One reason for using mat in composite layups is to:

The use of mat in composite layups primarily serves to increase the adherence of layers. Mat, often made from fiberglass fibers, is laid down in a random orientation and bonded with resin. This structure maximizes the surface area available for adhesion between subsequent layers, ensuring a strong bond throughout the composite. This increased interlayer adhesion is critical to the performance and durability of the final composite material, as it helps to prevent delamination and enhances the composite’s overall mechanical properties.

The other considerations in composite manufacturing, such as weight, production time, and aesthetic appearance, are important, but they do not directly relate to the fundamental purpose of using mat in the layup process. While the mat can contribute to a more appealing appearance, its primary role revolves around improving structural integrity and the bonding of the layers.