, results in a reliable, high output corrugator with advanced automation and controls that produces high-quality corrugated board. In the highly competitive European market, a competitive price-performance ratio is key. This is where the Harmony corrugator and its well-balanced features come into play. It is available in widths from 2500mm to 2850mm and speed ranges from 300 to 350 m/min., resulting in an average production capacity of approx. 12 million m2/month of quality board. 

Harmony wet-end ensures efficient and reliable production of high-quality board
The wet-end of the corrugator is where the foundation is laid for board quality in terms of flute integrity, flatness, and surface printability. The Harmony wet-end combines proven components from BW Papersystems, drawing on decades of experience and expert corrugating process know-how. Let’s have a closer look at the individual wet-end components in a Harmony line.

Keep it rolling with Splicers and Rollstands 
Modern corrugators are run with minimal operators, that is why BW Papersystems designs rollstands and splicers to include the highest level of automation to make the operation easy and reliable. Splice preparation with the ‘Auto Index’ feature is simple and quick. The prepared splice is automatically positioned for the optimum splice seal. To prevent a tear out on unmarked paper mill splices, a Mill Splice Detect option is available. Splicers from BW Papersystems allow reliable splicing at high speeds and even with light paper grammages of 60 to 90 gsm. Rollstands can be equipped with dual size chucks for improved flexibility in the sourcing of paper. Automatic core ejection saves time for operators and reduces injury risk. The rollstand and splicer combination ensures the paper rolls keep rolling, web tension is accurate, and waste is kept to a minimum by avoiding paper breaks and ensuring simple splice preparation. 
Singlefacer – the heart of the corrugator
Without the singlefacer there is no corrugated board. BW Papersystems’ singlefacers are robust and easy to operate. The positive pressure machines are available as pressure-roll or pressure-belt type with quick flute change capability. The Singlefacer provides a high level of automation, such as automatic cassette flute type detection, automatic glue dam positioning, automatic wrap arm control, metering roll and glue application gaps. An easy cleaning and maintenance access ensures higher uptime as it avoids dirt and debris build up. The singlefacer flute cartridge can be changed from the operator or drive side to suit an existing layout. Automation functionalities of the singlefacer are linked to the corrugator supervisory control system – the intelligent Orchestro Control System from BW Papersystems. 

It’s getting warm – and flat - with Preheaters and Preconditioning 
BW Papersystems preheaters and preconditioners are available in all sizes. The drums are driven at variable speed, ensuring a consistent web tension without causing tear outs or creating end-to-end warp. Accurate wrap arm position ensures a uniform heat transfer, with even web tension for production of flatter board. The preheaters are designed to work with modern corrugator process control systems, like Orchestro. that will control the Wrap arms are automatically controlled to a desired paper temperature based on the order recipe or on feedback from an optional warp measuring device. With its ‘Infusion’ steam injection paper conditioning system, BW Papersystems offers a remarkable method to properly precondition the paper. With the Infusion system fitted to a drum, a flat hotplate, or a curved hotplate, the singleface or outside liner is impregnated with superheated steam that quickly boosts the paper temperature without over drying, making the paper pliable and ready for flute forming or to accept glue application. Glue cures faster and speeds are boosted better than with other heating plate, drum, or steam shower methods. The Infusion hotplates can be added to any corrugator singlefacer, glue machine or doublefacer.

The Glue Machine – just enough, never too much
In the Harmony wet-end, the glue machine applies the correct amount of starch to the singleface web, whether micro-flute or large flute types. Due to this product defects, such as wash-boarding, warp, and poor web edge bonding are avoided. The glue roll type is selected to meet a customer’s production requirements. A rider roll or contact shoe system is available to keep the singleface web against the glue roll with the correct amount of contact, to avoid crush and to pick up just enough glue for the bond to occur. The glue gap settings automatically adjust according to corrugator speed and product requirements. Glue machines can be installed as an individual machine or part of a wet-end line solution. When the glue machine is part of a full corrugator, the Orchestro supervisory system controls glue gaps and glue dam settings. 

The crushless Doublefacer – for improved board quality
The Cool-Vac doublefacer from BW Papersystems produces flat, well-bonded, dry and crushless corrugated sheets of the highest quality - ready for immediate printing, folding, gluing, and die cutting without additional curing time. The doublefacer is one of the key machines in the corrugating process. The Cool-Vac doublefacer eliminates crush and web weave and thereby improves board quality. The secret of the Cool-Vac: it combines a high energy heating section with a Vacuum Traction Section (VTS). This vacuum pulling section reduces web crush, whilst removing excess moisture from the web prior to it entering the dry-end section of the corrugator. In contrast to this advanced technology, conventional doublefacers squeeze the board to pull it forward, resulting in noticeable board crush and compromising the strength of the finished box. The Cool-Vac doublefacer is equipped with gun drilled (peripheral heated) hotplates, with a rapid condensation removal design, and the unique Infusion steam technology, for retaining box strength especially on lighter paper weights. Cool-Vac doublefacer – it’s not a crush, but true love with perfect corrugated sheets.

Orchestro: full control over the Harmony wet-end 
The Harmony wet-end offers a balanced combination of productivity, reliability, and price-performance ratio – the Orchestro system has everything under control. For the doublefacer, Orchestro automatically controls steam and shoe pressure for each zone, based on the current production. Orchestro will automatically adjust its parameters for the next order with no operator intervention. For the singlefacer, it is automating the control of paper temperature, glue application, roll pressure and bridge storage control. The result - all shifts use the same operating procedures and settings, leading to a consistent production and maximized output. In addition, the system includes high automation features such as speed synchronisation, automatic order change and closed loop process control for the whole corrugator. Orchestro uses technology to make production simple. 

The Harmony wet-end from BW Papersystems is designed for medium to high volume production operations. Automation features and the intelligent Orchestro control system make it a good match for European corrugated plants. As with all BW Papersystems corrugators and components, customers can rely on decades of experience and expert know-how from its long heritage in the corrugating industry. 

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We’re thrilled to have partnered with BW Papersystems on this project. BWP’s first-rate products, and the fact the machine was built right here in Wisconsin, made them the obvious choice for this capital investment.
Scott Monnot, VP & General Manager, Sheboygan Paper Box Company, Sheboygan, WI, USA