The traditional approach of teaching engineering at the faculty of Industrial Design Engineering using direct instructions and problem-based learning was ineffective, as students failed to apply the engineering knowledge in their capstone design projects. Therefore, in the first-year engineering course Understanding Product Engineering (UPE), the Productive Failure (PF) method is used to teach mechanics of materials. Amongst other subjects, UPE includes modules on manufacturing techniques for plastics and metals, typically taught by theory alone. To address the challenge of practicing this knowledge and enhance their learning even more, a simple, safe, and cost-effective machine was introduced simulating thermoforming, injection moulding, and metal bending. This machine encourages experiential learning, which positively impacts knowledge retention and decision-making regarding material-manufacturing techniques.
To validate the student’s enhancement in learning, an A/B test is executed which compares the PF approach using the experiential machine with traditional direct instruction (DI). Group A (nine students) used the machine and struggled before receiving instructional materials, while Group B (nine students) received direct instruction first. The students were interviewed on their experiences after the workshop and tested online on the content.
Results showed significant differences in student perceptions and experiences. Group A, using the experiential machines, felt more confident, enthusiastic, intrigued, and engaged compared to Group B. However, test scores of the exam a week later showed little differences between the two approaches.

Introduction In the bachelor program of the faculty of Industrial Design Engineering, three courses on sustainability are offered. Sustainable Impact focuses on the basics of sustainability like ecodesign and LCA, Design for the Circular Economy focuses on circular business models and future design visions, and the Sustainable Transitions minor focuses on sustainable systems interventions. Although these courses score “more than satisfactory” on student evaluations (EvaSys), attendance is low and decreasing over the course. Besides, coordinators of the parallel running design projects notice that students struggle with the integration of sustainability into the design solutions. To make sustainability more applicable, we developed a new master elective related to design for repair, named Repair! (ID5422, 3EC over 8 weeks). In this course we explicitly implemented the theory of productive failure by Kapur & Bielaczyc (2012) and followed the course-design model for productive failure described in Persaud & Flipsen (2023). Contrary to traditional teaching, productive failure flips the process and starts with an explorative problem which students cannot solve without the right knowledge. This is followed by an instruction explaining the missing concept and filling the knowledge gap, after which students apply their learnings on their own project. This approach engages students in active problem-solving, with the goal to increase retention of the theoretical concepts and facilitate deep learning. In the Repair course respectively 24 and 36 students participated over the past two years. Students work on client-based products, focusing on a demonstration model to show the improved fit of the product within a circular economy. In this paper, we will present the course and its content, one of the workshops explaining the productive failure approach, and finalize with an analysis of the student’s learning experiences.

Design for the Circular Economy often emphasizes business models and future visions, with less focus on practical application. Sustainability courses are generally seen as complex, attendance is often dropping, and the knowledge is minimally integrated into design projects.
In 2022, a new course on Repair was introduced. This course aligns with repair and with other R strategies like refurbishing, remanufacturing, and recycling. To engage students, the productive failure pedagogy was implemented in 8 weekly workshops. This method starts with an unsolvable exploratory problem, motivating students to learn the necessary knowledge. Workshops cover product architecture, disassembly documentation, part prioritization, legislation, directives, and human factors in repair design. The course, a master elective, has seen 25 to 50 students per run, working on client-based products to demonstrate improved circular economy fit.
This is the second IDE curriculum course using productive failure. Student evaluations (20 respondents) rated the course highly, with an overall grade of 8.5 out of 10 and a teaching, coaching, and feedback score of 4.68 out of 5. Students were highly engaged in making the circular economy actionable.
The paper will present the course, student outcomes, and qualitative learning experiences, focusing on the experiential learning aspect and the effects of productive failure on engineering courses.

Is coaching student design teams a secret? Not really. But it is complicated and the best way to learn it is to dive in and be open. Experienced coaches put this cheerfully illustrated book together to help you recognise many coaching situations and the way to respond to them. The book provides tools as well as more than ten practical examples of team workshops. Moreover, it provides a system to efficiently manage extended coaching projects with more teams. Feel supported and get coaching.

