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Article
Publication date: 1 September 1995

F. Klocke, T. Celiker and Y.‐A. Song

The materials which can currently be processed using commercially available rapid prototyping techniques have limited mechanical characteristics. Describes research into two…

1617

Abstract

The materials which can currently be processed using commercially available rapid prototyping techniques have limited mechanical characteristics. Describes research into two processes which offer metal part capabilities, namely selective laser sintering and laser generating. Pays particular attention to the selection of suitable materials. Discusses the application of these techniques to the manufacture of metal tools.

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Rapid Prototyping Journal, vol. 1 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 September 1995

B. Van der Schueren and J.P. Kruth

Selective metal powder sintering is a layer‐by‐layer manufacturing system producing metallic parts with good mechanical properties. Describes why an Fe‐Cu powder mixture has been…

2730

Abstract

Selective metal powder sintering is a layer‐by‐layer manufacturing system producing metallic parts with good mechanical properties. Describes why an Fe‐Cu powder mixture has been selected as the basic material for the process. Deals with the powder deposition issue and proposes a mechanism which can deposit thin powder layers on top of a recipient. Shows that the powder deposition mainly depends on the powder properties. States that the required powder properties are partially compatible with the specifications set by the technology of selective sintering but that some properties are in conflict with one another. Discusses the resulting compromises needed in the powder mixtures and the required modifications to the deposition mechanism.

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Rapid Prototyping Journal, vol. 1 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 December 1998

V. Yevko, C.B. Park, G. Zak, T.W. Coyle and B. Benhabib

Current commercial rapid prototyping systems can be used for fabricating layered models for subsequent creation of fully‐dense metal parts using investment casting. Due to…

1362

Abstract

Current commercial rapid prototyping systems can be used for fabricating layered models for subsequent creation of fully‐dense metal parts using investment casting. Due to increased demand for shortened product development cycles however, there exists a demand to rapidly fabricate functional fully‐dense metal parts without hard tooling. A possible solution to this problem is direct layered rapid manufacturing of such parts, for example, via laser‐beam fusion of the metal powder. The rapid manufacturing process discussed herein is based on this approach. It involves selective laser‐beam scanning of a predeposited metal‐powder layer, forming fully‐dense claddings as the basic building block of individual layers. This paper specifically addresses only one of the fundamental issues of the rapid manufacturing process under investigation at the University of Toronto, namely the fabrication of single claddings. Our theoretical investigation of the influence of the process parameters on cladding’s geometrical properties employed thermal modeling and computer process simulation. Numerous experiments, involving fabrication of single claddings, were also carried out with varying process parameters. Comparisons of the process simulations and experimental results showed good agreement in terms of overall trends.

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Rapid Prototyping Journal, vol. 4 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 December 2002

Hwa‐Hsing Tang

This paper proposes a new layered manufacturing method for forming a ceramic part, ceramic laser fusing (CLF). It involves mixing ceramic powder with an inorganic…

1403

Abstract

This paper proposes a new layered manufacturing method for forming a ceramic part, ceramic laser fusing (CLF). It involves mixing ceramic powder with an inorganic temperature‐resistant binder to form a thin green body layer. Due to laser radiation, the green body layer is melted locally and the substrate, which is also formed by green body layers, underneath it is wetted by the melted phase. This process can minimize the “balling effect”. In comparison with other layered manufacturing methods, in hand of CLF the ceramic green layer is fused together directly by laser exposure, requiring no conventional sintering post process. Furthermore, during laser fusion this process is able to compensate dimensional error due to shrinkage. Therefore, CLF is suitable for producing complex part with less distortion. Despite crack sensitivity, this process may have a potential to fabricate investment mould for precision casting.

