D. Dimitrov, W. van Wijck, K. Schreve and N. de Beer
The research was undertaken to characterise the three dimensional printing (3DP) process in term of the achievable dimensional and geometric accuracy.
Abstract
Purpose
The research was undertaken to characterise the three dimensional printing (3DP) process in term of the achievable dimensional and geometric accuracy.
Design/methodology/approach
New benchmark models were developed that represent characteristics needing to be investigated. The parts were fabricated in different materials. A program was written to measure the features on a numerically controlled coordinate measurement machine. Finally, a statistical analysis was done. The results are reported in terms of statistical parameters and international tolerance (IT) grades.
Findings
The paper provides general IT grades of the 3DP process for parts printed using different materials (powders).
Research limitations/implications
The research is limited to specific materials and equipment.
Practical implications
The data is very useful for designing products to be manufactured on 3DP machines applying either direct or indirect methods.
Originality/value
3DP is more and more used for rapid prototyping with great potential towards rapid manufacturing. Designers need to know the capability profile of the process they are going to use. There is a significant lack of published data on the 3DP process characteristics. This research was conducted to fill this gap and provide much needed accuracy information.
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D. Dimitrov, K. Schreve and N. de Beer
This paper surveys the current state and capabilities of three dimensional printing (3DP). A comprehensive review of 3D Printing applications is presented. The scope of the…
Abstract
Purpose
This paper surveys the current state and capabilities of three dimensional printing (3DP). A comprehensive review of 3D Printing applications is presented. The scope of the applications includes design, manufacturing, the medical field and architecture.
Design/methodology/approach
A large variety of manufacturing applications such as rapid pattern making and rapid tooling using the 3DP process directly or as core technology, as well as further implications in design and engineering analysis, medicine, and architecture are presented and evaluated.
Findings
Some research issues are also discussed. An attempt, based on the state of the art, to show weaknesses and opportunities, and to draw conclusions about the future of this important process rounds up this paper.
Research limitations/implications
The scope of this research survey is limited to evaluation and comparison of processes that may be characterised as 3D printing technologies.
Practical implications
The study is very useful as a basis for matching evaluated 3D printing machine and process capabilities to user requirements, and forms a framework on which future comparative studies can build.
Originality/value
A comprehensive overview of the capabilities of 3DP processes is presented and evaluated. It shows the application of 3D printing beyond concept modelling. The paper is valuable for researchers as well as individuals, who require adequate and relevant comparative information during decision making.
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D. Dimitrov, K. Schreve, A. Taylor and B. Vincent
The purpose of this paper is to demonstrate the use of three‐dimensional printing (3DP) process as a base technology for rapid manufacturing of components, larger than the…
Abstract
Purpose
The purpose of this paper is to demonstrate the use of three‐dimensional printing (3DP) process as a base technology for rapid manufacturing of components, larger than the machine's build volume. This extends the 3DP applications field beyond its existing domain. The paper gives process chains and design for manufacturing and assembly guidelines.
Design/methodology/approach
Several parameters influencing the process chains are identified and their interrelations investigated. Based on this study, new process chains are developed for specific functional and material requirements. The new process chains are validated with several case studies. Where applicable, the process chains are compared qualitatively with existing methods.
Findings
The results show that the new process chains are as fast as or faster than existing methods and have similar accuracy. The most significant advantage is a more geometric freedom. There is also more opportunity for checking physical models before making the final part. Some limitations to the processes are identified and given as design guidelines.
Research limitations/implications
A quantitative comparison of existing methods with the new process was not possible.
Practical implications
The study provides useful design for manufacturing guidelines.
Originality/value
This paper shows how 3DP technology, originally only conceived as a concept modeller, can be used to manufacture components that are larger than the rapid prototyping machine's build volume. It gives guidelines for designers wishing to follow a similar route.
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This article examines the effect of party composition of government on the centralization of budgeting institutions in Hungary, Poland, the Czech Republic and Bulgaria in…
Abstract
This article examines the effect of party composition of government on the centralization of budgeting institutions in Hungary, Poland, the Czech Republic and Bulgaria in 1989-1999, and assesses the impact of the centralization of budgeting institutions on the capacity of these countries to meet the fiscal deficit requirement for the European Economic and Monetary Union (EMU) membership. The article finds that centralization of budgeting institutions through delegation to a strong finance minister and/or prime minister is likely to occur in one-party governments or coalition governments composed of parties which expect to fight repeated elections together, with effective punishment mechanisms. The article finds that countries with centralized budgeting institutions are likely to be more capable of meeting the EMU deficit requirement than countries with decentralized institutions.
