Laser chemical machining (LCM) utilizes the thermal induced chemical dissolution to remove material far below the melting temperature. Material removal during LCM with modulated laser power depends on the modulation frequency applied. The spatial frequency of the cavity corresponds to the spatial frequency of the laser power up to the threshold frequency. Above this threshold, the removal depth remains constant. The aim of this work is to investigate whether the modulation of the laser power can be used for surface structuring and what influence it has on the resulting surface structure. Therefore, line scans with different hatch spaces were generated to create a surface structure using a rectangular function of the output power with various frequencies. The frequencies used were selected below the threshold frequencies so that a sinusoidal structure in depth can be obtained along the machining direction. Besides the modulation frequency, the lines overlap and the phase angle between two neighboring lines was also studied. The experiments were conducted on titanium grade 1 with phosphoric acid. The investigation showed that by applying a modulated laser power with a frequency below the threshold and by placing the line with an overlap below 80% and a phase angle of 0 ° a sinusoidal structure is obtained in both xand y- direction. When the phase angle is set to 90 °, a braid like structure is obtained. This approach offers a promising tool for generating complex surface structures by modulating the laser power with a frequency below the threshold frequency.
Keywords
- 3D Structures
- Laser Chemical Machining
- Laser Processing
- Material Removal
- Surface Structuring