Depending on the material and application of the product, plastic cables or tubes can be marked with a UV or a fiber laser. UV is for plastics like silicone, that must not be impacted by too much laser heat due to its surface structure. Fiber is an appropriate laser method for plastics like Nylon which is often disposed to environmental strain.
The marking process applied here is called color change or frothing: The carbon in the plastic oxidizes to form CO2, which comes out of the plastic and forms a layer of froth. The tone of the created color depends on the material composition. Tubes or cables get marked “on the fly” while being processed in high speed production lines with an integrated laser marking unit.