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Due to globalization and the resulting increase in competition on the market, products must be produced more and more cheaply, especially in series production, because buyers expect new variants or even completely new products in ever shorter cycles. Injection molding is the most important production process for manufacturing plastic components in large quantities. However, the conventional production of a mold is extremely time-consuming and costly, which creates a contradiction to the fast pace of the market. Additive tooling is an area of application of additive manufacturing, which in the field of injection molding is preferably used for the prototype production of mold inserts. This allows injection molding tools to be produced faster and more cheaply than through the subtractive manufacturing of metal tools. Material Jetting processes using polymers (MJT-UV/P), also called Polyjet Modeling (PJM), have a great potential for use in additive tooling. Due to the poorer mechanical and thermal properties compared to conventional mold insert materials, e.g. steel or aluminum, the previously used design principles cannot be applied. Accordingly, new design guidelines are necessary, which are developed in this paper. The necessary information is obtained with the help of a systematic literature research. The design guidelines are mapped in a uniform design guide, which is structured according to the design process of injection molds. The guidelines do not only refer to the constructive design of the injection mold or the polymer mold insert, but to the entire design process and describe the four phases of planning, conception, development and realization. Particular attention is paid to the special geometric designs of a polymer mold insert and the thermomechanical properties of the mold insert materials. As a result, design guidelines are available that are adapted to the special requirements of additive tooling of molds inserts made of plastics for injection molding.
Purpose
This 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/approach
The 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.
Findings
This 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/value
This paper presents the application and evaluation of a method to support AT in PD that has not yet been scientifically evaluated.
In 4D printing, an additively manufactured component is given the ability to change its shape or function in an intended and useful manner over time. The technology of 4D printing is still in an early stage of development. Nevertheless, interesting research and initial applications exist in the literature. In this work, a novel methodical approach is presented that helps transfer existing 4D printing research results and knowledge into solving application tasks systematically. Moreover, two different smart materials are analyzed, used, and combined following the presented methodical approach to solving the given task in the form of recovering an object from a poorly accessible space. This is implemented by self-positioning, grabbing, and extracting the target object. The first smart material used to realize these tasks is a shape-memory polymer, while the second is a polymer-based magnetic composite. In addition to the presentation and detailed implementation of the methodical approach, the potentials and behavior of the two smart materials are further examined and narrowed down as a result of the investigation. The results show that the developed methodical approach contributes to moving 4D printing closer toward a viable alternative to existing technologies due to its problem-oriented nature.
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.
In 4D printing an additively manufactured component is given the ability to change its shape or function under the influence of an external stimulus. To achieve this, special smart materials are used that are able to react to external stimuli in a specific way. So far, a number of different stimuli have already been investigated and initial applications have been impressively demonstrated, such as self-folding bodies and simple grippers. However, a methodical specification for the selection of the stimuli and their implementation was not yet in the foreground of the development.
The focus of this work is therefore to develop a methodical approach with which the technology of 4DP can be used in a solution- and application-oriented manner. The developed approach is based on the conventional design methodology for product development to solve given problems in a structured way. This method is extended by specific approaches under consideration of the 4D printing and smart materials.
To illustrate the developed method, it is implemented in practice using a problem definition in the form of an application example. In this example, which represents the recovery of an object from a difficult-to-access environment, the individual functions of positioning, gripping and extraction are implemented using 4D printing. The material extrusion process is used for additive manufacturing of all components of the example. Finally, the functions are successfully tested. The developed approach offers an innovative and methodical approach to systematically solve technical complex problems using 4DP and smart materials.
4D printing (4DP) is an evolutionary step of 3D printing, which includes the fourth dimension, in this case the time. In different time steps the printed structure shows different shapes, influenced by external stimuli like light, temperature, pH value, electric or magnetic field. The advantage of 4DP is the solution of technical problems without the need for complex internal energy supply via cables or pipes. Previous approaches to 4D printing with magnetoresponsive materials only use materials with limited usability (e.g. hydrogels) and complex programming during the manufacturing process (e.g. using magnets on the nozzle). The 4D printing using unmagnetized particles and the later magnetization allows the use of a standard 3D printer and has the advantage of being easily reproducible and relatively inexpensive for further application. Therefore, a magnetoresponsive feedstock filament is produced which shows elastic and magnetic properties. In a first step, pellets are produced by compounding polymer with magnetic particles. In a second step, those pellets are extruded in form of filament. This filament is printed using a conventional printing system for Material Extrusion (MEX-TRB/P). Various prototypes have been printed, deformed and magnetized, which is called programming. In comparison to shape memory polymers (SMP) the repeatability of the movement is better. The results show the possibilities of application and function of magnetoresponsive materials. In addition, an understanding of the behaviour of this novel material is achieved.
