What is the processing principle of needled non-woven fabric?

What is the processing principle of needled non-woven fabric? The basic principle is: using the triangular section (or other section) edge with barb to puncture the fiber mesh repeatedly. When the barb passes through the web, the fibers on the web surface and local inner layer are forced into the web. Due to the friction between the fibers, the original fluffy web is compressed. When the needle exits the web, the inserted fiber bundle breaks away from the barb and remains in the web. In this way, many fiber bundles entangle the web so that it can no longer return to its original fluffy state. After many times of needling, quite a lot of fiber bundles are punctured into the web, which makes the fibers in the web entangle with each other, thus forming needled nonwovens with certain strength and thickness.