Jeremy Faludi, Cindy Bayley, Suraj Bhogal and Myles Iribarne
The purpose of this study is to compare the environmental impacts of two additive manufacturing machines to a traditional computer numerical control (CNC) milling machine to…
Abstract
Purpose
The purpose of this study is to compare the environmental impacts of two additive manufacturing machines to a traditional computer numerical control (CNC) milling machine to determine which method is the most sustainable.
Design/methodology/approach
A life-cycle assessment (LCA) was performed, comparing a Haas VF0 CNC mill to two methods of additive manufacturing: a Dimension 1200BST FDM and an Objet Connex 350 “inkjet”/“polyjet”. The LCA’s functional unit was the manufacturing of two specific parts in acrylonitrile butadiene styrene (ABS) plastic or similar polymer, as required by the machines. The scope was cradle to grave, including embodied impacts, transportation, energy used during manufacturing, energy used while idling and in standby, material used in final parts, waste material generated, cutting fluid for CNC, and disposal. Several scenarios were considered, all scored using the ReCiPe Endpoint H and IMPACT 2002+ methodologies.
Findings
Results showed that the sustainability of additive manufacturing vs CNC machining depends primarily on the per cent utilization of each machine. Higher utilization both reduces idling energy use and amortizes the embodied impacts of each machine. For both three-dimensional (3D) printers, electricity use is always the dominant impact, but for CNC at maximum utilization, material waste became dominant, and cutting fluid was roughly on par with electricity use. At both high and low utilization, the fused deposition modeling (FDM) machine had the lowest ecological impacts per part. The inkjet machine sometimes performed better and sometimes worse than CNC, depending on idle time/energy and on process parameters.
Research limitations/implications
The study only compared additive manufacturing in plastic, and did not include other additive manufacturing technologies, such as selective laser sintering or stereolithography. It also does not include post-processing that might bring the surface finish of FDM parts up to the quality of inkjet or CNC parts.
Practical implications
Designers and engineers seeking to minimize the environmental impacts of their prototypes should share high-utilization machines, and are advised to use FDM machines over CNC mills or polyjet machines if they provide sufficient quality of surface finish.
Originality/value
This is the first paper quantitatively comparing the environmental impacts of additive manufacturing with traditional machining. It also provides a more comprehensive measurement of environmental impacts than most studies of either milling or additive manufacturing alone – it includes not merely CO2 emissions or waste but also acidification, eutrophication, human toxicity, ecotoxicity and other impact categories. Designers, engineers and job shop managers may use the results to guide sourcing or purchasing decisions related to rapid prototyping.
Details
Keywords
K. Ann McKibbon and Liz Bayley
Evidence‐based medicine (EBM) evolved from an innovative method of teaching residents to use published literature for patient care. The missing piece to this critical appraisal…
Abstract
Evidence‐based medicine (EBM) evolved from an innovative method of teaching residents to use published literature for patient care. The missing piece to this critical appraisal approach was the skills needed to find the “best evidence” to use. Acknowledgment of this need provided many opportunities for librarians to become partners in the care process, including changes in provision of collections and services, modifications in searching skills (comprehensive vs clinical), and planning and educating undergraduates and graduates across the health disciplines. Librarians have increased their skills, made changes in practice, and become more important in educating and providing resources for practicing clinicians.
Details
Keywords
Using the backdrop of an (apparently) extended visit to the West Indies, analogies with key concerns of internal audit are drawn. An unusual and refreshing way of exploring the…
Abstract
Using the backdrop of an (apparently) extended visit to the West Indies, analogies with key concerns of internal audit are drawn. An unusual and refreshing way of exploring the main themes ‐ a discussion between Bill and Jack on tour in the islands ‐ forms the debate. Explores the concepts of control, necessary procedures, fraud and corruption, supporting systems, creativity and chaos, and building a corporate control facility.
Details
Keywords
Using the backdrop of an (apparently) extended visit to the West Indies, analogies with key concerns of internal audit are drawn. An unusual and refreshing way of exploring the…
Abstract
Using the backdrop of an (apparently) extended visit to the West Indies, analogies with key concerns of internal audit are drawn. An unusual and refreshing way of exploring the main themes ‐ a discussion between Bill and Jack on tour in the islands ‐ forms the debate. Explores the concepts of control, necessary procedures, fraud and corruption, supporting systems, creativity and chaos, and building a corporate control facility.
Details
Keywords
Laura McGinn, Nicole Stone, Roger Ingham and Andrew Bengry-Howell
Despite general recognition of the benefits of talking openly about sexuality with children, parents encounter and/or create barriers to such communication. One of the key…
Abstract
Purpose
Despite general recognition of the benefits of talking openly about sexuality with children, parents encounter and/or create barriers to such communication. One of the key barriers is a desire to protect childhood innocence. The purpose of this paper is to explore parental interpretations of childhood innocence and the influence this has on their reported practices relating to sexuality-relevant communication with young children.
Design/methodology/approach
In all, 110 UK parents and carers of children aged between four and seven years were involved in focus group discussions. The discussions were transcribed and thematic network analysis was subsequently applied to the data. Following the reading and re-reading of the transcripts for meaning, context and content, individual comments and statements were identified within the data set and grouped to generate themes.
Findings
Childhood innocence was commonly equated with non-sexuality in children and sexual ignorance. Parents displayed ambiguity around the conceptualisation of non-innocence in children. Parents desire to prolong the state of childhood innocence led them to withhold certain sexual knowledge from their children; however, the majority also desired an open relationship whereby their child could approach them for information.
Originality/value
UK parents have a strong desire to maintain the social construction of their children as inherently innocent. This discourse is affecting the way in which they communicate about sexually relevant information with their children.