Shahin Rahimifard

A decision-making model for waste management in the footwear industry

The footwear industry, over the last years, has placed significant effort in improving energy and material efficiency, but in comparison little effort has been directed at the recovery and recycling of shoes at the end of their functional life. In reality, most worn and discarded (end-of-life) shoes are disposed of in landfills. Producer responsibility issues and forthcoming legislation as well as increasing environmental consumer demands are expected to challenge the way the global footwear industry deals with its end-of-life waste. This paper presents an investigation into the steps required to consider the end-of-life implication of shoes and promote post-consumer recycling practices in the footwear industry. The paper describes the design and specification of a decision-making model to identify the most appropriate reuse, recovery and recycling option for post-consumer shoes. Such a tool in addition to supporting design and material selection processes could also provide benchmark information for the selection of a best end-of-life practice for a selected range of shoe types. The paper concludes by providing a case study for shoe waste management to demonstrate the practicality of this decision-making model.

Barriers, drivers and challenges for sustainable product recovery and recycling

There has been a significant growth in research and applications of product recovery and recycling over the last two decades, in particular with the view of recent product take-back legislation which has extended the responsibility of manufacturers to include the recovery and safe disposal of their products. However, at present, the global scale of product recovery applications is significantly disproportional to the total manufacturing output. Hence, to achieve the idealistic goal of ‘zero landfill’, there is a need to significantly improve and extend both the scale of product recovery activities and the range of manufacturing applications in which such activities have yet to be implemented. This paper examines a range of barriers, drivers and challenges in research and development for the next generation of product recovery initiatives. A range of existing applications and case studies undertaken for the UK market has been used to analyse issues related to: the need for improvement and expansion of current legislation on producer responsibility; product take-back and reverse logistic models for collection of used products; knowledge-based approaches for end-of-life considerations during the design phase; improved technologies and increased automation in pre- and post-fragmentation recycling processes and most importantly, the requirement for sustainable business models for establishing value recovery chains which can be based on the provision of services rather than products. The paper concludes by summarising the results of this analysis to bridge the gap between existing and future sustainable solutions for product recovery.

An end-of-life decision support tool for product recovery considerations in the footwear industry

The footwear industry is a manufacturing sector that utilizes a wide variety of materials and processes to produce a range of distinctly different products, from sandals to more specialized footwear. Currently, more than 19 billion pairs of shoes are produced worldwide every year. This creates a large waste stream at the end of the functional life of shoes, which are often disposed of in landfills. Producer responsibility concerns, forthcoming legislation and increasingly environmentally conscious consumers are expected to challenge the way the global footwear industry is dealing with its end-of-life (EoL) products. This paper highlights the potential benefits of developing a footwear product recovery methodology and an associated software tool to support decision-making to determine the most suitable (in environmental, economic and social–technical terms) manner in which to treat post-consumer shoe waste. Such a methodology, in addition to supporting design and material selection processes, could also provide benchmark information for the selection of the best EoL practice for a selected range of different shoe types. The paper concludes by providing a computational viewpoint of an EoL shoe recovery decision support tool.

Simulation of energy consumption in the manufacture of a product

Energy rationalisation, the elimination of unnecessary energy consumption, is becoming increasingly important in a resource constrained world. The use of energy is a significant contributor to greenhouse gas emissions and much research has been done to reduce energy use in manufacturing. So as to enable the rationalisation of energy consumption, it is essential that it is understood where energy is being used. This paper describes the design and implementation of a simulation model that has been generated to support the modelling of energy consumption within manufacturing systems. The simulation model allows various ‘what-if’ scenarios to be investigated thereby enabling engineers to understand the impact of various manufacturing parameters on energy consumption and thus reduce reliance on energy and the production of greenhouse gas emissions.

Analytical methods for waste minimisation in the convenience food industry.

Waste creation in some sectors of the food industry is substantial, and while much of the used material is non-hazardous and biodegradable, it is often poorly dealt with and simply sent to landfill mixed with other types of waste. In this context, overproduction wastes were found in a number of cases to account for 20-40% of the material wastes generated by convenience food manufacturers (such as ready-meals and sandwiches), often simply just to meet the challenging demands placed on the manufacturer due to the short order reaction time provided by the supermarkets. Identifying specific classes of waste helps to minimise their creation, through consideration of what the materials constitute and why they were generated. This paper aims to provide means by which food industry wastes can be identified, and demonstrate these mechanisms through a practical example. The research reported in this paper investigated the various categories of waste and generated three analytical methods for the support of waste minimisation activities by food manufacturers. The waste classifications and analyses are intended to complement existing waste minimisation approaches and are described through consideration of a case study convenience food manufacturer that realised significant financial savings through waste measurement, analysis and reduction.

