Process that utilizes specially-designed tooling usually vibrating at 15 – 80 kHz. Processes are designed to cause localized heating of thermoplastic materials that will cause some type of welded or fused joint to form. Benefits are the elimination of fillers and minimized heat stress on surrounding materials.
Light rays striking the white fibers of the mesh are reflected and scatter under the edges of the film. Light is also conducted through the fibers leading to yet more undercutting. Result: blurred edges, colour shifts. Sefar yellow dyed mesh prevents undercutting.