Keywords

1 Introduction and State of the Art

Nowadays, policies and decision-making focus more and more on ecological sustainability. This becomes evident when looking at the Green Deal of the European Union including major CO2-taxation. Additionally, ecological sustainability is listed in the top 4 of main goal of the European Council [1]. Societal and economic impacts of an environmental friendly transformation in technology frame ecological changes [2, 3]. Besides that, new manufacturing technologies and process chain designs emerge and allow to push the boundaries regarding geometries and product quality features. Metal Additive Manufacturing (M-AM) is a famous example in this field. Especially, Laser Powder Bed Fusion (L-PBF) increases its value for industrial application throughout numerous studies on materials, their properties and secondary effects [4]. By joining both the trends, AM and sustainability together, research output increases tremendously during the last ten years, which is shown in Fig. 1.

Fig. 1.
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Number of publications found in Web of Science on 19th April 2022 with the query “sustainability AND additive manufacturing”

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There is a lack in the state of the art, regarding the wholistic approaches to the question, whether or not the L-PBF process is sustainable. Several studies focus on single aspects, acting like pieces to a bigger puzzle [5–7], whereas some papers judge L-PBF sustainable and others do the opposite. Consequently, various facts and circumstances have to be focused on to reach a final decision. Most advantages of AM in general lie in material saving potentials, reduction of storage and logistics, geometrical optimization opportunities and life-cycle performance regarding repair and adding functions to an existing part [7]. Challenges arise from the scope either only on production or on the whole life cycle [8], a lack in education, a lack in knowledge about part performance, expandable optimization in production flows [5] and high specific energies [6].

The complexity to answer the question, whether AM increases sustainability in manufacturing, advances again, if different parts or products are considered and if a second question on substitution of or supplement on conventional process chains rises. Not only is this a challenge to researchers looking for industrial use cases to study, but also for decision-makers in different industries.

Sustainability is often linked to ecological effects. However, a wholistic approach has to be multidimensional since, there are influences on economy inside an enterprise and (inter)national economics and on society in general as well as employees in a company and players in a project group [2]. A fourth optional dimension is technology itself [9].

Serious game is a term for games serving other purposes beyond entertainment. Under the guise of an entertaining game, societal or educational goals can be pursued [10, 11]. In this study, a serious game concept serves for academic education of engineering students, who participate in a simulation of the real world. The approach of matching games with learning objectives is commonly used in training of pilots, emergency medicine [11] or even in industrial environments [12]. Nevertheless, by literature research that addresses the subject specific purposes mentioned above could be found.

The Federal Institute for Vocational Education and Training in Bonn, Germany (Bundesinstitut für Berufsbildung, BiBB) acknowledges serious games as a method to assess complex issues in a safe environment and in an iterative or evolving manner [13]. Based on the information given in several references, the following list concludes the key features of a promising serious game [10–13].

  • Choose an attractive topic embedded in a plausible setup.

  • Define rules, assignments and goals with distinction between game production focusing on the architecture and game design focusing on in-game features.

  • Choose between Rigid-Rule-Games with fixed rules and settings and Free-Form-Games with more degrees of freedom during the game or blend both types.

  • Keep up with the flow and monitor the current state repeatedly

  • Be careful to acquire an unbroken documentation of both game production and game design

Content and development of “AM for Future!?” are mainly based on these key features. Especially it is built up in a frame differing in basic concepts, design and production of the game [10] – with several special issues explained closer in the following.

2 Basic Concepts and Design of “AM for Future!?”

2.1 Basic Concepts

The game “AM for Future!?” is played as a simulation of a project in metal industries, so one main concept is to depict a real situation in a fictitious game world as close to reality as possible. All content tasks in the game concentrate on solving the problem “switch to additive manufacturing or not, considering sustainability”. There are clearly defined learning goals with respect to the complexity of problem solving as well as the target group of master students in materials science and engineering.

The game is divided into three layers. One is the project layer in which the gaming takes place. The project has project members such as executive director, process planner and production manager, played by students. Besides that, there are two external consultants, played by two institute staff members. A suitable project management as well as competences in systems thinking, product- and process design are crucial soft skills. Therefore a “toolbox” is given as one part of the game plan. The second layer is understanding and explaining the game design. Students and game directors interact out of their real position as learners and teachers. The third layer is the game development and further development from a meta position. All people involved in the game serve all three layers. This layered concept is mirrored in the ongoing game production with the concept of a dynamic mixture between free-form-game and rigid-rule game.

One of the most important concepts and very special in “AM for Future!?” is that each given “company role” relates to one aspect of sustainability [Fig. 2]. The executive director mainly argues from economical aspects, the process planner from ecological and the production manager from social aspects. Conflicts between the aspects resp. Their evaluation in the given production system vs. alternatives of a production with additive manufacturing are an intended part of the game. Life cycle designs, the opportunity to repair products and recycling or second life concepts contribute to a smaller environmental footprint of a product [8], but to achieve technological sustainability, the processes and operational plans have to be capable and adjusted to new cycles. Throughout game production, the role of an external technology consultant is related to basic aspects of technological feasibility. Latest research work with a rather theoretical approach came to similar conclusions [9].

