P. Regenfuss, A. Streek, L. Hartwig, S. Klötzer, Th. Brabant, M. Horn, R. Ebert and H. Exner
The purpose of the paper is the elucidation of certain mechanisms of laser material processing in general and laser micro sintering in particular. One major intention is to…
Abstract
Purpose
The purpose of the paper is the elucidation of certain mechanisms of laser material processing in general and laser micro sintering in particular. One major intention is to emphasize the synergism of the various effects of q‐switched laser pulses upon metal and ceramic powder material and to point out the non‐equilibrium character of reaction steps.
Design/methodology/approach
Recent results and observations, obtained in development of “laser micro sintering,” are surveyed and analyzed. By breaking down the overall process into relevant steps and considering their possible kinetics, an approach is made towards interpreting specific phenomena of laser micro sintering. Thermodynamics upon heating of the material as well as its photo‐electronic response to the incident radiation are considered.
Findings
The findings corroborate a model whereby short pulses of high intensity provide non‐equilibrium pressure conditions at the location of incidence, that allow for the melting of metal powder with an almost immediate expansion of a plasma and/or vapor bulb. Thereby the molten material is condensed and propelled towards the substrate. A final boiling eruption after each pulse is the reason for the morphology of the laser micro‐sintered surfaces and can prevent oxidation when the process is conducted under normal atmosphere. In sintering of ceramics, the short pulsed and intensive radiation increases the chance to excite the material even with photon energies below the bandgap value and it lowers the risk of running into a destructive avalanche.
Research limitations/implications
Owing to the stochastic character of the respective sintering event, that is initiated by each individual pulse, the gathered data are not suitable yet for the formulation of an exact quantitative function between sintering behavior and laser parameters.
Practical implications
The qualitative findings yield a good rule of thumb for the choice of parameters in laser sintering on a micrometer scale and the model is conducive for advanced interpretation of other phenomena in laser material processing besides sintering.
Originality/value
The kinetics and thermodynamics of laser sintering with q‐switched pulses are approached by a qualitative explanation. The heterogeneous and non‐equilibrium character of the processes is taken into account; this character is often neglected by researchers in the area.
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P. Regenfuss, L. Hartwig, S. Klötzer, R. Ebert, Th. Brabant, T. Petsch and H. Exner
Examples are given for the technical applicability of a novel development of selective laser sintering called “laser micro sintering”.
Abstract
Purpose
Examples are given for the technical applicability of a novel development of selective laser sintering called “laser micro sintering”.
Design/methodology/approach
Together with a specific method to produce powder layers, the controlled application of pulsed radiation for the processing of sub‐μm grained metal powders was exploited to produce micro‐tools with a heretofore unattained structural resolution.
Findings
High resolution micro bodies are displayed. Instruments could be generated which proved to fulfil their designation as grip bits for micro manipulators. The micro‐bodies can be generated detachably from or firmly fixed to the construction substrate. The material of the generated bodies withstands the traction forces when used as an injection mold for polymer casts.
Research limitations/implications
Densities and structural resolutions can still be improved especially with a newly updated version of the equipment. Laser micro sintering of materials, other than metal (e.g. ceramics), has still to be developed. The introduction of the equipment and the technique into the market is on its way.
Practical implications
Micro‐tools can be generated with an overall structural resolution of 30 μm and with all the advantages of a freedom technique.
Originality/value
The paper informs the technical community on a new novel modification of the freeform technique selective laser sintering, demonstrating the solution of some problems that have hampered the progress of metal laser into resolution ranges below 100 μm. It also supplies evidence for the technical applicability.
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Thomas Hardwig, Stefan Klötzer and Margarete Boos
This paper aims to understand the current state and challenges of deploying collaborative applications in small- and medium-sized enterprises (SMEs) in Germany.
Abstract
Purpose
This paper aims to understand the current state and challenges of deploying collaborative applications in small- and medium-sized enterprises (SMEs) in Germany.
Design/methodology/approach
A survey of 101 SMEs in Germany showed how intensively collaborative applications are used today and the positive and negative effects associated with their use. Analyses proved correlations between the use of collaborative applications, the need for cooperation within SMEs and the effects and benefits of their use.