With the introduction of the new IDE bachelor in 2021 all courses underwent a revision to promote, amongst other, an autonomous learning attitude. The conventional approach of teaching engineering relied on direct instructions and problem-based learning and proved to be inadequate, as students struggled to apply their engineering knowledge in capstone design projects. Based on our research none of the student’s applied mechanics and materials and only a handful referenced to materials and manufacturing processes in their capstone project. To align with the new approach and to increase the application of engineering in capstone design projects, “productive failure” was introduced as a new didactical approach within our first-year course, Understanding Product Engineering (UPE, IOB1-2). Productive failure flips the traditional learning process and starts with an explorative problem which students cannot solve without the right knowledge. This is followed by an instruction explaining the missing concept. The approach engages students in active problem-solving, with the goal to increase the retention time of the theoretical concepts. We have developed our education around this using our in-house developed framework which includes lectures, workshops, and instruction videos facilitating the seamless integration of this approach into our own courses but also to disseminate it among our academic peers. Based on literature productive failure seems to increase the retention time but is not tested in the context of engineering design. To evaluate the retention time of productive failure and to compare it with the conventional approach of direct instructions, we developed a test to measure students’ retention of the taught knowledge. During the second-year follow-up course of Product Engineering (PE, IOB3-5) we started with an in-class formative entrance-test. An online multiple-choice test was created using questions mirroring those from the first-year final exam. We asked students to do this test with the uttermost care and fill it in seriously without gambling an answer. Students always had the opportunity to tick off the “I don’t know” box without consequences. Of the 282 students performing this test, 16% were repeaters, and 14% were students which transitioned from the previous bachelor program, having never taken the first-year UPE course. This paper will present the outcomes of this test and our findings into the possible retention time of our approach. This study will be repeated annually, serving as longitudinal study of our engineering education to continuously assess and improve our didactical approach.

This paper introduces the Total Cost of Ownership Score (TCOS) as a comprehensive framework for evaluating and improving product repair, durability, and maintenance all together on a uniform scale. The scoring procedure, implemented through a spreadsheet, calculates a product's total cost of ownership per year based on likelihood of failure modes, repair costs per failure (parts, labor, and other), likelihoods of repair successes, and cost of replacing the product if repairs fail. Because costs and repair times vary substantially based on many factors, and likelihoods of device failures and repair successes are stochastic by nature, the uncertainties are large and must be displayed in final scores. However, preliminary results indicate that even with large uncertainties, the TCOS provides meaningful product comparisons and hotspot identification. The advantages of the TCOS include scoring quantitatively in units that both consumers and businesses understand and value, to drive market behavior; vast reduction of subjective judgments in scoring; measuring durability and repair on the same scale; universal applicability, enabling legislation or policy to scale across products easier; and enabling legislation to allow innovation rather than prescribing designs. The TCOS's two challenges are that the data required is not publicly available for most products, so it requires empirical product testing; and further development / negotiation is required to decide what standard assumptions can be applied as shortcuts to shrink the scope of empirical testing.

To make electronic products fit for circular economy strategies such as life extension, refurbishment, and recycling, ease of disassembly is a key design quality. Several tools are available to assess the ease of disassembly of products during the design process, such as the ease of Disassembly Metric (eDiM) and Hotspot Mapping (HSM). The eDiM method uses the time-to-dismantle as a unit for calculating the ease of disassembly. The longer it takes to reach a priority part, the lower the ease of disassembly. Hotspot mapping scores the different parts in the product architecture and ranks them on its failure rate (priority parts), activity, time-to-disassemble, embodied environmental impact, and embodied economical value. These tools help designers prioritize which parts of the product need to be redesigned to improve its circularity. The eDiM tool is quick and easy to use but is based on generic proxy times, which may not be applicable to specific fastener designs or product types. On the other hand, the hotspot mapping tool uses actual recorded times to accurately identify disassembly hotspots. Recording the time-to-disassemble is more accurate, but is also more time consuming and depends on the operator's experience. Therefore it is difficult to come up with reproducible numbers. It is crucial to find the right balance for these tools, to be able to accurately identify hotspots while maintaining the usability. In this paper, we research how to develop product-specific proxy times in order to reduce the effort required for assessing hotspots. To reach our goal, we conducted a series of experiments to measure the actual disassembly times of different computer mice, and compared them with the predictions from eDiM. The results indicate that the tools provide accurate results for the most dominant fastener type used in this type of product (Phillips screws) but largely deviate from actual results for some other common fastening techniques, such as adhesives. Consequently, generic proxy times could not be used to correctly identify the product design hotspots. The authors suggest specific modifications to the ease-of-disassembly tools to improve their applicability, thereby supporting the design of circular electronics.

