When processing magnet wire with a CO2 laser, a thin layer of insulation remains on the conductor. This residual adherent enamel layer is non-conducting and sufficient to prevent bonding if soldering, tinning or welding. Consequently a different approach is required for laser stripping to ensure the complete removal of the insulation. This led to a novel method to removing bonded films and coatings. The essence of this is to select a laser wavelength at which the coating or film is largely transparent, but which is absorbed by the substrate, i.e. the antithesis of the normal approach. The novel approach of the Sienna 900 and 800 Duo is to take a wavelength that is ineffectively absorbed by the material that we are in fact aiming to remove. In addition by using a pulsed laser with high peak power pulses it is possible to generate the release of intense bursts of energy at the interface between the coating and the substrate. The effect of using this approach is to delaminate the coating and to eject it at high speed from the wire surface. A key added advantage is that the laser also removes any oxide layer from the conductor surface, thereby leaving it in the perfect state for bonding.
Productronica innovation award 2015: hall B2, booth 245