Search results

1 – 10 of 13
To view the access options for this content please click here
Article

Behrokh Khoshnevis, Xiao Yuan, Behnam Zahiri, Jing Zhang and Bin Xia

This paper aims to report on the experiments with the Contour Crafting Automated Construction process using sulfur concrete as the choice of construction material.

Abstract

Purpose

This paper aims to report on the experiments with the Contour Crafting Automated Construction process using sulfur concrete as the choice of construction material.

Design/methodology/approach

Several experiments have been performed at centimeter and meter scales. A finite element analysis simulation model for the behavior of sulfur concrete-based structures has been developed. Experimental results were compared with the results of simulation.

Findings

Sulfur concrete has numerous terrestrial applications and is potentially an ideal construction material for planetary construction.

Originality/value

Experimental samples of sulfur concrete were fabricated using a novel mixer/extrusion system. The mechanism was proven to be durable and stable after more than 500 h of work.

Details

Rapid Prototyping Journal, vol. 22 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article

Babak Zareiyan and Behrokh Khoshnevis

This paper aims to investigate the extrudability (flow-ability and shape-stability) of concrete mixtures by using contour crafting (CC) as an automated construction process.

Abstract

Purpose

This paper aims to investigate the extrudability (flow-ability and shape-stability) of concrete mixtures by using contour crafting (CC) as an automated construction process.

Design/methodology/approach

Several experiments have been performed for flow-ability and shape-stability of concrete mixtures. Experimental results were compared to understand significant factors and their interactions. After developing the empirical model for flow-ability, the model was validated.

Findings

The experimental investigation of varied combination of concrete components developed a mixture within constrains of the CC nozzle and improved the quality of the extruded part.

Originality/value

Several experimental samples were fabricated using CC, and the derived empirical model was validated after more than 700 h of work.

Details

Rapid Prototyping Journal, vol. 24 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article

Behrokh Khoshnevis, Satish Bukkapatnam, Hongkyu Kwon and Jason Saito

This paper presents research about the adaptation of Contour Crafting, a novel prototyping process, for two carefully chosen uncured ceramic materials. The details of the…

Abstract

This paper presents research about the adaptation of Contour Crafting, a novel prototyping process, for two carefully chosen uncured ceramic materials. The details of the construction and operation of the fabrication machine, as well as procedures and results from our preliminary experimentation are concisely presented.

Details

Rapid Prototyping Journal, vol. 7 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article

Babak Zareiyan and Behrokh Khoshnevis

This paper aims to investigate the strength at interlayer of specimens fabricated using Contour Crafting (CC) to develop a concrete mixture for large-scale…

Abstract

Purpose

This paper aims to investigate the strength at interlayer of specimens fabricated using Contour Crafting (CC) to develop a concrete mixture for large-scale three-dimensional printing.

Design/methodology/approach

The collected data from several experiments were analyzed to understand significant factors and their interactions. After developing the empirical model, condition for maximum desirability was identified and the model was validated.

Findings

The experimental investigation of varied combination of concrete components introduced an empirical model which can predict the strength at interface. Moreover, an optimized mixture within constrains of the CC nozzle was developed and validated.

Originality/value

Several experimental samples were tested, and the derived empirical model was validated after more than 600 h of work.

Details

Rapid Prototyping Journal, vol. 24 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article

Behrokh Khoshnevis, Bahram Asiabanpour, Mehdi Mojdeh and Kurt Palmer

Selective inhibition of sintering (SIS) is a layered fabrication process which is capable of rapidly producing accurate functional parts out of polymers and metals using a…

Abstract

Selective inhibition of sintering (SIS) is a layered fabrication process which is capable of rapidly producing accurate functional parts out of polymers and metals using a relatively inexpensive machine. This article presents a brief overview of the research and development aimed at establishing the feasibility and the potential of the process.

Details

Rapid Prototyping Journal, vol. 9 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article

Payman Torabi, Matthew Petros and Behrokh Khoshnevis

The purpose of this paper is to study the implementation of a commercial piezoelectric printhead in the fabrication of high-resolution metal parts selective inhibition…

Abstract

Purpose

The purpose of this paper is to study the implementation of a commercial piezoelectric printhead in the fabrication of high-resolution metal parts selective inhibition sintering (SIS-metal). SIS is a disruptive platform additive manufacturing (AM) process capable of printing parts from polymer, metal and ceramic base materials.

Design/methodology/approach

The developed system in this paper replaces the single-nozzle solenoid valve previously used in the SIS-metal process and allows for the fabrication of high-resolution parts. A design of experiments approach is utilized to study the effects of important factors in inhibitor deposition. These factors include: composition of the inhibitor, quality of the print and the amount of fluid deposited for each layer. Based on the results of these experiments, parameters have been identified for the creation of 3D parts.

Findings

The results of this study were based on the fine tuning of parameters in the updated SIS-metal machine which culminated in the fabrication of complex metallic parts. This study serves as an entry point to important areas of research in need of careful future consideration. These areas include but are not limited to machine robustness, mechanical properties, shrinkage and surface quality.