The availability and storage of spare parts are the main barriers to product repair. One possibility would be to 3D print spare parts, which would also enable the repair of products not intended to be repaired. Besides manufacturers, 3D printing spare parts is an interesting option for self-repair by consumers. However, the digitisation of spare parts for 3D printing is a challenge. There is little guidance on how to make a 3D-printed version of the original part. This paper establishes a framework through a literature review and experimental study to describe how to use 3D printing to produce spare parts for repair. Additionally, qualitative data coding was used to find the influence of previous experience, process implementation, and part complexity on the overall success of the 3D printing for repair (3DPfR) process. Our study showed that the 3DPfR process can be described as an iterative design for an additive manufacturing process that is integrated into a repair process. Additionally, it was found that the incorrect implementation of process steps was the most important predictor of the repair result. The steps that were performed incorrectly the most were synthesising design concepts (64%) and validating print quality (also 64%).

Spare parts availability is crucial for extending the life of consumer products. However, long-term availability could lead to high stocks of spare parts, which might not be used. Instead, on-demand manufacturing of spare parts with additive manufacturing (AM) is a promising alternative. This paper presents a method to evaluate parts on their eligibility for AM spare parts. The parts evaluation is based on AM technology accessibility as well as part requirements. This method was tested by assessing all parts of the Dyson V11 broom-stick vacuum-cleaner and validated by printing and testing a selection of parts. For this, both plastic and metal spare parts were made through fused deposition modelling (FDM), stereolithography (SLA), binder jetting (BJ), material jetting (MJ), selective laser melting (SLM), selective laser sintering (SLS), and multi jet fusion (MJF), using both desktop FDM printers and off-site service providers. Based on these results, we conclude that currently only a small number of parts can be replaced by additive manufactured parts without considerable redesign efforts. AM parts can compete on price with the current stocked parts, but may be more expensive for other products. We also identified additional functional requirements for evaluating the eligibility of a spare part for AM.

In September 2021, the faculty of Industrial Design Engineering (IDE) introduced a revamped bachelor's programme that emphasizes design for higher complexity, teacher as a coach, and autonomous learning. The programme includes Understanding Product Engineering (UPE), which teaches first-year design students about product embodiment, manufacturing, and mechanics of materials. However, the traditional approach of teaching engineering using direct instructions and problem-based learning was ineffective, as students failed to apply the engineering knowledge in their capstone design projects. To address this issue and promote autonomous learning, the Productive Failure (PF) pedagogical framework was introduced as the main pedagogical framework in UPE. However, the general approach of the PF pedagogy as described by Kapur, lacked a translation into an effective design of the workshops. To address this, this paper proposes a hands-on model based on constructive alignment, where learning objectives, activities, and assessment are designed side-by-side. This paper presents our didactical model, which was developed in an agile way during the second run of UPE. The hands-on model proposed aids in applying the PF pedagogy in engineering courses and consists of a method to develop workshop assignments and a didactical approach to guide and coach students through the workshop process.

Elke keer dat Bas Flipsen meedoet aan het Repair Café in zijn woonplaats stuit hij op schroeven die moeilijk toegankelijk zijn omdat ze diep in een product verborgen zitten. ‘Ik raad iedereen aan die met circulariteit bezig is, zowel studenten als professionals, om aan repair cafés mee te doen’, zegt hij. ‘Want daar ervaar je hoe slecht productontwerp repareren bemoeilijkt.’ Het is een van de redenen waarom hij veel van zijn onderzoekstijd besteedt aan het begrijpen van demontage en het ontwikkelen van methoden die van pas komen bij product(her)ontwerp.

In September 2021 the faculty of Industrial Design Engineering has implemented a completely revised bachelor. Important differences between the old and the new bachelor are its focus on design for higher complexity, the teacher as a coach, and the need for students to learn in an autonomous way. Within the bachelor, first year engineering students are introduced to the world of physical embodiment of products. This includes materials and design, manufacturing techniques, functional analysis, product architecture and mechanics modelling. In the past years we used a classical approach in teaching mechanics of materials using direct instructions and problem-based learning as the learning approach. Unfortunately, many design coaches observed that the acquired engineering knowledge was applied superficially or even left out of scope in students' design projects. The complete overhaul of the bachelor and the seemingly short retention of topics related to product engineering, made us change our learning approach from Direct Instruction to Productive Failure (PF). Making mistakes is an important condition for learning, and Productive Failure incorporates this while promoting autonomous learning. In essence, Productive Failure is a method that fosters effective learning and fits very well with a general design approach of iterative and explorative learning. During the development of UPE, we designed several workshops in a PF kind of fashion and applied it in the 2021 course. During the run we came across several hurdles in teaching, related to workshop design, and the impact of changing learning culture, and the teachers' role. This paper will discuss our findings when applying Productive Failure in our own class which is used to improve the course and line up the educational team in becoming productive-failure teachers.

