Wiring Harness News May-Jun 2022 - Page 42

42 MAY / JUNE 2022 Wiring Harness News INDUSTRIAL INFO-TAINMENT

UV Laser Marking of Wire Insulation Materials

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The question of what exactly happens to TiO2 particles under intensive UV light exposure is outside of the scope of this article , but the resulting change of color is irreversible . For example , long-term stability of UV laser marking on TiO2 doped ETFE films was investigated in Mc- Donnell Douglas Research Laboratories in 1990 . The marking showed little change during either thermal aging ( 770 hours at 229oC ) or simulated solar irradiation ( equivalent to 17 years of UV exposure in the Arizona desert ).
The marking contrast is proportional to TiO2 concentration ; however , excessive amounts may damage the insulation . Normally 2-4 % by weight is enough to achieve a good contrast . Table 1 specifies typical contrast levels achievable by directUV laser printing on the wire con-
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Figure 4 . Schematic representation of UV laser beam path through a transparent media dopped with Ti0 2 particles .