Originality/value

SIS-metal is a novel AM process developed by the CRAFT Laboratories team at the University of Southern California with potential to compete existing metal AM processes in terms of quality, price, materials and speed. The machine developed in this study signifies an order of magnitude improvement in the resolution and quality of SIS-metal parts which are comparable to those fabricated by other AM processes.

Details

Rapid Prototyping Journal, vol. 21 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article

Hongkyu Kwon, Satish Bukkapatnam, Behrokh Khoshnevis and Jason Saito

This paper presents the experimentation and modeling efforts at the University of Southern California, Los Angeles, to study the material flow patterns in the extrusion…

Abstract

This paper presents the experimentation and modeling efforts at the University of Southern California, Los Angeles, to study the material flow patterns in the extrusion and deposition stages of the Contour Crafting (CC) process. A preliminary finite element analysis (FEA) was conducted for extrusion and deposition mechanisms of CC with ceramic materials (e.g. clay) as the fabrication material. Using the FEA simulations, certain basic understandings of the effect of extrusion orifice geometry on the performance of CC were derived. A square orifice was found to be aptly suited, both in terms of delivering excellent fusion between layers as well as creating the desired external surface profile. The experimental observations support these results.

Details

Rapid Prototyping Journal, vol. 8 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article

Zhenghao Yeh and Behrokh Khoshnevis

The purpose of this paper is to present an introduction to geometric conformity principles for examining the geometric deviation between the desired (designed) and the…

Abstract

Purpose

The purpose of this paper is to present an introduction to geometric conformity principles for examining the geometric deviation between the desired (designed) and the fabricated surfaces which may be generated by a class of surface ruling fabrication processes such as flank milling, wire electrical discharge machining (WEDM), and contour crafting (CC).

Design/methodology/approach

In general, it is computationally challenging to calculate error approximation based on points. This paper proposes methods that efficiently calculate error approximation based on curve, surface area, and volume.

Findings

This paper derives the equations for calculating the ruled surface areas and the volume of 3D slices in 3D object models. One may use the difference of surface areas or volumes to determine the extent of the global conformity of the ruled surfaces. Additionally, local conformity analysis through calculating curve deviation has been introduced to improve the reliability of the global conformity analysis.

Research limitations/implications

The research results apply only to fabrication processes that generate ruled surfaces. There are, however, numerous applications in which ruled surfaces are generated, such as WEDM, any numerical control machining which uses cylindrical or conical cutting bits, and CC.

Practical implications

The research results presented will be applicable to fabrication processes such as flank milling, WEDM, and CC.

Originality/value

All developments presented are original. Also, CC, which is a candidate process for the developments presented in the paper, has been invented and developed by the authors.

Details

Rapid Prototyping Journal, vol. 15 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article

Behrokh Khoshnevis, Mahdi Yoozbashizadeh and Yong Chen

The purpose of this paper is to investigate the fundamentals of the selective inhibition sintering (SIS) process for fabricating dense metallic parts.

Abstract

Purpose

The purpose of this paper is to investigate the fundamentals of the selective inhibition sintering (SIS) process for fabricating dense metallic parts.

Design/methodology/approach

A SIS‐Metal process based on the microscopic mechanical inhibition is developed. In the process, salt solution is printed in the selected area of each powder layer; the salt re‐crystallizes when water evaporates; salt crystals decompose and grow rapidly prior to sintering; the generated salt particles spread between metal powder particles and prevent the fusing of these particles together, hence inhibiting the sintering process in the affected regions.

Findings

The SIS‐Metal process has numerous advantages. An inhibition of sintering mechanism is established for the future development of the technology. Through chemical and visual analysis using STM the mechanism for the inhibition phenomenon has been identified.

Research limitations/implications

Only bronze powder has been used in the research. Accordingly, the inhibition chemical has been engineered for this material choice. The approach should be feasible for other metals but a proper inhibitor would need to be found for each material choice.

Practical implications

The only limitation envisioned for the process may be the removal after sintering of inhibited sections in hard‐to reach areas using physical means such as scraping or vibration. Chemical removal of such sections should be possible, however.

Originality/value

The paper illustrates a new additive manufacturing technology for metallic parts fabrication.

To view the access options for this content please click here
Article

Bahram Asiabanpour, Kurt Palmer and Behrokh Khoshnevis

Selective inhibition of sintering (SIS) is a new rapid prototyping method that builds parts in a layer‐by‐layer fabrication basis. SIS works by joining powder particles…

Abstract

Selective inhibition of sintering (SIS) is a new rapid prototyping method that builds parts in a layer‐by‐layer fabrication basis. SIS works by joining powder particles through sintering in the part's body, and by sintering inhibition of some selected powder areas. In this research, statistical tools were applied to improve some important properties of the parts fabricated by the SIS process. An investigation of surface quality and dimensional accuracy was conducted using response surface methodology and through analysis of the experimental results, the impact of the factors on them was modeled. After developing a desirability function model, process operating conditions for maximum desirability are identified. Finally, the desirability model is validated.

Details

Rapid Prototyping Journal, vol. 10 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

1 – 10 of 13