Findings
The company representatives surveyed reported a positive balance of their pro and con experiences with collaborative applications. The use of collaborative applications closely interacts with work-related demands: the more complex the requirements of joint action, the broader the benefits and challenges are of their use. The data also revealed three gaps between demand of cooperation and use of specific applications, supporting the argument that implementation of collaborative applications is challenging for SMEs. A successful use requires major changes in work systems and culture of the company.
Research limitations/implications
The data of the survey are not representative of the population of SMEs in Germany.
Originality/value
These empirical findings contribute a unique as well as substantive view of today’s state of digitalisation of project communication and management within SMEs, specifically their deployment of collaborative software.
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Rebecca Müller and Conny H. Antoni
Virtual teams are on the rise and many companies are implementing them to compete for the most talented experts. However, the use of information and communication technology…
Abstract
Purpose
Virtual teams are on the rise and many companies are implementing them to compete for the most talented experts. However, the use of information and communication technology (ICT), on which virtual teams depend, often ends in communication chaos. Research has shown that shared mental models (SMM), which are knowledge structures on team level, enhance team communication. In teams, which use ICTs, shared mental models of ICTs (ICT SMM) seem to be important. However, few studies that investigated ICT SMM have used different measurements that restrict their generalization. The purpose of this study is to define ICT SMM as well as develop and validate an ICT SMM scale.
Design/methodology/approach
This study used a cross-sectional questionnaire in two different samples (N1 = 117 students and N2 = 165 employees).
Findings
The results of item and factor analyses indicated that ICT SMM contain at least two facets, ICT functionalities and task-specific ICT use and are distinct from teamwork, taskwork and temporal SMM. The ICT SMM scale reached good validity and reliability. On an individual level, ICT SMM were positively associated with perceived team performance and coordination and negatively with ineffective communication, workload and frustration.
Research limitations/implications
Future research using teams as sample to validate the ICT SMM scale seems to be promising.
Originality/value
To the best of authors’ knowledge, this is the first study that developed and validated a rating scale to measure SMM of ICT in different samples.
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Haihong Zhu, Linda Ke, Wenjuan Lei, Cheng Dai and Baijin Chen
The purpose of this paper is to investigate the effect of the Q‐switching parameters on the sintering behavior of laser micro sintering Cu‐based metal powder, using Q‐switched…
Abstract
Purpose
The purpose of this paper is to investigate the effect of the Q‐switching parameters on the sintering behavior of laser micro sintering Cu‐based metal powder, using Q‐switched 1064 nm Nd‐YAG laser.
Design/methodology/approach
An experimental study has been performed. Metal powder mixture with Cu and Cu‐P alloy powders has been utilized. Q‐switching duration of 15 μs∼25 μs, rate of 25 kHz∼45 kHz have been used.
Findings
The results show that as the Q‐switching rate and duration increases, the peak laser power decreases and the densification enhances. However, an optimal peak laser power exists and if the peak laser power is too low, the density of the sample is also low. The densification regime of laser micro‐sintering is not only caused by the liquid phase filling the pores, but is also caused by the Cu powder migrating and by coalescence, e.g. including initial stage and intermediate stage of the traditional furnace liquid phase sintering. However, the degree of these stages depends on the peak power and input laser energy.
Originality/value
The effect of the Q‐switching parameters on sintering behavior of laser micro sintering Cu‐based metal powder using Q‐switched 1064 nm Nd‐YAG laser has been obtained. It is found that the densification behavior is Q‐switching parameters dependent, although the average laser power is same. The densification regime of laser micro‐sintering includes initial stage and intermediate stage of the traditional furnace liquid phase sintering, but the degree is Q‐switching parameters dependent.
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Dai Cheng, Haihong Zhu and Linda Ke
This paper aimed to investigate the plasma characteristics of selective laser micro sintering Cu‐based metal powder using spectra method.
Abstract
Purpose
This paper aimed to investigate the plasma characteristics of selective laser micro sintering Cu‐based metal powder using spectra method.
