The development of 4D-printing technology enables the fabrication of smart structures capable of transforming in response to external stimuli, offering potential for future minimally invasive biomedical applications. This study explores a direct 4D-printing approach for producing thermally actuated polylactic acid (PLA) components, focusing on self-expanding vascular stent prototypes. Unlike conventional 4D printing, which typically requires a separate post-printing programming step (e.g., heating, mechanical loading, cooling, and unloading), direct 4D printing embeds the programming phase directly into the layer-wise printing process by controlling the adjustment of process parameters, so that components are ready for shape transformation immediately after fabrication. A systematic experimental workflow was applied by combining a problem-solving methodology with action research and structured experimentation to identify and optimize the key parameters governing shape-shifting behavior. Bilayer plate structures were fabricated via fused filament fabrication (FFF) using multiple PLA material combinations and were thermally actuated under controlled conditions to characterize the influence of printing speed, printing temperature, and infill pattern on the magnitude and directionality of deformation. Building on these results, three functional demonstrators were developed, culminating in a grid-based cylindrical prototype that achieved approximately 5.8% radial expansion upon actuation at temperatures above 80 °C. Overall, the results suggest the fundamental technological feasibility of direct 4D printing as a manufacturing route for thermally actuated components, serving as a foundational proof-of-concept for future patient-specific, self-deploying medical devices.

4D printing is a new technology that uses 3D printing to produce objects made of smart materials which can change over time in response to external stimuli, effectively adding time as the fourth dimension. Currently, ambitious research groups are primarily investigating 4D printing. However, this new technology has only been integrated into the engineering curriculum through specialized courses in a few cases so far. This contribution therefore describes an innovative approach to integrating 4D printing into engineering education. At its core is a workshop for Master's students in Mechanical Engineering which aimed to develop an intelligent robot using bionic muscles. The students formed small teams and worked on this challenging task together. They created the design using magnet-responsive material processed with 4D printing and controlled by external magnetic fields, and used a product development method to structure the process, systematically recording and evaluating requirements and possible solutions. The students also used an innovative online platform to facilitate collaboration and promote the exchange of ideas. A pellet 3D printer was used to print the smart materials. The results showed that both teams were able to produce functioning bionic muscles. A before-and-after survey confirmed a significant improvement in the students' skills, particularly in 4D printing, soft robot design and smart material design. Evaluating the workshop elements showed that using smart materials and CAD design, developing different design variants, and applying additive manufacturing all contributed significantly to learning success.

Processes and materials in Additive manufacturing have advanced significantly in recent years and are increasingly being used in both scientific and industrial applications. Therefore, it is important to integrate these new additive processes and the selection of suitable materials into engineering studies. This paper presents an innovative course called “Workshop Additive Manufacturing”, which provides knowledge about additive manufacturing through a project. In this project, students work in multidisciplinary teams to develop a product and realize it through additive manufacturing. The development of a scale model wind turbine as a functional and economic prototype for sustainable energy generation is a key feature of this new course. The students carry out all the steps from idea generation to the manufacturing of the models. This includes the development of a gearbox and the integration of a generator. At the end of the project, the models are tested for functionality and performance in a simple wind tunnel. In order to examine the changes in the students’ knowledge and skills during the course, they will be surveyed in eight different areas before and after the workshop. Furthermore, an evaluation was conducted in order to ascertain the students’ workload during the various phases of product development, as well as the influence of the different components of the course on learning success. The results demonstrated that the students were able to significantly improve their skills, particularly in the areas of wind turbine development, application of design methods for sustainable design and practical knowledge of additive manufacturing.

Additive manufacturing has increasingly found its way into business practice and is a relevant subject of research. In this context, AM using pellets or granulates is a relatively new process that still needs to be explored. This process is sustainable because it supports the elimination of energy-intensive process steps such as filament production. It also opens up new design possibilities because it can process much larger amounts of material per time than many conventional additive manufacturing processes. The aim of this paper is to compare this Fused Granulate Fabrication process with the filament-based Fused Filament Fabrication process and to discuss potential applications on the basis of specific advantages and disadvantages. Both filament-based and pellet-based additive processes are compared and evaluated on the basis of technical criteria, sustainability and cost. The evaluation has shown that pellet-based processes have some advantages in terms of sustainability and material selection. These advantages are offset by disadvantages in terms of processing. This analysis therefore provides a basis for the selection of a suitable process based on various criteria.

Additive manufacturing (AM) processes are becoming increasingly important alongside conventional processes. As a result, the consumption of materials is also increasing. The most widespread process in polymer AM is Fused Layer Modelling (FLM). Today, the FDM process often uses synthetically produced materials based on petrochemical processes. However, there is little knowledge about which bio-based and recycled polymer materials are suitable for sustainable polymer AM. The aim of this paper is to carry out investigations of eight selected materials, which are already commercially available, to gain insights into their suitability as materials for polymer AM. These materials are divided into four categories: conventional, recycled, bio-based and fibre-reinforced thermoplastics. The evaluation model consists of a point system in which the materials are evaluated according to various weighted criteria. For technical, economic and ecological evaluation meaningful criterions were developed and applied. Based on the evaluations, three two-dimensional strength diagrams were developed, from which the results of the materials, on two of the evaluations in each case, can be read. These results are combined in a three-dimensional diagram. This representation provides the ability to make a precise selection of bio-based or recycled materials for polymer AM.

