appareil laser

Laser ablation achieve when a very localized area of a material. Which target by the focused beam of an industrial laser, undergoes either fusion or sublimation. The fused material expel, resulting in a change of the topography of the targeted material. The depth of material affected can amount to a few tenths of millimeters.

The Laser Ablation Process

All materials have ablation thresholds. It is a property that is unique to a material. When intensity (energy per surface area) is above the ablation threshold, the laser ablation occurs. But if the intensity is below the ablation threshold, nothing happens, apart from a slight temperature increase.

Laser ablation is the mechanism through which most laser material processing occurs. Other material processing techniques also exist. The most noteworthy are laser carbonization for plastics as well as laser annealing, laser etching and laser engraving for metals.

In the following section, you will find a list of factors that use to optimize laser ablation and a few industrial applications of laser ablation.

Factors to Consider for a Successful Laser Ablation Process

• Wavelength: When light hits a surface it either reflect, absorb, transmit or a combination of the three. Also, the reflectivity of a material varies as a function of the laser’s wavelength. Therefore, a laser that emits at a wavelength that has a low reflectivity should always favor. For most metals, Laserax’s fiber lasers are a good choice.
• Diameter of the beam: Changing the diameter of the beam impacts the intensity of the laser that hits the targeted material. All else remaining equal, increasing the beam diameter will reduce the intensity.
• Number of passes: With certain jobs that require deep engravings, you might get better results with several passes rather than increased intensity with one pass.
• Focal distance: As the focal distance fix for a given lens, some manual adjustments might be necessary. For optimal results, it is important that the targeted area of the parts being processed be at, or very close to, the focal distance.

• Line feed

  The speed at which the laser beam sweeps the surface to process has an impact on the intensity delivered to the surface, especially when you’re using a pulsed laser. The speed of the line feed will determine the spacing between each laser pulse on the targeted materials.

• Distance between successive lines: Changing the distance between the lines has a similar effect as that of the line feed. The shorter the distance, the tighter successive lines will be; more energy will transfer to the material per unit surface.
• Power of the laser: The more powerful a laser is, the more intensity it can deliver over a given period of time.
• Pulse frequency: It is possible to change the elapsed time between each pulse. Reducing the pulse frequency will reduce the energy delivered to the targeted material per unit of time (if we keep the energy of the pulseconstant).

  Increasing the pulse frequency is a little bit trickier. When the elapsed time between each pulse reduce, the intensity increase up to a certain point, corresponding to the maximum optical power (P._MAX) level of the laser.