Inspecting:   In the RINGTREAD production philosophy, operator expertise is irreplaceable and, along with specific operating machines, makes it possible to determine whether or not a casing can be retreaded. The ITT inspection machines use the vacuum shearography technique to reproduce the image of the deformations at a microscopic level. By modifying the tire's load conditions and overlapping images, the machine can detect defects that indicate separations. This technique is much more precise, faster and more reliable than the methods used by other retreaders today: this makes it possible to create a retread with the best performance, reliability and service life.