Additive manufacturing (AM) has become increasingly popular in recent decades and is now used in many fields. This increases the need for lectures and courses at universities to provide future engineers with the necessary knowledge for product development and design for additive manufacturing (DfAM). In this paper, a “rapid prototyping workshop” is presented to provide students with the technical and design skills for product development using additive manufacturing. In this workshop, this knowledge is imparted by means of the development of an unmanned aerial vehicle (UAV). Based on a literature review, the state of the art will be analyzed using previous approaches to integrating additive manufacturing into teaching using UAVs. Subsequently, a new approach is presented in which two groups of Master's students design and additively manufacture a UAV. The students learn a methodical approach to adapt the design of the UAV's components to different requirements, to connect the components and to select suitable materials. The implementation of the new design will use different tools, such as morphological box and finite element simulation. The results show the successful implementation of two different design approaches in compliance with the requirements. Assessment of the learning outcomes of this course will be through student feedback.

Additive manufacturing technologies for plastics are typically used in industry for prototypes, presentation models and small batches but also additive tooling. Especially for low volumes, this manufacturing method offers a high degree of efficiency, since no special tools or fixtures are required, which leads to a significant reduction in manufacturing costs and manufacturing time. Up to now, applications have usually been made using only one material, as the use of different materials in a single printing process is a particular challenge. In this contribution, the state of the art for printing processes suitable for multi-material printing and associated application examples are first presented in a literature search. The focus of this contribution is on the fused layer modeling (FLM) process with experiments and analysis on the application of different materials (PLA, PETG, ASA and PC Blend). A 3D-printer with a single nozzle is available for the practical experiments. Due to an additional multi-material device this 3D-printer is capable of processing up to five different materials in one printing process. Colorful presentation models are the first step to gain experience in multi-material printing. The investigation will then be extended to include the combination of different materials. For this purpose, standardized plastic tensile specimens are additively manufactured and subjected to tensile testing in order to analyze material properties. The tensile specimens are manufactured in different patterns and material combinations. This results in measurements that allow a comparison with the initial materials. In addition, the challenges in the printing process, material selection and material arrangement are demonstrated. In order to develop a functional multi-material component, sufficient fusion in the bonding layer between the materials must be ensured.

4D printing is the next step in additive manufacturing. Magnetoresponsive materials facilitate the creation of gripping tools through 4D printing, allowing for structural changes in response to external stimuli. In this study, the structural change is manifested as motion, triggered by an external magnetic field. This technology offers significant advantages in medical and industrial applications, including the printing of life-like moving organ models for medical training and the development of actuators for use in explosive environments. Magnetoresponsive materials are programmed with a magnetic profile and actuated by an external magnetic field. A compound of strontium ferrite microparticles SrFe_12O_19 ( ≤ 20μ m ) and an elastic polymer (thermoplastic copolyester) with a Hardness of Shore D 40 was produced. A star-shaped body was programmed and actuated by two permanent magnets, each of B_r=1.29 - 1.32T . As there is no analytical approach for calculating the required actuation flux density, one has been developed. The approach is verified experimentally by using a Hall probe. It is appropriate to set the field with a Helmholtz coil, despite the utilization of two permanent magnets. The use of a commercial fused filament fabrication printer for the processing of magnetoresponsive materials has been realized here for the first time. The main contributions are the short time constant (around t_a=0.1s ) for actuation and the repeatability (around n=200 actuation cycles) of the motion. The feasibility of multiple diverse reprogramming is a step forward in 4D printing. Hence, the post-print programming and the inhomogeneity of the field limit the ease of the presented method.

PurposeThis study aims to investigate a systematic approach to the production and use of additively manufactured injection mould inserts in product development (PD) processes. For this purpose, an evaluation of the additive tooling design method (ATDM) is performed.Design/methodology/approachThe evaluation of the ATDM is conducted within student workshops, where students develop products and validate them using AT-prototypes. The evaluation process includes the analysis of work results as well as the use of questionnaires and participant observation.FindingsThis study shows that the ATDM can be successfully used to assist in producing and using AT mould inserts to produce valid AT prototypes. As a reference for the implementation of AT in industrial PD, extracts from the work of the student project groups and suitable process parameters for prototype production are presented.Originality/valueThis paper presents the application and evaluation of a method to support AT in PD that has not yet been scientifically evaluated.

Dieses Buch ermöglicht dem Anfänger in der 3D-Modellierung einen schnellen Einstieg in die Arbeit mit dem neuen CAD-System Onshape. Dazu wird als einfaches Übungsbeispiel ein Automobil mit Ballonantri