Design surfaces by laser remelting

Molds and dies are used today in the manufacturing of a wide range of industrial products. They have a broad field of applications from the air and space technology, the automotive sector, to electrical engineering, to household products and consumer goods. The surface of a part or product strongly influences its properties and functions e.g. it's visual appearance. The gloss thereby reflects one of the most important properties of a surface when it comes to evaluate the visual appearance. Therefore, among others, in this paper the influence of laser polishing on the generated specular gloss is investigated for the hot work steel 1.2343 (AISI: H11). On the one hand laser polished surfaces are measured by WLI and investigated by a spectral analysis of surfaces roughness. A spectral analysis is achieved by a discrete convolution of the surface profile with a Gaussian loaded function similar to ISO 11562. On the other hand specular gloss measurements were carried out at 20°, 60° and 85°. For the experiments a fiber‐coupled solid state disc laser (Yb : YAG; Q‐switched) is used (PL,max = 550 W; repetition frequency: fP = 5–20 kHz, pulse duration: tP = 0,7–3,5 µs, pulsed and cw‐operation). In general, scanning velocity and average laser power are two crucial procedural parameters for laser polishing with significant influence on the resulting surface roughness. These procedural parameters are investigated systematically, while other procedural parameters, such as laser beam diameter dL = 250 µm and track offset dy = 25 µm were kept constant. By this a significant reduction of roughness was achieved, especially for the wavelength interval λ