No abstract

By repairing and reselling used products, reuse centres aim at creating low-skill jobs while offering low-cost and environmentally beneficial products. However, due to a combination of decreased efficiency of wornout products and technological progress embodied in new products, lifetime extension of old products is sometimes not the most beneficial scenario from both an environmental and economic point of view. This paper investigates this trade-off for the case of washing machines. For selected types of washing machines, critical reuse ages are determined above which reuse is environmentally or economically undesirable. A sensitivity analysis shows that these critical reuse ages are often sensitive to small changes of the input parameters.

Increasing resource prices, ever-higher complexity of products, recent developments in legislation and the importance of a green brand image have resulted in an increased interest of original equipment manufacturers to facilitate a disassembly based end-of-life treatment for their products. The main reason is that precious metals, rare earth elements and plastics can be recovered with the highest yield and purity in a disassembly based treatment. However, original equipment manufacturers currently face several issues for the implementation of design for disassembly. To overcome these issues, first of all an in-depth analysis of design-for-disassembly opportunities and challenges is presented. Taking into account the results of this analysis, innovative low-cost elastomer-based fasteners have been developed, which can be simultaneously released by applying a sufficiently high force over a period of time. In addition, an experimental validation method was developed and adopted to demonstrate that the developed fasteners allow reducing the disassembly time by 70% to 90% for the housing of LCD TVs without compromising product robustness. The presented calculations indicate that the implementation of the developed fasteners is profitable from an overall perspective in regions with a labor cost higher than 7 €/h. However, original equipment manufacturers currently lack incentives to adopt design for disassembly for products sold in a Business-to-Consumer market, which are jointly collected and treated at end-of-life. Therefore, a differentiation in recycling fees proportional to the reduction in disassembly time is proposed to provide economic stimuli for original equipment manufacturers to implement these fasteners. Such a differentiation scheme, combined with the presented insights on opportunities to facilitate disassembly processes and the required resistance of fasteners to forces in function of time, will stimulate and enable the development of products which can be disassembled in an economically viable manner, resulting in improved material recovery from end-of-life products in industrialized regions.

No abstract

This paper presents a number of novel active fasteners developed to significantly lower disassembly costs during reconditioning, remanufacturing, and recycling of products. In the initial stage of the fastener development process, the applicability of distinct trigger signals for active disassembly (AD) is evaluated. Based on this evaluation, the high robustness of using a pressure increase or decrease as a nondestructive trigger for AD is demonstrated. Since previously proposed pressure-sensitive fasteners face considerable drawbacks upon implementation in electronic products due to the ongoing trend of miniaturization, a second generation of pressure-based active fasteners is developed. Evaluation of these fasteners by means of axiomatic design techniques and prototyping demonstrates that the presented snap-fits, which make use of a closed-cell elastomer foam, are most robust. Subsequently, the contraction forces that closed-celled foams can exert as a function of an increase in ambient air pressure are experimentally determined. Furthermore, the implementation of pressure-sensitive foam-based snap-fits in both a modem and a payment terminal is described. Results of these experiments demonstrate that the contraction force of a cross-linked metallocene polyethylene closed-cell foams can reach up to 6 N/cm 2 at an overpressure of 2 bar and that the foam-based snap-fits can be released at a pressure increase of 2 bar.