Carlos Alejandro Garcia Rosales, Hoejin Kim, Mario F. Garcia Duarte, Luis Chavez, Mariana Castañeda, Tzu-Liang Bill Tseng and Yirong Lin
Shape memory polymer (SMP) is capable of recovering its original shape from a high degree of deformation by applying an external stimulus such as thermal energy. This research…
Abstract
Purpose
Shape memory polymer (SMP) is capable of recovering its original shape from a high degree of deformation by applying an external stimulus such as thermal energy. This research presents an integration of two commercial SMP materials (DiAPLEX and Tecoflex) and a material extrusion (ME) printer to fabricate SMP parts and specimens. The material properties such as Young’s modulus of the specimens was examined as a process output. Furthermore, stress-strain curve, strain recovery, instant shape-fixity ratio, long-term shape-fixity ratio and recovery ratio of SMP specimens during a thermo-mechanical cycle were investigated.
Design/methodology/approach
The ME fabrication settings for the SMP specimens were defined by implementing a design of experiments with temperature, velocity and layer height as process variables.
Findings
It was found, according to main effect and iteration plots, that fabrication parameters have an impact on Young’s modulus and exist minimum iteration among variables. In addition, Young’s modulus variation of DiAPLEX and Tecoflex specimens was mostly caused by velocity and layer height parameters, respectively. Moreover, results showed that SMP specimens were able to recover high levels of deformation.
Originality/value
This paper is a reference for process control and for rheological properties of SMP parts produced by ME fabrication process.
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Carlos Alejandro Garcia Rosales, Hoejin Kim, Mario F. Garcia Duarte, Luis Chavez, Tzu-Liang Bill Tseng and Yirong Lin
Shape memory polymers (SMPs) are classified as smart materials owing to their inherent stimulus-induced response. SMPs are capable of recovering partially or totally to its…
Abstract
Purpose
Shape memory polymers (SMPs) are classified as smart materials owing to their inherent stimulus-induced response. SMPs are capable of recovering partially or totally to its original shape after a high degree of deformation by external stimulus. The most used stimuli are thermal, light, magnetic field and electricity. This research aims to characterize the toughness property of thermo-responsive SMP specimens fabricated by the material extrusion (ME) process and to investigate the impact of ME parameters on specimen maximum load and load-displacement curves. Moreover, to investigate the recovery efficiency based on the initial and post toughness generated by the compact tension test.
Design/methodology/approach
A design of experiments with three parameters (temperature, velocity and layer height) defined the ME settings to fabricate the specimens. The ME raster orientation factor was also evaluated separately. In addition, one more specimen group assisted by a clamp during the recovery process was compared with a specimen control group. After fabrication, specimens were submitted to a thermo-mechanical cycle that encompasses a compact tension test and a thermo-recovery process. Comparison studies of load-displacement, toughness and recovery efficiency of the specimens were carried out to determine the optimized fabrication parameters.
Findings
It was found that ME parameters and raster orientation impacted the test results. Samples with the clamp support during recovery returned a higher toughness than samples without support. Finally, results showed that the shape memory effect can contribute with up to 43 per cent recovery efficiency in a first recovery and up to 23 per cent in a second recovery of damaged specimens.
Originality/value
This paper is a reference for toughness and recovery properties of SMP parts produced by the ME fabrication process.
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Wen-Yau Liang, Chun-Che Huang, Tzu-Liang (Bill) Tseng and Jia-Chi Chen
Up to 89.1% of consumers have changed their decisions due to the influence of online reviews. In order to increase the number of reviews, some websites and platforms have adopted…
Abstract
Purpose
Up to 89.1% of consumers have changed their decisions due to the influence of online reviews. In order to increase the number of reviews, some websites and platforms have adopted feedback incentives. Research shows that offering review incentives does increase the likelihood of consumers writing reviews. However, the review reward system also brings some problems. Consumers may doubt the authenticity of product reviews that are incentivized by rewards, believing that reviewers are only writing reviews for personal gain, which has a negative impact on the credibility of the reviews. To address this issue, this study proposes a mechanism for mandatory disclosure of review incentives as research demonstrates that transparent online communication of a platform’s efforts can substantially boost review helpfulness restore trust in online platforms, and even improve purchase intentions.
Design/methodology/approach
This study applies the S-O-R (Stimulus-Organism-Response) theoretical framework and utilizes a simulated situational questionnaire to investigate the impact of online reviews on consumers' emotional and behavioral responses within the context of a mandatory disclosure review reward system. The model identifies four key constructs: review quality as the Stimulus, review credibility and review usefulness as the Organism, and purchase intention as the Response. Data were collected through the questionnaire and subsequently analyzed to understand these relationships.
Findings
The results show that review quality has a significant positive impact on review credibility, review usefulness and purchase intention. Similarly, review credibility and review usefulness also have significant positive impacts on purchase intention.
Originality/value
To mitigate the potential negative effects of review reward systems, this study introduces a mandatory disclosure of the review reward and examines its impact using a simulated situational questionnaire. The study hypothesizes that mandatory disclosure of rewarded reviews enables consumers to identify these reviews, which may, in turn, enhance their purchase intentions.
