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.@en

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.

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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.@en

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.@en

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%).

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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.@en

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.

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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.@en

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.@en

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.

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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.@en

Composite materials, in particular fibre reinforced polymers, present a challenge when reaching their end of life. Current recycling processes are unable to capture the high-end material quality, thus challenging (re)use of composite materials in a Circular Economy. Structurally reusing segmented parts of end-of-life products as construction elements has been demonstrated to provide a promising alternative. However, reflection on the consequences for the initial design of composite products is still missing. This study investigates the effect of the original product design on the recovery and reuse of composite products, taking wind turbine blades as case material. Construction elements were cut from a decommissioned blade and reused in a design study. Observations from the recovery and design process were connected to decisions made in the original product design. The insights were discussed with experts from the field of blade design. This resulted in identification of design aspects that enable multiple lifecycles of the composite material as construction panels, if considered during initial product design.

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Composite materials are an attractive material choice as they enable lightweight, low-maintenance products with a long lifespan. Recycling these materials, however, remains a chal-lenge. Homogeneous material composition and the use of thermoset matrices complicate repro-cessing, and result in low-grade recyclate. This means that closing the loop for these materials in a circular economy remains challenging, especially for glass fibre-reinforced thermoset composites. For a circular economy, products need to be designed to preserve product functionality, material properties, and economic value for as long as possible. However, recovery strategies, design aspects and their interconnectedness are currently largely unexplored for products containing fibre-rein-forced polymers. The aim of this study was to identify circular strategies and determine design aspects for products containing composites. To achieve this, we conducted a systematic literature review and consulted experts. The circular strategies are largely similar to generic circular economy strategies as far as product integrity is concerned. However, on a material level, we identified addi-tional approaches, the most notable of which is structural reuse, which preserves the material quality and thereby value. The design aspects were clustered and positioned along the product design process to support implementation. Finally, the strategies and design aspects we identified were brought together in a framework to support product design and design research for products containing composite materials in the context of a circular economy.

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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.@en

In the Integrated Product Design master’s at Industrial Design Engineering, there is a growing diversity in students. In recent years we increasingly noticed that diversity could lead to complications within the various student teams. Examples are miscommunication, frustration, and interpersonal conflicts. This growing diversity between the team members strongly appeals to their ability to deal with these complications in a constructive way. Via a KPI tracking system we kept track of team performance and we identified four aspects affecting the team dynamics within the Advanced Embodiment Design project team [1]. This paper presents the case study of one of the student design-teams which was highly dysfunctional in design approach and conflicting cultural differences. It made this group perform at a lower level. Theory U [2] and dialogue techniques [3] were an unfamiliar approach for student design teams. Interventions using generative conversations stimulated connectedness between the team members and improved the team dynamics. The use of culture mapping [10] proofed to be a valuable tool to bridge the culture gap. Although this case study only describes one student design team, the drastic improvements resulted in the team winning the iF Design Talent Award 2020. The findings are promising, and further research is needed to investigate the generalizability of these approaches for Industrial Design Engineering education.@en

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.

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Composite materials are an attractive material choice as they enable lightweight, low maintenance products with a long lifespan. But closing the loop for these materials in a Circular Economy (CE) is challenging, especially for thermoset composites. In a CE, products should be designed for minimal impact while preserving their environmental and economic value for as long as possible. However, design strategies for composite products in a CE are currently largely unexplored. Insights from literature on design for a CE as well as on composites recovery are combined to create a set of design principles for composites in a CE. In addition to well-known long life, lifetime extension and product recovery approaches, literature indicates the potential value of structural recycling. Structural recycling preserves most of the functional value of the product, which is largely lost in materials recycling. Experts from composites industry were interviewed in focus groups to further explore CE strategies and design principles for a set of reference products, such as car interior components. The resulting framework connects Circular strategies to design principles for composite products and supports design of new composite products for use, reuse and recycling in a CE.@en

The Disassembly Map is a modelling method which allows to visually represent the architecture of a product, describing disassembly precedence and dependencies of components and operations necessary for their complete non-destructive removal. It introduced new standard visual elements to communicate the influence of specific design features on disassembly tools, sequences and time. A first iteration of this method was created during a study focused on a single product group, vacuum cleaners [1]. This paper presents a further development, meant to improve its versatility for application in diverse product groups. This was developed and tested by analysing four products (pressurized steam generator, coffee maker, child car seat and washing machine). This study shows the versatility of the Disassembly Map and introduces a new coding of action blocks, that allows the representation of a more extensive range of disassembly actions.@en

In the IPD masters in Industrial Design Engineering (TU Delft) we see a growing diversity in students. In recent years, the number of international students has grown to more than a third. Besides nationalities we also see differences in prior education, socio-emotional aspects and competences. In one of the masters courses Advanced Embodiment Design (AED), students work in teams on a client-based design project for one semester (21 European Credits). The student teams are supervised by coaches on a weekly basis. In recent years we increasingly noticed that the differences in background can lead to complications within the various teams. Examples are communication confusion, frustration and sometimes interpersonal collisions. There is a growing gap between the team members on cognitive and socio-emotional aspects and their ability to deal with this constructively. Within our team of coaches, we therefore focus mainly on keeping teams functioning in a healthy way and to a lesser extent on content and project results. With this course we want to offer students the opportunity to experience and perform in a successful team, acknowledge every student input and experience a successful result. To implement this vision and support our student teams, we started out with a project-group tracking-system using key performance indicators (KPIs). The KPIs gave the group of coachs insights in the performance of their own student groups relative to that of other groups. With this tracking system we could quickly pinpoint troublesome groups and individuals, which were used to lead our discussions during weekly coach meetings. During our weekly meeting we only discussed troublesome groups and tried to come to applicable solutions which could be implemented immediately. The solutions were found in literature, experiences within our own coach team, and making use of external experts. This paper presents our findings on improving multi-diverse team-performance by close tracking of their performance. We will focus on three major aspects of our findings: measuring student projects performance during the course, our experience and dealings with diversity in student teams, and on how the collaborating coach-Team helped in maximizing student-Team performance.@en