Direct Laser Fabrication of Compositionally Complex Materials

Additive manufacturing (AM) opens up the possibility of a direct build-up of components with sophisticated internal features or overhangs that are difficult to manufacture by a single conventional method. As a cost-efficient, tool-free, and digital approach to manufacturing components with complex geometries, AM of metals offers many critical benefits to various sectors such as aerospace, medical, automotive, and energy compared to conventional manufacturing processes. Direct laser fabrication (DLF) uses pre-alloyed powder mix or in-situ alloying of the elemental powders for metal additive manufacturing with excellent chemical homogeneity. It, therefore, shows great promise to enable the production of complex engineering components. This technique allows the highest build rates of the AM techniques with no restrictions on deposit size/shape and the fabrication of graded and hybrid materials by simultaneously feeding different filler materials. The advantages and disadvantages of DLF on the fabrication of compositionally complex metallic alloys are discussed in the chapter.

Functional Metallic Microcomponents via Liquid-Phase Multiphoton Direct Laser Writing: A Review

We present an overview of functional metallic microstructures fabricated via direct laser writing out of the liquid phase. Metallic microstructures often are key components in diverse applications such as, e.g., microelectromechanical systems (MEMS). Since the metallic component’s functionality mostly depends on other components, a technology that enables on-chip fabrication of these metal structures is highly desirable. Direct laser writing via multiphoton absorption is such a fabrication method. In the past, it has mostly been used to fabricate multidimensional polymeric structures. However, during the last few years different groups have put effort into the development of novel photosensitive materials that enable fabrication of metallic—especially gold and silver—microstructures. The results of these efforts are summarized in this review and show that direct laser fabrication of metallic microstructures has reached the level of applicability.

Direct Laser Fabrication of Cylindrical Lenses in Wide Band Gap Materials

The Fluorine laser microstructuring technique enables the direct laser fabrication of cylindrical lenses and lens arrays thereof in wide band gap materials. For the mask projection technique, a special mask geometry was calculated, which allows the fabrication of cylindrical lenses with a nearly optimum curved surface. Based on our results of processing fused silica and borosilicate glass, we investigated the possibility to apply these microstructuring technique to wide band gap materials like calcium fluoride. The radius of curvature (ROC) can be adjusted by the process parameters laser pulse fluence and pulse-to-pulse overlap in a range of 130 to 450 µm micrometer. A minimal surface roughness of 100 nm RMS can be reached.