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As a reaction to the increasing market dynamics and complex requirements, today’s products need to be developed quickly and customized to the customer’s individual needs. In the past, CAD systems are mainly used to visualize the model that the product designer creates. Generative Design shifts the task of the CAD program by actively participating in the shaping process. This results in more design options and the complexity of the shapes and geometries increases significantly. This potential can be optimally exploited through the combination of Generative Design with Additive Manufacturing (AM). Artificial intelligence and the input of target parameters generate geometries, for example, by creating material for stressed areas, which in turn develops biomorphic shapes and thus significantly reduces the consumption of resources. This contribution aims at the evaluation of existing applications in CAD systems for generative design. Special attention is paid to the requirements in design education and easy access for students. For this purpose, three representative CAD systems are selected and analyzed with the help of a comprehensive example of mass reduction. The aim is to perform an individual result analysis in order to assess the application based on various criteria. By using different materials, the influence of the material for the generation is investigated by comparing the material distribution. By comparing the generated models, differences of the CAD systems can be identified and possible fields of application can be presented. By specifying the manufacturing parameters for the generation of the models, the feasibility of AM can be guaranteed without having to modify the results. The physical implementation of the example by means of Fused Deposition Modeling demonstrates this in an exemplary way and examines the interface of the Generative Design and AM. The results of this contribution will enable an evaluation of the different CAD systems for Generative Design according to technical, visual and economic aspects.
Additive manufacturing with plastics enables the production of lightweight and resilient components with a high degree of design freedom. In the low-cost sector, Material Extrusion as Fused Layer Modeling (FLM) has so far been the leading method, as it offers simple 3D printers and a variety of inexpensive 3D materials. However, printing times for 6FLM are very long and dimensional accuracy and surface finish are rather poor. Recently, new processes from the field of Vat Polymerization have appeared on the market, such as masked Stereolithography (mSLA), which offer a significant improvement in component quality and build speed at equally favorable machine costs.
This paper therefore analyzes the technical and economic capabilities of the two competing additive processes. For this purpose, the achievable dimensional and surface qualities are determined using a test specimen which represents various important geometry elements. In addition, the machine and material costs are determined and compared with each other. Finally, the resulting environmental impact is determined in the form of the CO2 footprint. In order to optimize the strength of the printed components, material properties of the tensile specimens produced additively with mSLA are determined. The use of ABS-like resins will also be investigated to determine optimal processing settings.
Plastics are used today in many areas of the automotive, aerospace and mechanical engineering industries due to their lightweight potential and ease of processing. Additive manufacturing is applied more and more frequently, as it offers a high degree of design freedom and eliminates the need for complex tools. However, the application of additively manufactured components made of plastics have so far been limited due to their comparatively low strength. For this reason, processes that offer additional reinforcement of the plastic matrix using fibers made of high-strength materials have been developed. However, these components represent a composite of different materials produced on the basis of fossil raw materials, which are difficult to recycle and generally not biodegradable.
Therefore, this paper will explore the potential for new composite materials whose matrix consists of a bio-based plastic. In this investigation, it is assumed that the matrix is reinforced with a fibrous material made of natural fiber to significantly increase the strength. This potential material should offer a lightweight yet strong structure and be biodegradable after use under controlled conditions. Therefore, the state of the art in the use of bio-based materials in 3D printing is first presented. In order to determine the economic boundary conditions, the growth potentials for bio-based materials are analyzed. Also, the recycling prospects for bio-based plastics will also be highlighted. The greenhouse gas emissions and land use to be expected when using bio-based materials are also estimated. Finally, the degradability of the composites is discussed.
Additive manufacturing enables the production of lightweight and resilient components with extensive design freedom. In the low-cost sector, material extrusion (e.g. Fused Deposition Modeling - FDM) has been the main method used to date. Thus, robust 3D printers and inexpensive 3D materials (polymer filaments) can be used. However, the printing times for FDM are very long and the quality of the dimensions and surfaces is limited. Recently, new processes from the field of Vat polymerization have entered the market. For example, masked stereolithography (mSLA) offers a significant improvement in component quality and build speed through the use of resins and large-area curing at still reasonable costs. Currently, there is only limited knowledge available on the optimal design of components using this young process. In this contribution, design guidelines are developed to determine the possibilities and limitations of mSLA from a design point of view. For this purpose, a number of test geometries are designed and investigated to obtain systematic insights into important design features, such as wall thickness, grooves and holes. In addition, typical problems in additive manufacturing, such as the design of overhangs and fits or the hollowing of components, are investigated. The evaluation of practical 3D printing tests thus provides important parameters that can be transferred to design guidelines of components for additive manufacturing using mSLA.
Fused Filament Fabrication (FFF) is a widespread additive manufacturing technology, mostly in the field of printable polymers. The use of filaments filled with metal particles for the manufacture of metallic parts by FFF presents specific challenges regarding debinding and sintering. For aluminium and its alloys, the sintering temperature range overlaps with the temperature range of thermal decomposition of many commonly used “backbone” polymers, which provide stability to the green parts. Moreover, the high oxygen affinity of aluminium necessitates the use of special sintering regimes and alloying strategies. Therefore, it is challenging to achieve both low porosity and low levels of oxygen and carbon impurities at the same time. Feedstocks compatible with the special requirements of aluminium alloys were developed. We present results on the investigation of debinding/sintering regimes by Fourier Transform Infrared spectroscopy (FTIR) based In-Situ Process Gas Analysis and discuss optimized thermal treatment strategies for Al-based FFF.