Most products require a redesign to be viable in a circular economy. For instance, by implementing design for disassembly, remanufacturing, recyclability, and using long-lived components. Typically, different solutions can be chosen to improve a products' circularity, and different strategies can be aimed at keeping the product, its components, and materials in the loop.
When developing products for a circular economy, designers and manufacturers want to assess their solutions and choose between alternatives early in the design process. This paper describes the Circularity Calculator, a tool that has been developed to help designers assess the potential resource circularity and value capture of products in the first design stages. The tool provides quantitative indicators that help determine whether and which circular strategies are potentially viable for the company.
This paper discusses the methodology behind the Circularity Calculator, which uses four KPIs that have been developed for assessment; a Circularity indicator, Value Capture indicator, Recycled Content indicator and a Reuse Index. We will explain how the dashboard interface is used to model a linear and circular product system which can be compared on its economic potential. The tool is illustrated with an example concerning the analysis of a household blender.

The Sharepair project aims to decrease the waste of electronic and electric consumer products and increase their useful life, by supporting repair communities and scaling up citizen repairs through digital tools. One of the focus areas of this project is to support the discovery or manufacturing of spare parts. With a 3D CAD model of a part and a 3D printer, repair communities could manufacture spare parts. This paper discusses the possibilities of identifying repairs, within repair communities, that can be met through 3D printed spare parts. To understand and identify these possibilities, the repair entries expressed in the Open Repair Database (ORD) from the Open Repair Alliance were examined. The analysis aimed to identify documented examples of repairs that have broken or missing parts, and estimate how many may be suitable for replacement by 3D printed versions. The ORD includes 41,874 repair data entries from 229 repair communities (Repair Café, Restart Project, Fixit Clinic, and Anstiftung) in eighteen countries. Repair entries include information such as product category, brand, model, repair status and notes regarding the repair process and result, all in different languages. The analysis identified a list of the most commonly repaired product categories, brands, and models, as well as an estimate that between 7.5% and 29% of products in repair cafes that are not repaired today could be repaired with 3D printed spare parts. The analysis also showed that the data and information about the repairs is inconsistent, open to interpretation and often too limited to precisely pinpoint opportunities for 3D printed spare parts. Specifying the product parts that need repair or replacement and their functional requirements would be key to a successful identification. Thus, the study proposes recommendations to improve the process of capturing repair information that specifies the repair needs that can be met by the use of 3D printing.

This guide takes the reader through the 3D Printing for Repair (3DP4R) process. It consists of guidelines and tools to create a 3D printable version of spare parts needed for a product repair. 3D printing a spare part is more than just printing the original part. Instead, it is an iterative process in which the part is analysed, redesigned, manufactured, and tested, in order to come to a final part. This guide will describe these four phases in detail. The guide is meant for anybody who is interested in trying to manufacture spare parts with 3D printing technologies, remakers, tinkerers, volunteer repairers, professional repairers, and everyone who is interested in repair initiatives.

In our Integrated Product Design master at the Delft faculty of Industrial Design Engineering we see a growing diversity in our student population. Besides a growing number of different nationalities there are also significant differences in prior education, competences, and socioemotional aspects. Within the Advanced Embodiment Design (AED) course, students work in teams on a client-based design project for one full semester. In 2018-2019, 22 student-teams started out their endeavour, coached by eight coaches. Within the course an important learning objective we want to offer students is the opportunity to experience and perform in a successful team, acknowledge all students' input, and experience a successful result. During the process of embodiment design, the project teams come across several hurdles which challenges team performance and their project progress, and thereby influences the project results. To maximise the performance of student design-teams we have conducted two studies researching the challenges these teams come across over the course of the semester. One study was based on the coaches' experiences during the project (Flipsen & Persaud, 2016), and the other one on the students' individual reflections on the project (Flipsen, Persaud & Magyari, 2021). The challenges our students come across are analysed and relate to becoming a team, doing the project right, and finalising the project successfully. The results of both studies are used to develop a framework supporting coaches in maximising the performance of multi-diverse design teams. The framework is built around the Theory U (Scharmer 2016), a model describing how teams work with each other, following the right path to success (presencing) or off-tracking by muddling through, or by absencing. To track the different team's performances, we use a project-group tracking-system existing of seven Key Performance Indicators combined with a coach journal. The combination of KPI's help the team of coaches to pinpoint lower performing teams and intervene when needed. In this paper we will present the framework, consisting of (i) preparatory activities to initiate trust, teambuilding, and a successful student cooperation, (ii) a system to track the student-teams' health and performance and pinpoint troublesome groups, and (iii) responsive activities related to the hurdles teams might come across and how to reverse them. To assist the individual coach, we have developed several responsive activities the coach can use to intervene, slowing down the process of dysfunctionality and revert the process towards highly performing teams. The activities are tested in the two cohorts following our initial studies in 2018-2019.