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Rapid Prototyping Journal, vol. 8 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 June 2017

Afet Çeliker

Sustainable architecture is a well-known and studied subject for severeal decades. The environmental awareness of professionals has put sustainability in the center of the…

172

Abstract

Sustainable architecture is a well-known and studied subject for severeal decades. The environmental awareness of professionals has put sustainability in the center of the profession of architecture and has resulted in introducing and implementing ecological designs both in the scale of buildings and cities. This article presents sustainable architecture criteria, reckons regional aspects, interprets vernacular architecture and, proposes sustainable housing unit models for Mediterranean region, specifically Cyprus. The article intends to study existing researches regarding the subject, reveals and updates key aspects on sustainable housing by focusing on the passive solar systems through proposals. The article contains proposals of an experimental and conceptual approach of a group of graduate studio course students who are architects and interior designers. The conceptual approaches of design proposals are sustainable through the usage of local materials, orientation, usage of passive solar systems, natural ventilation and lighting, hence these proposals are intended to create a diversity. In that sense, this article presents possibilities of ideal plan layouts and facades for sustainable architectural housing units in Mediterranean region, Cyprus, based on the revealed key aspects on sustainability. The originality of the article is on the design proposals that take inspiration from the characteristics of vernacular architecture, but show a contemporary approach of design.

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Open House International, vol. 42 no. 2
Type: Research Article
ISSN: 0168-2601

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Article
Publication date: 1 October 2002

H.C.H. Ho, W.L. Cheung and I. Gibson

A non‐contact infrared temperature sensor was used to monitor the temperature–time relation of a point on the powder bed during laser sintering. The results were translated into a…

1601

Abstract

A non‐contact infrared temperature sensor was used to monitor the temperature–time relation of a point on the powder bed during laser sintering. The results were translated into a temperature–distance relation of the monitored spot with respect to its distance from the laser beam. The effect of particle size of polycarbonate (PC) powder on the temperature–distance relation was studied. The maximum temperature attained at the monitored spot was found to increase with decreasing size of the PC particles. The phenomenon was probably caused by the higher packing density of the smaller particles, and more laser energy was absorbed near the powder bed surface. The temperature–distance relations of some common additives such as graphite, quartz, silica and talc were also studied, and graphite was found to give the highest temperature distribution. PC/graphite composite powders were blended and sintered under similar conditions. The surface temperature of the powder bed increased greatly with the addition of a small amount (up to 2 per cent) of graphite powder. The result was attributed to the higher absorptance of CO2 laser energy by the graphite powder.

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Rapid Prototyping Journal, vol. 8 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 25 October 2019

Cem Oktay Guzeller and Nuri Celiker

The purpose of this study is expected to reveal the relationship between organizational commitment and turnover intention in the tourism and hospitality literature with more…

6849

Abstract

Purpose

The purpose of this study is expected to reveal the relationship between organizational commitment and turnover intention in the tourism and hospitality literature with more generalizable results, and thus, provide researchers with a new perspective for future studies. In this context, Individual studies that examined the relationship between organizational commitment and turnover intention in the tourism and hospitality industry were systematically identified by a comprehensive literature review.

Design/methodology/approach

Individual studies were synthesized and analyzed via a meta-analysis method to reveal whether any relationship exists between organizational commitment and turnover intention and to estimate the direction and intensity of the relationship in a more reliable and comprehensive manner. The analyses were carried out on 13 scientific papers that met the inclusion criteria.

Findings

Results showed that a moderate negative relationship exists between organizational commitment and turnover intention of employees in the tourism and hospitality industry. In this context, individuals who have emotional commitments to their institutions will have lower turnover intentions than others. The right personal selection, performance evaluation techniques, promotion, training and development opportunities, career opportunities and talent management and functional virtues such as strong communication, trust and justice will not only reinforce organizational commitment but also attract talented individuals to an organization and ensure employee retention.

Originality/value

In the current study, individual studies focusing on the relationship between organizational commitment and turnover were cumulatively collected, synthesized and analyzed. By way of providing a review of individual studies, the study provides cumulative and reliable evidence to the literature regarding the relationship between organizational commitment and turnover, and hence, contributes to the further progression of the field. The study is also the first meta-analysis carried out on the subject in question.

