The effect of diode laser wavelength on the clearweld™ welding process

Abstract

The acceptance of laser transmission welding of plastics by industry has recently increased due to the development of reliable, efficient direct diode lasers. A development of this process, Clearweld™, where an infra-red absorbing ink is used to generate heat and subsequent bonding is also now moving into industrial application. A key aspect of this process is the degree to which different diode laser wavelengths are absorbed by the ink and this work addresses this issue. It is often impossible to directly compare the effect of different laser wavelengths in materials processing applications simply because changing the source wavelength inevitably changes many other variables such as spot size, average power and hence power density and other laser parameters. In the case of direct diode lasers, it is a straightforward task, if identical fiber coupled packages are available that differ to all practical purposes only in the wavelength of the diode laser bar. A direct comparison is therefore achieved between different wavelengths for a particular weld joint configuration.The acceptance of laser transmission welding of plastics by industry has recently increased due to the development of reliable, efficient direct diode lasers. A development of this process, Clearweld™, where an infra-red absorbing ink is used to generate heat and subsequent bonding is also now moving into industrial application. A key aspect of this process is the degree to which different diode laser wavelengths are absorbed by the ink and this work addresses this issue. It is often impossible to directly compare the effect of different laser wavelengths in materials processing applications simply because changing the source wavelength inevitably changes many other variables such as spot size, average power and hence power density and other laser parameters. In the case of direct diode lasers, it is a straightforward task, if identical fiber coupled packages are available that differ to all practical purposes only in the wavelength of the diode laser bar. A direct comparison is therefore achieved between...