Andritz Asselin-Thibeau has developed a new process that allows webs with heavier basis weights and/or thicknesses to be fed to the crosslapper, using the design speed capabilities of the crosslapper. With this technology, known as ACS, heavier and thicker webs can be fed into the top carriage without air bubbles forming. Air bubbles traditionally have an adverse effect on feeding of such webs into the crosslapper. When the card web is compressed between two aprons, the air compression generates a reverse air flow, which then forms the bubbles. The formation of bubbles translates into loss of control of the web by generating creases and a drop in evenness, thus affecting the uniformity of the batt generated in crosslapping.
The ability to generate uniform cross-width weight profiles in the finished needlepunched felt is, however, not the final hurdle in optimizing uniformity in the manufacture of a finished nonwoven. Weight uniformity does not always translate into performance uniformity in the nonwoven fabric.
With ACS technology, it is possible to feed card web structures to the crosslapper that the current equipment previously could not handle. The advantage of this is manifold; higher rates of production can be achieved, either through higher ingoing speeds and/or by feeding in heavier web weights at the same speed.
A further advantage of ACS is the value it adds to the end products (for automotive felts, for example, as shown below). These products have to be molded into different shapes, with different stretch percentages and in multiple directions with sharp angles. The ability to feed carded condensed webs into the crosslapper means that the fiber orientation of the web can be more balanced between MD and CD, and the web retains a high elongation potential without tearing apart. Thus, webs with a better MD/CD balance and also Z-direction orientation can be used to form batts with a unique balance of physical uniformity across the working width.
For automotive applications, the key is to obtain nonwoven fabrics with balanced strength values for up to 50% elongation (see sketch below). Physical uniformity (both tensile and elongation) across the working width translates into felts which perform similarly at any position across the width of the finished fabric.
The technological leap with ACS, enabling production of batts with uniform weight and performance, provides a competitive advantage to factories using this advancement. Uniformity in both criteria provides better performance for end users and also enables the nonwoven manufacturer to lower basis weights because performance is more uniform regardless of where the fabric is taken across the width of the finished nonwoven fabric. It was this ability to save manufacturing costs 20 years ago that launched the Profile generation, and today, ANDRITZ Asselin-Thibeau has taken a similar leap on the market for nonwovens manufacturing capability.