Michael Rosenthal, Markus Rüggeberg, Christian Gerber, Lukas Beyrich and Jeremy Faludi
The purpose of this study is to quantify the vertical shrinkage rates and the mechanical strength of three-dimensional (3D) printed parts for a variety of wood-based materials for…
Abstract
Purpose
The purpose of this study is to quantify the vertical shrinkage rates and the mechanical strength of three-dimensional (3D) printed parts for a variety of wood-based materials for liquid deposition modeling.
Design/methodology/approach
The overall hypothesis was that a well-chosen combination of binders, fibers and fillers could reduce shrinkage in the Z dimension and increase compressive and flexural strength (DIN 52185, 52186). To test this assumption, eight sub-hypotheses were formulated. Mixtures of the ingredients were chosen in different ratios to measure the performance of prints. For time efficiency, an iterative heuristic approach was used – not testing all variations of all variables in even increments, but cutting off lines of testing when mixtures were clearly performing poorly.
Findings
The results showed that some mixtures had high dimensional accuracy and strength, while others had neither, and others had one but not the other. Shrinkage of 3D printed objects was mainly caused by water release during drying. An increase of the wood as well as the cement, sand, salt and gypsum content led to reduced vertical shrinkage, which varied between 0 and 23%. Compressive and flexural strength showed mixed trends. An increase in wood and salt content worsened both strength properties. The addition of fibers improved flexural, and the addition of cement improved compression strength. The highest strength values of 14 MPa for compressive and 8 MPa for flexural strength were obtained in the test series with gypsum.
Originality/value
This paper is an important milestone in the development of environmentally friendly materials for additive manufacturing. The potential of many ingredients to improve physical properties could be demonstrated.
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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.
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Federica Murmura and Laura Bravi
In the world economy there is the emergence of advanced manufacturing technologies that are enabling more cost and resource-efficient small-scale production. Among them, additive…
Abstract
Purpose
In the world economy there is the emergence of advanced manufacturing technologies that are enabling more cost and resource-efficient small-scale production. Among them, additive manufacturing, commonly known as 3D printing, is leading companies to rethink where and how they conduct their manufacturing activities. The purpose of this paper is to focus in the Italian wood-furniture industry to understand if the companies in this sector are investing in additive manufacturing techniques, to remain competitive in their reference markets. The research also attempts to investigate the potential sustainable benefits and limitations to the implementation of 3D printing in this specific sector, considering the companies that have already implemented this technology.
Design/methodology/approach
Data were collected using a structured questionnaire survey performed on a sample of 234 Italian companies in this sector; 76 companies claimed to use 3D printing in their production system. The questionnaire was distributed via computer-assisted web interviewing and it consisted of four sections.
Findings
The research has highlighted how Italian 3D companies have a specific profile; they are companies aimed at innovating through the search for new products and product features, putting design and Made in Italy in the first place. They pay high attention to the image they communicate to the market and are highly oriented to the final customer, and to the satisfaction of its needs.
Originality/value
The study is attempting to expand a recent and unexplored research line on the possible advantages and disadvantages of the implementation of emerging production technologies such as 3D printing.