Design/methodology/approach
Temporal and time integrating plasma induced during selective laser micro sintering Cu‐based metal powder with a Q‐switched pulsed YAG laser have been detected and analyzed. Boltzmann plot and Stark broadening of the spectra line are utilized to analyze the electron temperature and density, respectively. The influences of the Q‐switching rate and duration on the plasma temperature and electron density have been investigated.
Findings
The results show that the plasma temperature decreases from 9,600 to 9,000 K with the increase of the Q‐switching rate from 5 to 35 kHz if Q‐switching duration of laser is kept at a constant value. The plots of temporal temperature and electron density show that the electron density varies in a faster speed than plasma temperature and the entire expansion process takes about 700 ns‐1 μs in this experiment. Evolutional images of the plasma plume using Q‐switching rate of 5 kHz and 5 μs have been registered by the ICCD with a 10 ns exposure time, which shows that the plasma plume takes about 100 ns to get to the maximum size and 600 ns to disperse.
Originality/value
The plasma spectra of selective laser micro sintering Cu‐based metal powder have been diagnosed experimentally. The plasma characteristics of selective laser micro sintering Cu‐based metal powder have been analyzed.
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Linda Ke, Haihong Zhu, Jie Yin and Xinbing Wang
– The purpose of this paper is to report the influence of the peak laser power on laser micro sintering 4-μm nickel powder using Q-switched 1064-nm Nd:YAG laser.
Abstract
Purpose
The purpose of this paper is to report the influence of the peak laser power on laser micro sintering 4-μm nickel powder using Q-switched 1064-nm Nd:YAG laser.
Design/methodology/approach
Experimental study has been performed. Nickel powder with grain size of 4 μm has been utilized. A Q-switching duration of 20-25 μs and rate of 20-40 kHz have been used.
Findings
The peak power intensity is so high that the metal particles and molten pool are blown away, leading to laser micro sintering not being successfully proceeded. The scanning line obtained by continuous-wave (CW) laser looks like a rod owing to balling effect. Using a suitable peak power intensity, a good-shaped sintering line can be obtained because the plasma can protect the molten metal from oxidation, and improve the wettability of the system. In addition, the plasma flattening effect may also contribute to the form of the good-shaped sintering line in pulsed laser sintering regime.
Originality/value
The role of plasma induced by pulsed laser with high peak power intensity has been found during pulsed laser sintering under an ambient environment.
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Leandro Feitosa Jorge, Elaine Mosconi and Luis Antonio de Santa-Eulalia
In response to the growing need for organizations to enhance their digital capabilities and the widespread adoption of enterprise social media (ESM) in the workplace, researchers…
Abstract
Purpose
In response to the growing need for organizations to enhance their digital capabilities and the widespread adoption of enterprise social media (ESM) in the workplace, researchers have extensively studied the effects of ESM on various organizational outcomes. Nonetheless, a notable theoretical gap exists regarding the influence of ESM on the development of organizational digital maturity. This paper aims to bridge this gap by conducting a comprehensive literature review to investigate how the utilization of ESM can facilitate the transformation of organizational value-creation processes, thereby contributing to the overall enhancement of digital maturity.
Design/methodology/approach
Using the information technology (IT) value-creation framework developed by Mooney et al. (1996) and applying a template analysis methodology as outlined by King (2012), the authors conducted a systematic literature review (Okoli and Schabram, 2010), to investigate the influence of ESM on value creation within the digital business environment.
Findings
The study’s outcomes are structured around a theoretical framework that combines the contingency theory and the sociotechnical perspective to provide a comprehensive understanding of digital maturity. This paper also delves into how ESM facilitates the transformation of organizational value-creation processes, ultimately contributing to the overall progress of their digital maturity.