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Hoejin Kim, Yirong Lin and Tzu-Liang Bill Tseng
The usage of additive manufacturing (AM) technology in industries has reached up to 50 per cent as prototype or end-product. However, for AM products to be directly used as final…
Abstract
Purpose
The usage of additive manufacturing (AM) technology in industries has reached up to 50 per cent as prototype or end-product. However, for AM products to be directly used as final products, AM product should be produced through advanced quality control process, which has a capability to be able to prove and reach their desire repeatability, reproducibility, reliability and preciseness. Therefore, there is a need to review quality-related research in terms of AM technology and guide AM industry in the future direction of AM development.
Design/methodology/approach
This paper overviews research progress regarding the QC in AM technology. The focus of the study is on manufacturing quality issues and needs that are to be developed and optimized, and further suggests ideas and directions toward the quality improvement for future AM technology. This paper is organized as follows. Section 2 starts by conducting a comprehensive review of the literature studies on progress of quality control, issues and challenges regarding quality improvement in seven different AM techniques. Next, Section 3 provides classification of the research findings, and lastly, Section 4 discusses the challenges and future trends.
Findings
This paper presents a review on quality control in seven different techniques in AM technology and provides detailed discussions in each quality process stage. Most of the AM techniques have a trend using in-situ sensors and cameras to acquire process data for real-time monitoring and quality analysis. Procedures such as extrusion-based processes (EBP) have further advanced in data analytics and predictive algorithms-based research regarding mechanical properties and optimal printing parameters. Moreover, compared to others, the material jetting progresses technique has advanced in a system integrated with closed-feedback loop, machine vision and image processing to minimize quality issues during printing process.
Research limitations/implications
This paper is limited to reviewing of only seven techniques of AM technology, which includes photopolymer vat processes, material jetting processes, binder jetting processes, extrusion-based processes, powder bed fusion processes, directed energy deposition processes and sheet lamination processes. This paper would impact on the improvement of quality control in AM industries such as industrial, automotive, medical, aerospace and military production.
Originality/value
Additive manufacturing technology, in terms of quality control has yet to be reviewed.
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Anabel Renteria, Luisa F. Garcia, Jorge A. Diaz, Luis C. Delfin, Jaime E. Regis, Elizabeth I. Reza, David Espalin, Tzu-Liang Bill Tseng and Yirong Lin
The purpose of this study is to evaluate different 3D structures for humidity sensing that will enable the fabrication of complex geometries with high moisture sensitivity.
Abstract
Purpose
The purpose of this study is to evaluate different 3D structures for humidity sensing that will enable the fabrication of complex geometries with high moisture sensitivity.
Design/methodology/approach
Humidity sensors based on alumina ceramics were fabricated using direct ink write (DIW) technique. Different engineered surface area, polymer binder ratio and post-processing treatment were considered to increase moisture sensitivity.
Findings
It was found that the binder ratio plays an important role in controlling the rheology of the paste during printing and determining the pore size after post-processing treatment. The sensibility of the fabricated humidity sensor was investigated by measuring its capacitance response toward relative humidity (RH) varying from 40% to 90% RH at 25°C. It is shown that using 3D lattice design, printed alumina humidity sensor could improve sensitivity up to 31.6 pF/RH%, over an order of magnitude higher than solid alumina.
Originality/value
Most of the alumina humidity sensors available are films in nature because of manufacturing difficulties, which limited its potential of higher sensitivity, and thus broader applications. In this paper, a novel 3D alumina humidity sensor was fabricated using DIW 3D printing technology.
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Kym Fraser, Hans-Henrik Hvolby and Tzu-Liang (Bill) Tseng
Maintenance and its management has moved from being considered a “necessary evil” to being of strategic importance for most competitive organisations around the world. In terms of…
Abstract
Purpose
Maintenance and its management has moved from being considered a “necessary evil” to being of strategic importance for most competitive organisations around the world. In terms of the identification and use of organisational-wide maintenance management models the picture is not clears from both a literature and practical perspective. The purpose of this paper is to shed light on the various models and their use in real-world applications, and in doing so, explores the gap between academic research and practice.
Design/methodology/approach
For this paper two comprehensive reviews of the literature were undertaken, first, to identify and categorise the various maintenance management models, and second, to determine the depth of empirical evidence for the popular models in real-world applications. Descriptive analysis of both the practical examples and empirical evidence rates (EER) for maintenance related journals is provided.
Findings
Within the literature 37 maintenance management models were identified and categorised. From these, three models were found to be popular: total productive maintenance (TPM), condition based maintenance, and reliability centred maintenance. While several thousand papers discussed these three models, only 82 articles were found to provide empirical evidence.
Research limitations/implications
While providing a sound foundation for future research the outcomes are based solely on academic literature. Analysis of EER outside the field of maintenance is needed to make comparisons.
Practical implications
The paper offers practitioners a detailed contemporary overview of maintenance management models along with tabulated results of practical examples to present day organisations. Such practical-focused papers are very limited within academic literature.
Social implications
With EER as low as 1.5 per cent for some journals this paper acts as a reminder to researchers that they have an obligation to society to spend taxpayer funded research on addressing social needs and real-world problems.
Originality/value
This paper makes a concerted attempt to link academic research with management and operational practitioners. While the paper is critical of the current academic imbalance between theory and practice, a number of suggestions to improve EER are offered in the conclusions.