# Development Workflow for Manifolds and Fluid Components Based on Laser Powder Bed Fusion
## 1 Introduction  
Additive manufacturing (AM) describes all manufacturing processes in which the part is fabricated by adding volume elements layer by layer to produce the desired geometry. The added elements are directly derived from the 3D data [1]. AM technologies have been advancing steadily through the years. Especially the sector of metal AM matured from niche applications to mainstream manufacturing and is being accepted as a valuable production process for demanding engineering tasks. For metal applications, laser powder bed fusion (LPBF) is the most widespread manufacturing principle [2]. When designing parts specifically for AM, these technologies yield unique characteristics in advanced geometric freedom, part consolidation, and product customization in comparison to other manufacturing processes. Through the given geometric freedom, new potentials in the performance and economic efficiency of the product are enabled, which can be realized through advanced design. If such a design can consolidate multiple parts of an assembly, additional improvements in size, weight, and assembly effort are achievable [3]. In the LPBF manufacturing process, differences in the individual geometry of parts manufactured in one build job have minor influence on the economics of the build job compared to conventional manufacturing methods. This leads to an economic feasibility of a lot sizeof one and makes the technology therefore practical for highly customized products [4]. However, these potentials are not easy to identify nor to realize. It requires the designer to have a fundamental understanding of the technology and to re-think the system-level design of the product [5]. Existing, universal product development methodologies are applicable for AM parts, but can hardly exploit the given potentials efficiently due to the design complexity and multitude of possible solutions [6]. Nonetheless, as a development of a completely new design process is neither efficient nor possible, development guidelines for AM products should be based on established methodologies and further recognize the specific potentials and limitations of the technology. As the VDI 2221 [7; 8] guideline is widely accepted as a core standard for the development of technical products and was previously suggested for an AM specific methodology [9]. [PERSON] bases the general structure of his comprehensive method for the development of AM parts onto it [5]. As for any other manufacturing method, design guidelines have to be followed for a qualitative and economic fabrication of the designed part. The established methods of design for manufacturing (DfM) aim for design solutions with minimum manufacturing costs for a given manufacturing technology. Even though such guidelines for favorable manufacturing are still an elementary part of a design for additive manufacturing (DfAM), these methods shall further support the exploration of AM-enabled potentials and possibilities. [PERSON] et al. propose to differentiate opportunistic DfAM, restrictive DfAM, and dual DfAM [10]. Opportunistic DfAM methods shall enable the designer to explore innovative solutions enabled by the possible geometric complexity of AM products. The solution space of such methods is not narrowed by the limitations of the AM technology as in the definition of conventional DfM. These limitations are covered in the class of restrictive DfAM methods. In these, design rules are defined, that guide the designer to create a part with sufficient manufacturing quality. The majority of such design rules are developed in university research through test series [11; 12; 13; 14]. These restrictions can be quantified as for minimum radii or wall thicknesses, as well as general guidelines for a sufficient manufacturing result [14]. They are more and more transferred into official design guidelines [15] and textbooks [4]. Finally, methods utilizing a combination of both, restrictive and opportunistic DfAM, are considered to be the most efficient for a holistic product design manufactured by AM technologies.