The wetting of lubricants based on a fatty alcohol and of water-based lubricants of the tool surface during the milling process is essential for obtaining workpieces of high quality. The wettability of the milling tool can be influenced by applying microstructures. Ultrashort pulsed laser radiation is a useful tool to produce surface structures in the micro- and nanometer range which modify the wettability of a surface. 

In the presented work, microstructures were generated on cemented tungsten carbide surfaces using ultrashort laser pulses. The type of microstructures was varied by varying the spatial overlap of the laser pulses by using different feed rates while keeping the maximum average power of 10,76 W and the constant repetition rate of 500 kHz. By increasing the pulse overlap larger surface structures with increasing roughness could be created. To consider aging the contact angle was measured 30 days after structuring. For deionized water, decreasing contact angles were measured on surfaces of increasing roughness (insets). On the roughest structure, a contact angle of θ = 0° was measured for deionized water. The same rough surface also resulted in a low contact angle of θ = 8° for a lubricant based on a fatty alcohol. Therefore, for this structure superhydrophilic behavior as well as high wettability of a lubricant based on a fatty alcohol could be demonstrated.

In the talk, the latest results regarding the wettability of laser-structured surfaces with different lubricants will be presented and discussed.