The purpose of this paper is to explore the sources of meaningfulness at the workplace, according to the perceptions of hospitality employees from different national cultures in…
Abstract
Purpose
The purpose of this paper is to explore the sources of meaningfulness at the workplace, according to the perceptions of hospitality employees from different national cultures in one US‐based hotel, based on Dimitrov's empirical study about the features of the humane organization.
Design/methodology/approach
This was an exploratory research that employed a single embedded case study. There were 17 employees, selected via purposeful convenience sampling. The process of data gathering involved: personal statements, interviews, complete observations, and document analysis. Data were coded using open and theoretical codes. Content and constant comparative analysis was used to link the emerging themes.
Findings
The respondents felt that sources of meaningfulness in the workplace are: work itself and pride in the product; the social environment; the self and spirituality at work; and becoming a humane organization.
Research limitations/implications
The main recommendations for future research are to: explore the meaning of work and meaningful workplace human resource development concepts in more culturally diverse organizations in different counties and economic sectors (government and non‐profit); study the national cultural differences more specifically per cultural type, utilizing systematic methodologies for cultural differentiation; and explore other study designs.
Practical implications
Organizations are advised to: create flexible schedules and WFB policies; exhibit social responsibility; and broaden the cultural horizons of their workforce.
Originality/value
The discussion in this paper will further enhance the understanding of international human resource development as it provides a focused review of the sources of meaningfulness in the workplace found in the study of one US‐based organization, populated by the international influences of a global industry in a global world.
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James Robert Wingham, Robert Turner, Joanna Shepherd and Candice Majewski
X-Ray-computed micro-tomography (micro-CT) is relatively well established in additive manufacturing as a method to determine the porosity and geometry of printed parts and, in…
Abstract
Purpose
X-Ray-computed micro-tomography (micro-CT) is relatively well established in additive manufacturing as a method to determine the porosity and geometry of printed parts and, in some cases, the presence of inclusions or contamination. This paper aims to demonstrate that micro-CT can also be used to quantitatively analyse the homogeneity of micro-composite parts, in this case created using laser sintering (LS).
Design/methodology/approach
LS specimens were manufactured in polyamide 12 with and without incorporation of a silver phosphate glass additive in different sizes. The specimens were scanned using micro-CT to characterise both their porosity and the homogeneity of dispersion of the additive throughout the volume.
Findings
This work showed that it was possible to use micro-CT to determine information related to both porosity and additive dispersion from the same scan. Analysis of the pores revealed the overall porosity of the printed parts, with linear elastic fracture mechanics used to identify any pores likely to lead to premature failure of the parts. Analysis of the additive was found to be possible above a certain size of particle, with the size distribution used to identify any agglomeration of the silver phosphate glass. The particle positions were also used to determine the complete spatial randomness of the additive as a quantitative measure of the dispersion.
Practical implications
This shows that micro-CT is an effective method of identifying both porosity and additive agglomeration within printed parts, meaning it can be used for quality control of micro-composites and to validate the homogeneity of the polymer/additive mixture prior to printing.
Originality/value
This is believed to be the first instance of micro-CT being used to identify and analyse the distribution of an additive within a laser sintered part.
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The purpose of this paper is to explore the way leadership influences an organization to become humane through its features and behaviors; as well as the organizational…
Abstract
Purpose
The purpose of this paper is to explore the way leadership influences an organization to become humane through its features and behaviors; as well as the organizational circumstances in which humane leadership can be nurtured. The first empirical case study, in the fields of Human Resource Development (HRD) and hospitality management, to explore the way employees from different national cultures (as measured by their individualistic/collectivistic values), in a US-based hotel, perceive their workplace to be a humane organization (HO), as defined by Chalofsky (2008), was the one made by Dimitrov (2009, 2010). More specifically, the example set by leadership in the studied hospitality organization is the focus of the present descriptive manuscript. The importance of HRD concepts such as the HO for the academic study and practical development of leadership in organizations is significant, through the effects leadership has on employee satisfaction and engagement at the workplace.
