Fast and meta heuristics for part selection in flexible manufacturing systems with controllable processing times

This study addresses a part selection problem for flexible manufacturing systems in which part processing times are controllable to optimize the total cost associated with energy consumption, operational performance, and so on. The problem is to determine the set of parts to be produced, part processing times and the number of tools for each tool type in each period of a planning horizon while satisfying processing time capacity, tool magazine capacity and tool life restrictions. The objective is to minimize the sum of part processing, earliness/tardiness, tool and subcontracting costs. Tool sharing among part types is also considered. After an integer programming model is developed, two types of solution algorithms are proposed, that is, fast heuristics useful when decision time is critical and variable neighborhood search algorithms when solution quality is important. Computational experiments were conducted on a number of test instances and the best fast heuristics are specified, together with reporting how much the variable neighborhood search algorithms improve the fast heuristics.

A Review of Part Filtering Methods for Additive Manufacturing

As additive manufacturing (AM) increases in popularity, many companies seek to identify which parts can be produced via AM. This has led to new areas of research known as “part filtering”, “part selection”, or “part identification” for AM. Numerous methods have been proposed to quantify the suitability of a design to be made with AM, and each has its own benefits and drawbacks. This paper reviews popular methods of part filtering and elaborates on the advantages and disadvantages of the various approaches. The approaches for part filtering, and the example methods, are categorized and sorted along a continuum of opportunistic and restrictive methods in order to clarify use cases for various part filtering techniques. The approaches are also examined through the lens of specificity of process, as some are designed to be process agnostic, while others are customized for a specific AM technology or even a specific AM system. Finally, current gaps that exist in the part filtering research literature are discussed to help identify necessary and promising directions for future investigation.

Special Issue on Design and Manufacturing for Environmental Sustainability

This is the fourth special issue on design and manufacturing for environmental sustainability. While Japanese manufacturers are not so active in this field, the trend of integrating sustainability into manufacturing activities and management of companies is becoming dominant. We can point out three epoch-making instances: namely, United Nations’ ‘Sustainable Development Goals (SDGs),’ which consists of 17 goals to be achieved by 2030, covering not only environmental sustainability but also social and human sustainability; EU’s ‘Circular Economy,’ which promotes various routes for resource circulation (e.g., reuse, remanufacturing, maintenance, and recycling) for increasing employment and market competitiveness of EU and resource efficiency; and ‘Paris Agreement’ on climate change, which enforces reduction of the emission of greenhouse gases to zero by the end of this century. This special issue includes six well-written papers, all of which are deeply related to these three policies. The first four papers focus on product life cycle or even multiple product life cycles. This aspect is an inherent feature of design and manufacturing for environmental sustainability, which was not considered in traditional design and manufacturing. The keywords of these four papers are life cycle CO2 emission evaluation of electric vehicles, life cycle simulation of reuse among multiple product life cycles, disassembly part selection based on the idea of life expectancy, and personalization design aiming at avoiding mass production and mass disposal. The latter two papers are rather fresh in this journal. The fifth paper deals with customer preferences in Indonesia. Focusing on life styles in developing countries is a very important topic emphasized in SDGs. The last paper deals with food waste, which is emphasized in both SDGs and Circular Economy. Most of the papers, revised and extended in response to the editor’s invitations, were originally presented at EcoDesign 2017: the tenth International Symposium on Environmentally Conscious Design and Inverse Manufacturing, held in Tainan, Taiwan. The editor sincerely thanks the authors and reviewers for their devoted work in making this special issue possible. We hope that these articles will encourage further research on design and manufacturing for environmental sustainability.

Disassembly Reuse Part Selection for Recovery Rate and Cost with Lifetime Analysis

The depletion of natural resources is a critical environmental issue, and the recovery, including reuse and recycling, of end-of-life assembled products is the key to reducing the use of natural resources. However, in order to reuse or recycle an assembled product, it is essential to consider the life expectancy or material type and the weight of the parts in the product. In addition, because the assembled products comprise various parts, manual disassembly is required, which entails high costs. To recover assembled products in an environmentally friendly and economical manner, part selection for disassembly is required. A part selection method is proposed with three selection types: reuse, recycling, and disposal. First, data-set preparation is addressed. Second, the method for selecting the disassembly parts using integer programming and the ϵ constraint method is explained. Finally, numerical experiments are conducted using the proposed part selection method with a computer as a case study. Lifetime changes of the parts/product are then analyzed.