Experimental and numerical investigations into the forming of tailored strips and tailored tubes
(2008)
Through the application of tailored strips and tailored tubes, the wall thickness of components can be manufactured in a load-optimised manner. Thus, it is also possible to optimise component weight. Prior to the application of tailored products, wall thicknesses and the respective degree of deformation as well as the welding seam position can be determined in a FEM (finite element method) simulation. These results are then verified in test series on transfer presses and tube bending machines, with the necessary tool adaptations being determined in the process. This results in weight and cost reductions for deep-drawn components and tube sections. Moreover, this means that especially with regard to tubes, multiple sections can be combined in one component. A feasibility study shows that the level of possible weight and cost savings depends on the respective component geometry and load situation. Additional costs for the production of tailored products and - if necessary - tool modifications also need to be considered. Thus, the amount of savings possible for a part can only be determined on an individual basis.
Today, thermoforming moulds are mostly produced using conventional mould-building technologies (e.g. milling and drilling) and are made of metal (e.g. aluminium or steel) or hardwood. The tools thus produced are very robust, but are only cost-effective in mass production. For the production of small batches of thermoformed parts, there is a need for moulds which can be produced quickly and economically. A new approach which significantly reduces the production time and cost is the 3D printing process (3DP). The use of this technology to produce thermoforming moulds offers many new options in the geometries which can be manufactured, and in manufacturing time and costs. In a case study of a thermoformed part (a scaled automotive model), the pre-processing of the CAD model of a mould is demonstrated. The mould can be printed within a few hours, and is sufficiently heat-resistant for moulding processes. The important advantages of moulds printed in 3D, in comparison to moulds built using conventional technologies, are the ability to create any shape of channels for the vacuum and the simplification in the production of tool mock-ups. This paper also discusses the economics of the technique, such as a comparison of material costs and manufacturing costs in relation to conventional production technologies and materials.
Fusion 360 – kurz und bündig
(2022)
Dieses Lehrbuch ermöglicht dem Anfänger in der 3D-Modellierung einen schnellen Einstieg in die Arbeit mit dem cloudbasierten CAD-System Autodesk® Fusion 360TM. Der Schwerpunkt liegt dabei auf den grundlegenden Funktionen zur Modellierung von Einzelteilen und dem Zusammenbau von Produkten, sowie in der Erstellung von einfachen technischen Zeichnungen. Dabei werden bei jedem Schritt die besonderen Anforderungen an eine 3D-Druck-gerechte Gestaltung erläutert und umgesetzt. Somit ist das Ergebnis dieser „Schritt für Schritt“-Anleitung die vollständige Modellierung eines Miniatur-Automobils, das am 3D-Drucker in ein reales Modell umgesetzt werden kann. Das didaktische Konzept ist so ausgelegt, dass alle Schritte für ein Selbststudium geeignet sind.
In der vorliegenden Auflage wurde die Konstruktionsmethodik überarbeitet und einige Kapitel wurden ergänzt, beispielweise um das Erstellen von Teams.
Dieses Lehrbuch ermöglicht Anfängern in der 3D-Modellierung einen schnellen Einstieg in die Arbeit mit dem cloudbasierten praxisorientierten CAD-System Onshape. Dabei werden bei jedem Schritt die besonderen Anforderungen an eine 3D-Druck-gerechte Gestaltung erläutert und umgesetzt. Somit ist das Ergebnis dieser „Schritt für Schritt“-Anleitung die vollständige Modellierung eines Miniatur-Automobils, das am 3D-Drucker in ein reales Modell umgesetzt werden kann. Die vorliegende Auflage enthält nun eine Übersicht der 3D-Druckwerkstoffe und geht auf die aktuellen Weiterentwicklungen von Onshape ein. Die neue vereinfachte Anmeldung sowie die Erstellung einer Explosionsdarstellung werden in zwei neuen Kapiteln demonstriert.
Additive manufacturing offers completely new production technologies thanks to the layered structure and the simultaneous processing of several materials. In order to exploit the potential of this new technology, it is already necessary in product development to consider the components no longer as monolithic blocks, but as a structure of many layers and individual elements (voxels). Therefore, this paper will examine the current state of voxel-based CAD systems and the subsequent 3D multi-material printing of the designed components. Different voxel-based CAD systems are used and analyzed for component design and a sample component is additively manufactured. The results show that simple components can be designed using voxel-based CAD systems. With the application of 3D multi-material printing, different materials and thus functions can be assigned to the designed voxel-based CAD-model.
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.
This paper presents a method for supporting the application of Additive Tooling (AT)-based validation environments in integrated product development. Based on a case study, relevant process steps, activities and possible barriers in the realisation of an injection-moulded product are identified and analysed. The aim of the method is to support the target-oriented application of Additive Tooling to obtain physical prototypes at an early stage and to shorten validation cycles.
