Xella’s factory in Vuren, the Netherlands, has started this year in full swing with an upgraded cutting line (Fig. 1). With an extremely short factory downtime, resulting from very careful planning and preparations, this project was executed smoothly as a joint effort from the teams of Xella Netherlands (“Xella”) and Aircrete Europe (“Aircrete”), who was engaged as the technology partner for this project.
Fig. 1: Upgrade of the first section of Xella Vuren’s cutting line with the replacement: Aircrete Cross Cutter
With an increasing demand for AAC products, particularly for the Super Smooth partition panels, the process reliability has never been more important. It was a major consideration for the decision to upgrade the first section of the cutting line with the new generation Aircrete Cross Cutter. In addition to increased reliability, the new equipment also ensures a higher product quality and reduced energy consumption, thereby hitting the ground running for Xella in 2022.
Background project
As part of a continuous drive to improve process and product quality, Xella decided in 2021 to upgrade the first section of its cutting line. This upgrade leads to the quality of the cut product increase, reduction of wire breakage (resulting in production interruptions, capacity loss and waste increase) and energy consumption reduction as well. The cross cutter of the cutting line is not a standalone part of equipment, but an integral part of the overall cutting line. It makes an upgrade more challenging from an engineering point of view to ensure the upgrade would continue to interact smoothly with the existing electrical control and safety circuits. Also, from an installation point of view, these types of projects are more challenging. As the cutting line is a fundamental part of the factory and production process, the required downtime for installation would have to be minimized as much as possible to avoid excessive production loss.
Technical description and advantages
The latest design of the Aircrete Cross Cutter ensures higher cut precision whereby TLMB (Thin Layer Mortar category B) standards can be easily met. The cross cutter is characterized by an inclined frame with oscillating wires (Fig. 2). By creating an inclined cross cut, the wires leave the cake at an angle, thereby minimizing the sling effect and damage to the cake caused by it (resulting in an optimal top crust removal process).
Fig. 2: Frame of the Aircrete Cross Cutter comes with the option of a variable and programmable lifting speed
Another beneficial side-effect is that the thickness of the top crust can also be reduced, allowing for less raw materials required for the casting and less return slurry during the production process and therefore, also less energy consumption is required. Furthermore, with the option of a variable and programmable lifting speed of the frame, the speed of the wires at the end of the cross cut cycle (i.e. when the wires leave the cake) can be reduced. This minimizes the top crust damage without having to compromise cycle times. Finally, with the use of A-quality brands and components, the quality, reliability and lifetime of the equipment is ensured as well.
The Aircrete Cross Cutter allows for large flexibility when it comes to product dimensions in Xella’s product portfolio. The wires of the cross cutter can be positioned on any position from 0 to 6 meters, with increments as short as 5mm. All cross cut wires oscillate back and forth and the wire tensioners are designed in a way that no more than 2 consecutive wires move in the same direction, neutralizing lateral forces and avoiding the cake to ‘rock’. The wire oscillation ‘stroke’ is adjustable, and the wires oscillate within the rigid cross cut frame, where two reciprocating moving cutting shafts support alternate wires. The wires are hold by air-tensioned holders on precision grooved segments, to ensure optimal accuracy on the cross cut (i.e. height of the block or the length of the panel) (Fig. 3).
Fig. 3: Advantages of the new generation Aircrete Cross Cutter
Project preparation and implementation
Being the global expert of flat-cake cutting technology and having a solid track-record of designing complex modernization projects which need to be implemented with minimized downtime, Aircrete Europe was engaged as the technology partner for this important project, of which the engineering started in the summer of 2021. During the engineering and manufacturing of the cross cutter, Xella and Aircrete teams have worked intensively together to prepare thoroughly for the installation and commissioning phase. Clear scope divisions and responsibilities were defined, and a detailed installation preparation plan was worked out by both teams. The installation was realized in the winter of 2021/2022 (Fig. 4) and due the thorough planning a cooperation between the teams, the actual dismantling of the old equipment and installation of the new Aircrete Cross Cutter was realized ahead of the schedule, reducing the scheduled downtime of 14 days with multiple days.
Fig. 4: The installation of the Aircrete Cross Cutter is completed ahead of schedule
About Xella
Xella Netherlands is a part of the Xella Group, one of the world’s largest producers of autoclaved aerated concrete and the only producer of AAC products in the Netherlands with 3 factories. Xella distinguishes itself in the building world as a specialist of supplying high-quality building materials for both the residential and non-residential construction. Within its AAC segment, Xella produces AAC panels and blocks under the Hebel, Ytong and Multipor brands.
Are you looking for a cutting line upgrade in your AAC plant? Contact us now!