Also referred to as Contrast of Jacket or Contrast Test.
The readability of a wire/cable is of critical importance for the proper installation, maintenance, and repair of the wiring system. That is the reason why UV laser marking of wires has become a widely used technology through the aerospace industry. It has several benefits over traditional ink marking of wires/cables. The contrast measurement test examination evaluates the contrast of the UV laser marked area with the unmarked parts of the wire.
To be classified as a laser markable wire/cable, the specimen must be marked with a laser marker with a specified laser fluence and then examined. The pass/fail criteria of this test are based on the specimen’s contrast measurement. The pass criteria are typically set above 50% contrast (a level that is readable in low light conditions) and the particular requirements are defined by the individual wire/cable specification. Specimens failing this test will have an average contrast measurement below the required contrast level.
Parameters that can be changed include:
- Preaging of the specimen
- Laser marking fluence
- Lighting conditions during contrast measurement