Design/methodology/approach
The exploratory research mentioned above used a single embedded case study with 17 participants, selected via purposeful convenience sampling, who represented management, supervisory and professional line-level employees from a culturally diverse full-service hotel in a major metropolitan area. The instrument of Singelis et al. (1995) for horizontal and vertical individualism (I) and collectivism (C), as well as the instrument of Triandis and Singelis (1998) for I and C, was applied to every respondent to determine their cultural belonging. One-on-one interviews, written reflections and documentary analysis, as well as observations of the social and physical aspects of the participants’ workplace, were conducted.
Findings
Five leadership sub-themes were observed to the general theme “Setting the Example” of the study’s findings: company values for leadership styles and employee treatment; the legacy of one charismatic leader (the previous general manager); leader–follower communication; how the workplace feels intrinsically; and how the work environment becomes negative. The study led to the formation of two new characteristics of the HO (Dimitrov, 2009), of which one could be recommended as the main focus of leadership in an HO: being cognizant and understanding of individuals as human beings, not just as employees. The traits and behaviors of some modern leadership theories such as authentic leadership, transformational leadership and charismatic leadership were combined under the concept – humane leadership.
Research limitations/implications
The research of more culturally diverse organizations in different counties, brand cultures and economic sectors, under various research methodologies, and in the context of classical and recent leadership theories, was recommended to establish further weather I and C employees’ expectations of their leadership would make a difference for the sustenance of an HO.
Practical implications
Furthermore, organizations and HRD practitioners are encouraged to invest more time, efforts and resources into leadership development programs that create such humane leadership skills and prepare quality leaders who are well-perceived and trusted by their culturally diverse workforce.
Originality/value
The importance of HRD concepts such as the HO for the academic study and practical development of leadership in organizations is significant, through the effects leadership has on employee satisfaction and engagement at the workplace. Humane leaders can be nurtured in a humane organizational culture.
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A complex human system, whose description is only possible in a fuzzy way, was put into correspondence with management in the form of fuzzy instructions, which expressed…
Abstract
A complex human system, whose description is only possible in a fuzzy way, was put into correspondence with management in the form of fuzzy instructions, which expressed unprecisely formulated actions and led to more than one way of their understanding and realization. We call such management fuzzy. The self‐organization processes in the human systems under fuzzy management are considered — building coalitions, forming a hierarchy, etc. The principle of Gause‐Arrow is presented, according to which in every human system under fuzzy management there is at least one “leader” who possesses the highest ability of generating variety of alternatives in response of fuzzy instructions. The following statement is proved: For each coalition formed under a stable fuzzy management there is a group choice rule which is socially satisfactory in the sense of Arrow.
Jean-marc Linares, Julien Chaves-Jacob, Quentin Lopez and Jean-Michel Sprauel
The mechanical characterization of selective laser melting (SLM) parts is an industrial challenge. This paper aims to propose a methodology to control the fatigue life of 17-4Ph…
Abstract
Purpose
The mechanical characterization of selective laser melting (SLM) parts is an industrial challenge. This paper aims to propose a methodology to control the fatigue life of 17-4Ph stainless steel by selecting the most relevant manufacturing parameters: i.e. laser power, laser travel speed, hatch spacing and laser defocusing.
Design/methodology/approach
A rough and refined design of experiment (DOE) is carried out to target the best combination of process parameters. A response surface model is then constructed to predict the parameter combination that optimizes the fatigue performance.
Findings
This study results show that the fatigue limit of the specimens manufactured by SLM (471.7 MPa at 107 cycles) has reached near 90% of the value found in samples machined from a bar. This demonstrates the applicability of the method proposed to optimize the SLM process and control the fatigue life of 17-4Ph stainless steel. The study results are compared with other research works and provide an increase of 18% to the fatigue limit.
Originality/value
This study showcases a DOE methodology to optimize the SLM parameters to achieve fatigue performance as great as that of solid 17-4Ph stainless steel.
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Jekaterina Rogaten and Bart Rienties
In the last five years, there has been an increased interest across the globe, and in the United Kingdom in particular, to define, conceptualise and measure learning gains. The…
Abstract
In the last five years, there has been an increased interest across the globe, and in the United Kingdom in particular, to define, conceptualise and measure learning gains. The concept of learning gains, briefly summarised as the improvement in knowledge, skills, work-readiness and personal development made by students during their time spent in higher education, has been hailed by some as an opportunity to measure ‘excellence’ in teaching. This chapter will review some of the common definitions and the methods employed in research on learning gains. Secondly, we will provide a critical evaluation of the computational aspects of learning gains (e.g., raw gain, normalised gain). Finally, we will critically reflect upon the lessons learnt and what is not yet known in terms of learning gains.