Fig. 2.
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Dimensions of sustainability as a part of the game, similar to [9]

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2.2 Design

The design of “AM for Future!?” is summarized in Fig. 3. Main design elements are learning goals, setting, tasks and toolbox. There are learning goals related to technological and sustainability expertise and more general ones related to system design and project work skills. In the “setting” the roles of the players are defined, product and conventional production processes are given. The “tasks” differ between the layers mentioned above: project tasks, gaming tasks and tasks to further develop the game. The design element “toolbox” represents the model and methodical base for project work. It is inspired by the systems engineering approach of Haberfellner et al. [14] and decision making in complex situations [15, 16].

Most of the design elements are described in the game plan. Besides there are several documents with technical, calculatory and other methodical information. MS TEAMS is used as digital platform for communication and cooperation as well as for ongoing documentation.

Fig. 3.
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Design elements of “AM for Future!?”

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3 Iterative Research and Development

So far, there were three game cycles in three study semesters with a fourth iteration running. Production of the game is an ongoing process of iterative research and development, shown in Fig. 4. In the first run it was almost a free-form game with tasks not only to find solutions for a possible new sustainable manufacturing but also to set up details for the initial situation, the toolbox and the roles. From the first run to the next were changes especially in the technological focus accompanied by changes in “setting” and “tasks”. Changes in the game design are based on role and game ruling experiences as well as the factual and methodical results from previous cycles. Regular reviews are part of the development tasks. Iterative development also involves additional information packages and digital tooling. Finally, there should be a modular game structure with fixed and variable elements, more rigid-ruled, but never completely ruled, in newer versions than in previous ones.

Fig. 4.
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Production of the game

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4 Experiences and Results

With the experience of almost four game cycles, lots of recognitions were gained. The experiences and results are divided into two sections, a more technical one and a more methodical one.

Concerning the question “metal-AM facing sustainability: yes/no/depending?”:

  • L-PBF is only applicable from an economical point of view in high-end sectors with high requirements for geometrical complexity or aesthetic design.

  • The main sticking point in ecological sustainability is powder production and consumption of electrical energy. L-PBF could be more environmental friendly, if research and industry addresses those two issues towards higher degrees of efficiency.

  • Operators must face intensive training since there is no training profession in the field of AM, at least there is currently no such profession in Germany. However, jobs are rather not threatened by AM.

  • Sustainability aspects raise a conflict of objectives. On the one hand, integral design is an argument pro AM due to the ability for functional integration and less joints in a product. On the other hand, for the sake of reparability, differential design is recommended. The question which design method applies in what degree, depends on each specific case.

  • Evaluation strongly depends on defining systems resp. System borders (given system and the AM alternatives) and on the weight of different aspects.

Concerning basic concepts, design and production:

  • Balance between a clear setting and the freedom to follow ideas while playing is a key feature to a successful serious game in education.

  • The portions of blending Rigid-Rule-Game and Free-Form-Game together can change upon iterations and should be adaptable to the audience, learning goals and tasks in a modular approach with complementary design elements.

  • Game supervision should act neutral and steer only if necessary. If consultation is required, prescribe consultants into the setup.

  • Expert knowledge should be available in the background and should answer the demands of a student group. Immediate access to all kinds of information overextends students and blurs the games focus.

  • Always distinct between what is game related and what are technical issues. In a project meeting everyone should be clear, whether one is acting in his or her role of the serious game or whether one is being him- or herself.

  • Decisions to solve the given problem(s) should be based on a mix of suitable criteria, to be calculated resp. Evaluated by a complementary mix of clear quantitative methods, expert knowledge, results of literature research and intuition of the decision-making individual and team.

5 Summary and Future Studies

Naming and evaluating aspects of sustainability for a technical system mostly depends on decision making in a complex surrounding. This is what it is in the serious game “Additive Manufacturing for Future!?”. Before starting the cycle of serious games, there was the literature-based idea that M-AM enhances overall sustainability of a process chain, even though some papers reject this hypothesis. Several runs of the game proved that a final answer to this question is very complex to reach. Additionally, it took these several game runs to figure out the relevance of basic technological feasibility criteria – finally leading to a fourth dimension of sustainability. Variation in system boundaries could change the project results as well as shifting the focus within the four dimensions. Monitoring on the fly and after each game run showed that learning goals were accomplished.

Future studies could cover other technical products and other constellations within the fictitious enterprise. This allows a parametric study with a variation of individual influences due to different players and different roles. Additionally, more information on how to place M-AM in industry and what kind of products it is suitable for could be gathered. Regarding the game further improvements, maybe with enhanced interdisciplinarity with expertise in the field of psychology, social sciences or didactics, could improve the game itself, its attractiveness and the reliability of scored results. On the whole, improving this serious game towards a modular system with adjustable content, helps future and present-day decision-makers educating their judgement.