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International Journal of Culture, Tourism and Hospitality Research, vol. 14 no. 1
Type: Research Article
ISSN: 1750-6182

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Article
Publication date: 20 March 2017

Vyacheslav Shulunov

This study aims to give a description of conformal transformation Cartesian coordinates into spiral coordinates using the example of roll powder sintering (RPS) additive…

167

Abstract

Purpose

This study aims to give a description of conformal transformation Cartesian coordinates into spiral coordinates using the example of roll powder sintering (RPS) additive manufacturing (AM) technology. RPS has several advantages over dominant AM processes currently available in the market. RPS allows accomplishing designs, which are impossible, very expensive and difficult to create by other methods. The technology requires slicing a 3D object with spiral scanning.

Design/methodology/approach

The paper describes the possibility of accurate 3D object transformation into a flat ribbon by spiral coordinate system. Parameters of conformal transformation are calculated according to the equation of equivalence between (x, y, z) and (l, z) coordinates.

Findings

As numerical examples show, it is possible to convert three-dimensional space to two-dimensional one if you know the thickness of the spatial layer. The proposed methodology can be used for the transformation of 3D computer-aided design models into 2D strip models.

Originality/value

In this paper, the author proposes a method of converting Cartesian coordinates into spiral coordinates. Conformal transformation of three-dimensional space to two-dimensional one by use of spiral coordinate system is demonstrated by RPS AM technology, which allows to produce objects with high accuracy.

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Article
Publication date: 5 June 2007

L‐E. Rännar, A. Glad and C‐G. Gustafson

The purpose of this paper is to present a comparative study, regarding cooling time and dimensional accuracy, of conventional injection mold cooling channel layouts, using…

3534

Abstract

Purpose

The purpose of this paper is to present a comparative study, regarding cooling time and dimensional accuracy, of conventional injection mold cooling channel layouts, using straight holes and a baffle, and free‐form fabricated (FFF) layout, manufactured by the direct‐metal rapid tooling (RT) method electron beam melting (EBM). Many other methods have been proven useful for RT, but the authors have not found any publications where EBM has been used to manufacture injection molding tools.

Design/methodology/approach

A test part was designed in order to replicate a common and important issue: inadequate cooling in deep cores. The part and the different cooling layouts were analyzed in an injection molding simulation software and the numerical results were compared with corresponding experimental results.

Findings

The analyses showed an improvement in both cooling time and dimensional accuracy in favor of conformal FFF cooling channels manufactured by EBM. The experimental results correlate well with the numerical tests, however with some discrepancies.

Research limitations/implications

The results presented are based on the direct‐metal RT method EBM, and they were obtained using a specific test part.

Originality/value

This paper can be a useful aid when designing mold tools and especially when considering the usage of FFF cooling channels versus conventional cooling design. It can also serve as a reference when comparing the efficiency in terms of cooling time and dimensional accuracy between different layouts.

Details

Rapid Prototyping Journal, vol. 13 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 March 2014

Afet Çeliker, Banu Tevfikler Çavuşoğlu and Zehra Öngül

Cosmology is of essence for the life of traditional man not only to live in a meaningful universe, but to bound himself with the universe to achieve well-being as well…

80

Abstract

Cosmology is of essence for the life of traditional man not only to live in a meaningful universe, but to bound himself with the universe to achieve well-being as well. Architecture is a way of creating spaces through generic forms and symbols to attain this unity of man and the universe. This article interprets the courtyard house which is a well known archetype of spiritual and celestial qualities and has symbolic generic forms through the perspective of theory and practice of feng shui which is an ancient Chinese philosophy, based on the understanding of physical configuration of geographical settings and application of its principles to the built environment. The courtyard houses represented for this article are chosen on a linear axis starting from Cyprus, passing through Syria, Iraq, Iran, Afghanistan, Pakistan, India, and ending at China. In this article, principles of feng shui are selected and formulated to create an evaluation model showing entrance-courtyard relation, building shape, water element, room arrangement, and door alignment and circulation. Based on this evaluation model, the essential aspects of well-being have been revealed through the elements of architecture. In that sense, this article presents the opportunities and possibilies of an ideal plan layout by bringing an awareness to the cosmology and feng shui to achieve well-being.

Details

Open House International, vol. 39 no. 1
Type: Research Article
ISSN: 0168-2601

Keywords

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