The integration of additive manufacturing processes into the teaching of students is an important prerequisite for the further dissemination of this new technology. In this context, the DfAM is of particular importance. For this reason, this paper presents an approach in which a connection is made between methodical product development and practical implementation by AM. Using a model racing car as an example, students independently develop significant improvements of particular assemblies. A final evaluation shows that the students have significantly improved their skills and competencies.
In the development of new vehicles, increasing customer comfort requirements and rising safety regulations often result in an increase in weight. Nevertheless, in order to be able to meet the demand for reduced fuel consumption, it is necessary within product development process to implement complex and filigree lightweight structures. This contribution therefore addresses the potential of generatively developed components for fiber-reinforced additive manufacturing (FRAM). Currently, several commercial systems for this application are available on the market. Therefore, a comparison of the systems is first made to determine a suitable system. Then, a highly stressed and safety-relevant chassis component of a race car is generatively designed and manufactured using FRAM. A matrix with short fiber reinforcement and additional long fiber reinforcement with carbon fibers is applied. Finally, tensile tests are carried out to check the mechanical properties. In addition, relevant properties such as weight and cost are obtained in order to be able to compare them with conventionally developed and manufactured components.
The use of architectural models is a long-proven method for the visualization of designs. More recently, powerful 3D printers have enabled the rapid and cost-effective additive manufacturing (AM) of textured architectural models. The use of AM technology to sample terraced houses in a specific use case (sampling center with more than 1200 customers per year) is examined within this contribution. The aim is to offer customers with limited spatial imagination assistance in the form of detailed architectural models of the whole house, which are divided into different modules. For this purpose, the structure of the terraced house is first analysed and examined for flexible design elements. The implementation of different variants of each floor should serve as a basis for the customer's decision on design and equipment. Thus, the architectural models are additively manufactured using Polyjet modeling. The necessary CAAD-data and interfaces, the technical possibilities and limits of this approach as well as the resulting costs are analyzed. The results of the AM process are evaluated to determine their applicability for the sampling of terraced houses. In addition, the evaluation will show that the additively manufactured architectural models will allow a more precise visualization of the building and thus a faster understanding of the design choices.
For some years now, additive manufacturing (AM) has offered an alternative to conventional manufacturing processes. The strengths of AM are primarily the rapid implementation of ideas into a usable product and the ability to produce geometrically complex shapes. It has also significantly advanced the lightweight design of products made of plastic. So far, the strength of printed components made of polymers is previously very limited.
Recently, new AM processes have become available that allow the embedding of short and also long fibers in polymer matrix. Thus, the manufacturing of components that provide a significant increase in strength becomes possible. In this way, both complex geometries and sophisticated applications can be implemented. This paper therefore investigates how this new technology can be implemented in product development, focusing on sports equipment. An extensive literature research shows that lightweight design plays a decisive role in sports equipment. In addition, the advantages of AM in terms of individualized products and low quantities can be fully exploited.
An example of this approach is the steering system for a seat sled used by paraplegic athletes in the Olympic discipline of Nordic paraskiing. A particular challenge here is the placement and alignment of the long carbon fibers within the polymer matrix and the verification of the strength by means of Finite-Element-Analysis (FEA). In addition, findings from bionics are used to optimize the lightweight design of the steering system. Using this example, it can be shown that the weight of the steering system can be drastically reduced compared to conventional manufacturing. At the same time, a number of parts can be saved through function integration and thus the manufacturing and assembly effort can be reduced significantly.
Today, Additive Manufacturing (AM) is an important part of teaching for the education of future engineers. Therefore, a variety of approaches have been developed in recent years on how to bring the design for additive manufacturing (DfAM) into university teaching. In a detailed literature review, the advantages and disadvantages of the previous approaches are considered and analysed. Based on this, an extended approach is presented in which students analyse and optimize a given product with respect to additive manufacturing. In doing so, the students have to solve challenging tasks in optimization in product development with the help of methodical approaches and practically implement their developed solutions with state-of-the-art additive processes. To work on this task, the students have two different 3D printers at their disposal, which work with different processes and materials. Thus, the students learn to adapt the design to different manufacturing processes and to consider the restrictions of different materials. The assessment of the results from this course is done through feedback and a written survey.
Systematische Erfassung von Einflussfaktoren für das Additive Tooling von Spritzgusswerkzeugen
(2021)
Additive tooling is a quick and cost-effective way of producing injection molded products and high fidelity prototypes using the injection molding process. As part of product development, additive tooling is integrated into a complex process. A lack of design and application knowledge represents a barrier in its use. The present work shows how a Design-Structure-Matrix (DSM) can be used to systematically record and analyze influencing factors and their interrelationships. A systematic literature search is carried out to identify the factors and relationships.