Modelling of post-fragmentation waste stream processing within UK shredder facilities

With the introduction of producer responsibility legislation within the UK (i.e., waste electrical and electronic equipment directive and end-of-life vehicles directive), specific recycling and recovery targets have been imposed to improve the sustainability of end-of-life products. With the introduction of these targets, and the increased investment in post-fragmentation facilities, automated material separation technologies are playing an integral role within the UKs end-of-life waste management strategy. Post-fragmentation facilities utilise a range of purification technologies that target certain material attributes (e.g., density, magnetism, volume) to isolate materials from the shredded waste stream. High ferrous prices have historically meant that UK facilities have been primarily interested in recovering iron and steel, establishing processing routes that are very effective at removing these material types, but as a consequence are extremely rigid and inflexible. With the proliferation of more exotic materials within end-of-life products, combined with more stringent recycling targets, there is therefore a need to optimise the current waste reclamation processes to better realise effort-to-value returns. This paper provides a background as to the current post-fragmentation processing adopted within the UK, and describes the development of a post-fragmentation modelling approach, capable of simulating the value-added processing that a piece of automated separation equipment can have on a fragmented waste stream. These include the modelling of the inefficiencies of the technology, the effects of material entanglement on separation, determination of typical material sizing and an appreciation for compositional value. The implementation of this approach within a software decision-support system is described, before the limitations, calibration and further validation of the approach are discussed.

Integrating the CAx process chain for STEP-compliant NC manufacturing of asymmetric parts

Acceleration of product development, decrease of NC programming effort and increase of product quality are demands from enterprises to make their products competitive. These requirements are hardly met by the todays used CAx process chain which is based on a multitude of interfaces and the standardized control data format ISO 6983. New concepts of product data modelling are necessary for a structured and object-oriented description of machining. The development of STEP-NC (ISO 14649) over the last ten years has brought new opportunities for automating the CAx process chain. The present paper portrays a methodology for implementation of a standardized CAx process chain for rotational asymmetric parts, which are described in the technology-oriented process model for turning (ISO 14649-12). The methodology is realized through a suite of STEP-compliant NC software tools, based on STEP-compliant information models to integrate the whole chain from design to machining. Component case studies are used to demonstrate and analyse the methodology. The final part of the paper discusses the major issues and deficiencies related to the current phase of development of this new approach.

A responsive demand management framework for the minimization of waste in convenience food manufacture

Convenience food manufacture generates considerable waste through poor planning of production. This problem is particularly acute for products that have a very short shelf-life and will be disposed of as waste should their shelf life expire. Chilled ready-meals are convenience foods with relatively short shelf-lives and volatile consumer demands; their manufacture is based on forecasted volumes and when demand has been over-predicted, considerable wastes are created. This is referred to as overproduction waste (OPW), which typically sees finished products disposed of through commercial waste channels as a result of lack of demand. The research reported in this paper has investigated the generation of a responsive demand management framework for the reduction of OPWs.

Distributed scheduling to support mass customization in the shoe industry

The European shoe industry has experienced significant challenges in the last 20 years, mainly due to the pressures of modern global markets in which the industry has to compete with competitors from low labour cost countries in Asia and the Far East. A new trend is now forecast concerning the mass customization of shoes, where customers choose and order customized shoes from a range of predefined materials and designs. This is to be achieved through the ‘shoe shop of the future’ with combined capabilities of obtaining 3D models of customers feet together with the exciting developments offered through the latest advancement in e-commerce. However, such a novel approach for the customization of shoe design and production will have a significant influence on the batch sizes and expected lead times, and will reduce the average batch size of shoe production from 500–1000 pairs to about 10–20 pairs per batch. Consequently, customized shoes will result in an enormous increase in the number of batches, leading to an increase in the complexity of planning, scheduling and tracking of orders both across the supply chain and internally within various production departments of a shoe factory. This research proposes a distributed scheduling approach to provide the required autonomy in decision making and flexibility in job sequencing at departmental level to deal with the complexity of planning a large number of small batch production orders.

The adoption of STEP-NC for the manufacture of asymmetric rotational components

Abstract This paper reports ongoing research on the use of the evolving ISO 14649 standard, informally termed STEP-NC, which represents a new data model for the next generation of computer numerical controllers. The paper presents the major challenges in implementing STEP-compliant CAD/CAM (computer-aided design/manufacture) systems for manufacturing asymmetric rotational parts. It also discusses the need for a new ISO 14649 schema specific for asymmetric rotational parts and outlines a feasible solution to use the ISO 14649 data model for turn/mill machining.