Barbara Willems

Improvement Potential for Energy Consumption in Discrete Part Production Machines

Industrial production inevitably results in an environmental impact. Energy consumption is responsible for a substantial part of this impact. Currently, machine designers spend little attention to minimising the energy consumption, since their primary focus is on the well-functioning of the machine.

Can large-scale disassembly be profitable? A linear programming approach to quantifying the turning point to make disassembly economically viable

It is widely recognized that disassembly-based product End-of-Life strategies, such as component reuse or simple fraction material recycling, are environmentally beneficial. However, current disassembly costs hinder a widespread application of these strategies. This paper quantifies the disassembly time reductions required to achieve economic feasibility of systematic product disassembly. A modelling framework, based on linear programming, is used to investigate the effect of reducing the expected disassembly time and cost on the selection of the optimal End-of-Life strategy. The problem is optimized from an End-of-Life treatment facility point of view. All findings are based on the Belgian cost and price information captured in spring 2004. The linear programming model shows that for small products from the Waste of Electric and Electrical Equipment (WEEE) category disassembly-based End-of-Life strategies will hardly become optimal, while for medium- and large-sized products, this scenario can be made optimal if a substantial disassembly time reduction is achieved. Possible strategies to realize such reduction are briefly sketched.

The eco-efficiency of reuse centres critically explored - The washing machine case

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 worn-out products and technological progress embodied in new products, lifetime extension of old products is not always the most beneficial scenario from an environmental nor an economic point of view. This paper investigates this trade-off for the case of washing machines in a Belgian context. 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.

Design for active disassembly (DfAD): an outline for future research

Although active disassembly is an expanding research topic, no dedicated methodology for developing joining elements suitable for self-disassembling products has been described yet. Therefore, this paper presents a framework joining vital factors for developing new joining elements to be designed into self-disassembling products. The framework covers issues related to the authorisation level, the flexibility of product structures, the product functionality and the degree of restrictions during the design process.

Active snap-fit development using topology optimization

To make disassembly cost-efficient, one-to-many fasteners are needed. These so-called active fasteners use advanced materials or structures as a catalyst for disassembly, allowing multiple assemblies to separate simultaneously after exposure to specific external triggering conditions. Using topology optimization this paper explores the alternative configurations of pressure-based active fasteners. The optimization problem is first solved in the 2D space for a snap-fit like design. Based on these results the problem was extended to 3D and solved. Similar as for the 2D results, a detailed finite element verification was conducted which proved the optimized structure shows an increase of the disassembly efficiency with 200–250% compared to the initial non-optimized structure measured in displacement of the snapping features. As such, this paper shows that for future manufacturing businesses, active fasteners promise to be a valid alternative for shredding. Since the model can easily be modified for other trigger conditions or design configurations, the proposed approach proves to be suitable to develop different types of one-to-many disassembly fasteners.

A method to assess the lifetime prolongation capabilities of products

To achieve a sustainable growth, it is necessary to pursue the decoupling of economic welfare from the use of virgin resources: a shift from a linear economy to a closed-loop economy is required. Consequently, adaptation processes such as maintenance, repair, upgrading and remanufacturing are needed. This paper presents a dedicated method to assess the lifetime prolongation capabilities of products by evaluating their design. The method determines the suitability of a product to undergo adaptation processes and the improvement potential within the design of a product, its components and joints, using an aggregated metric.

Pressure-triggered active fasteners: Design results using topology optimization

Using topology optimization this paper explores alternative configurations of pressure-based active fasteners. The 2D and 3D optimization problem is solved for a snap-fit like design. A detailed finite element verification is conducted, the theoretical designs are translated into producible components and preliminary concepts how to manufacture the designs are presented.

Systematic development strategy for structure based one-to-many disassembly concepts

To make disassembly cost-efficient, one-to-many fasteners are needed. These fasteners use advanced materials or structures as a catalyst for disassembly, allowing multiple assemblies to separate simultaneously after exposure to specific external triggering conditions. Using topology optimization this paper explores a systematic development strategy for structure based one-to-many disassembly concepts