System for locating a woven preform tracer

A method for controlling a woven preform of a composite material part by a system, the preform comprising on its surface at least one strand comprising fibers of a first material forming a tracer and strands of fibers of a second material, the first material being chosen from glass, aramid and alumina oxide, the second material being chosen from carbon and silicon carbide,

• wherein the system includes:
• a camera,
• a light source emitting an unpolarized incident beam adapted to be directed towards the preform,
• a polarizer having a first polarization direction, the polarizer being adapted to polarize the unpolarized incident beam before interacting with the preform to obtain a polarized incident beam, and
• a cross analyzer having a second polarization direction,
• wherein the camera is adapted to film a reflected beam resulting from the interaction of the polarized incident beam with the preform, the reflected beam having previously passed through the cross analyzer, so as to locate the tracer of the preform,
• the method comprising a step of:
• a) controlling that the tracer of the preform is within a predefined interval from the images filmed by the camera.

A set comprising:

• a woven preform of a composite material part, wherein the preform comprises on its surface at least one strand comprising fibers of a first material forming a tracer and strands of fibers of a second material, wherein the first material is selected from the group consisting of glass, aramid and alumina oxide, and wherein the second material is selected from the group consisting of carbon and silicon carbide;
• and
• a system for locating a tracer of the woven preform, wherein the system comprises:
• a camera,
• a light source emitting an unpolarized incident beam which is directed towards the preform;
• a polarizer having a first polarization direction, the polarizer polarizing the unpolarized incident beam before interacting with the preform to obtain a polarized incident beam;
• a cross analyzer having a second polarization direction,
• wherein the camera of the system films a reflected beam resulting from the interaction of the polarized incident beam with the preform, the reflected beam having previously passed through the cross analyzer, so as to locate the tracer of the preform.