Research limitations/implications
This study adapts existing theoretical models to fit the context of ESM and integrates multiple perspectives to provide a comprehensive understanding of its impact. It identifies a convergence in the definition of ESM and offers insights into its various dimensions and effects on value creation. Hence, scholars can use the identified theoretical frameworks and conceptual convergence to guide future investigations into the impact of ESM on value creation, fostering theoretical development and empirical research. Practitioners can benefit from the insights to develop effective strategies for implementing ESM within their organizations, aligning with broader organizational objectives to enhance performance, streamline operations and drive structural changes. Furthermore, both scholars and practitioners can use the identified limitations of the study to identify areas for further improvement and exploration, thus contributing to the advancement of knowledge and practice in ESM and value creation. Limitations of this research include the exclusion of gray literature, a relatively small sample size of analyzed articles, and the restriction to specific databases as per systematic review guidelines, potentially overlooking valuable contributions from alternative sources.
Practical implications
This paper provides a comprehensive exploration of how ESM can support value-creation processes within organizations. It offers valuable insights to help managers incorporate ESM into their digital strategies and to understand its value-creation effects.
Originality/value
Adopting a value-creation perspective and integrating the contingency theory and the sociotechnical perspective to build a comprehensive framework, this research introduces an original approach by showcasing how ESM can facilitate shifts in value-creation processes of organizations, paving the way to contribute to the development of their digital maturity.
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Jan Patrick Deckers, Khuram Shahzad, Ludwig Cardon, Marleen Rombouts, Jozef Vleugels and Jean-Pierre Kruth
The purpose of this paper is to compare different powder metallurgy (PM) processes to produce ceramic parts through additive manufacturing (AM). This creates the potential to…
Abstract
Purpose
The purpose of this paper is to compare different powder metallurgy (PM) processes to produce ceramic parts through additive manufacturing (AM). This creates the potential to rapidly shape ceramic parts with an almost unlimited shape freedom. In this paper, alumina (Al2O3) parts are produced, as Al2O3 is currently the most commonly used ceramic material for technical applications.
Design/methodology/approach
Variants of the following PM route, with indirect selective laser sintering (indirect SLS) as the AM shaping step, are explored to produce ceramic parts: powder synthesis, indirect SLS, binder removal and furnace sintering and alternative densification steps.
Findings
Freeform-shaped Al2O3 parts with densities up to approximately 90 per cent are obtained.
Research limitations/implications
The resulting Al2O3 parts contain inter-agglomerate pores. To produce higher-quality ceramic parts through indirect SLS, these pores should be avoided or eliminated.
Originality/value
The research is innovative in many ways. First, composite powders are produced using different powder production methods, such as temperature-induced phase separation and dispersion polymerization. Second, four different binder materials are investigated: polyamide (nylon-12), polystyrene, polypropylene and a carnauba wax – low-density polyethylene combination. Further, to produce ceramic parts with increased density, the following densification techniques are investigated as additional steps of the PM process: laser remelting, isostatic pressing and infiltration.
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Swee Leong Sing, Wai Yee Yeong, Florencia Edith Wiria, Bee Yen Tay, Ziqiang Zhao, Lin Zhao, Zhiling Tian and Shoufeng Yang
This paper aims to provide a review on the process of additive manufacturing of ceramic materials, focusing on partial and full melting of ceramic powder by a high-energy laser…
Abstract
Purpose
This paper aims to provide a review on the process of additive manufacturing of ceramic materials, focusing on partial and full melting of ceramic powder by a high-energy laser beam without the use of binders.
Design/methodology/approach
Selective laser sintering or melting (SLS/SLM) techniques are first introduced, followed by analysis of results from silica (SiO2), zirconia (ZrO2) and ceramic-reinforced metal matrix composites processed by direct laser sintering and melting.
Findings
At the current state of technology, it is still a challenge to fabricate dense ceramic components directly using SLS/SLM. Critical challenges encountered during direct laser melting of ceramic will be discussed, including deposition of ceramic powder layer, interaction between laser and powder particles, dynamic melting and consolidation mechanism of the process and the presence of residual stresses in ceramics processed via SLS/SLM.
Originality/value
Despite the challenges, SLS/SLM still has the potential in fabrication of ceramics. Additional research is needed to understand and establish the optimal interaction between the laser beam and ceramic powder bed for full density part fabrication. Looking into the future, other melting-based techniques for ceramic and composites are presented, along with their potential applications.