Pulsed laser stripping of polyurethane-coated wires: A comparison of KrF and CO₂ lasers

Compared to mechanical, thermal, electric, or chemical means of removing plastic wire insulation, laser removal offers precision and speed without the necessity of contacting the material. Utilizing the technique of excimer laser ablation of organic polymers, it is shown that excimer laser removal of polyurethane-type wire insulation proceeds with much higher precision and cleanliness than does pulsed CO2 laser wirestripping. A reason for this difference is polyurethane's much higher absorptivity of ultraviolet compared to infrared radiation. Scanning electron microscope photographs of both stripped wires and ablated regions on polyurethane-coated flat disks clearly show the superior quality of the excimer method. The paper concludes with a discussion of the photophysical parameters and mechanisms responsible for the large difference between excimer and CO2 stripping.