In the IPD Master’s in Industrial Design Engineering (TU Delft) we see a growing diversity of students. We see the international student population growing, but also see significant differences in prior education, socio-emotional aspects, and competences. Within the Advanced Embodiment Design (AED) course, students work in teams on a client-based design project for a full semester. In 2018-2019, 22 student-teams started out their endeavour, coached by eight coaches. On a weekly basis the coaches tracked the teams' performances by means of six key performance indicators. The weekly logs are aggregated, converted, and visualized in a performance dashboard which was used to lead the discussion on troublesome teams and solutions to get them back-on-track. In this cohort four fields were found: (i) cultural differences; (ii) differences in design approaches; (iii) emotional differences; and (iv) differences in student competences. These typical problems were the result of our own coaches' perspective, and not so much from a student's perspective. To really get a grip on team dynamics and issues involved, we wanted to know what students come across when functioning in a multi-diverse team. In this paper we present our exploration from students' perspective by evaluating the end-of-course reflections. The goal of this research is to learn about the most occurring issues within multi-diverse teams and come to applicable solutions to help teams during the project. We started out with a word cloud to find the most common terms and use those as labels for clustering. 308 unique students’ quotations were labelled and clustered into three main clusters based on project management, emotional interaction and interdisciplinary, and 11 subclusters. The clustered data revealed interesting results in terms of (sub)clusters as well as their relationships to each other. Visualizing the associations between the subclusters show for example that lack of clear consensus on leadership causes challenges from various aspects leading to difficulties in role agreements, task concerns and design approaches, as well as managing individual behaviours. Despite initial assumptions, Cultural Differences led to the smallest number of challenges but scored high in terms of relations with other clusters. In this paper we will present our findings on the issues clustered and the prioritization of importance. We will discuss the relationships between the clustered student challenges, and review solutions which can help them out in becoming highly performing teams.

Composite materials offer many advantages during the use phase, but recovery at the end of a lifecycle remains a challenge. Structural reuse, where an end of life product is segmented into construction elements, may be a promising alternative. However, composites are often used in large, complex shaped products with optimised material compositions that complicate reuse. A systematic approach is needed to address these challenges and the scale of processing. We investigated structural reuse taking wind turbine blades as a case product. A new segmentation approach was developed and applied to a reference blade model. The recovered construction ele- ments were found to comply to geometric construction standards and to outperform conventional construction materials on specific flexural stiffness and flexural strength. Finally, we explored the reuse of these construction elements in practice. Together, the segmentation approach, structural analysis and practical application provide insights into design aspects that enable structural reuse.

Designers and engineers need better tools and methods to create highly repairable products. Design for disassembly and reassembly is an important product related design feature that can enhance repair. In a highly repairable product, the components that fail most often should be easily accessible for repair or replacement. This paper describes the development of a method to visually map the disassembly of a product, showing different routes towards target components. These components can be those with a high potential failure rate (important for repair), embodied environmental impact (important for recycling) and economic value (relevant for component harvesting), depending on the circular strategy under consideration. The ‘Disassembly Map’ method is set up to guide product design and is aligned with the most recent research and standards on product repairability. The ease of disassembly is assessed on Four main design parameters are considered in this method to assess the ease of disassembly of: disassembly sequence/depth, type of tools, fastener reusability/reversibility, and disassembly time. In contrast to most of the related literature found, the Disassembly Map method is not based on the use of an algorithm for the automatic calculation of optimised disassembly sequences. It asks designers and engineers to analyse each disassembly step using standardized visual elements based on the ease of Disassembly Metric (eDiM) and the Maynard Operation Sequence Technique (MOST). Insights gathered from this analysis and the resulting visualisation can be used in an iterative product development process. The method was developed by analysing seven vacuum cleaners. Its effectiveness was then tested by redesigning one of them, enhancing its repairability.