Search results

1 – 8 of 8
To view the access options for this content please click here
Article
Publication date: 26 July 2021

Yi Fu, Chunze Yan, Xiao Yang, Zhufeng Liu, Peng Chen and Zhaoqing Li

The purpose of this paper is to prepare metal/polymer composite materials prepared by additive manufacturing (AM) technology.

Abstract

Purpose

The purpose of this paper is to prepare metal/polymer composite materials prepared by additive manufacturing (AM) technology.

Design/methodology/approach

The effect of sintering parameters including laser power, scanning speed and slice thickness on strength and accuracy of selective laser sintering (SLS) parts were analyzed experimentally. Then, the laser sintering mechanism of nylon-12 coated copper was discussed through analyzing the interfacial reaction of nylon-12 and copper. The SLS parts were infiltrated with epoxy resin to meet the strength requirements of injection molding.

Findings

In this study, mechanical mixed nylon-12/copper and nylon-12 coated copper composite powders were investigated and compared as SLS materials. An effective dissolution–precipitation method was proposed to prepare nylon-12 coated copper powders with better processing and mechanical properties. The bending strength and modulus of fabricated parts after infiltration with epoxy reach 65.3 MPa and 3,200 MPa, respectively.

Originality/value

The composite materials can be used in the manufacture of injection molds with a conformal cooling channel for the production of common plastics in prototype quantities, showing a broad application prospect in rapid tooling.

Details

Rapid Prototyping Journal, vol. 27 no. 7
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 1 October 2018

Yunsong Shi, Wei Zhu, Chunze Yan, Jinsong Yang and Zhidao Xia

This study aims to report the preparation, selective laser sintering (SLS) processing and properties of a new nylon elastomer powder. The effects of solvent, dissolution…

Abstract

Purpose

This study aims to report the preparation, selective laser sintering (SLS) processing and properties of a new nylon elastomer powder. The effects of solvent, dissolution temperature and time and cooling method and speed on the particle size and morphologies of the prepared nylon elastomer powder are investigated.

Design/methodology/approach

The prepared nylon elastomer power possesses the particle size of around 50 mm and is spherical in shape, indicating that this study provides the feasible dissolution-precipitation process, a distillation cooling method and a suitable solvent to prepare nylon elastomer powders.

Findings

Compared to pure nylon 12, the nylon elastomer has a lower part bed temperature and a wider sintering window for the SLS process. The wider sintering window indicates the better SLS processibility. The lower part bed temperature is beneficial to the recycling of material and the decrease in the requirement of SLS equipment.

Originality/value

The nylon elastomer in this study has a lower part bed temperature and a wider sintering window for the SLS process. The wider sintering window indicates better SLS processibility. The lower part bed temperature is beneficial to the recycling of material and the decrease in the requirement of SLS equipment.

Details

Rapid Prototyping Journal, vol. 24 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 16 January 2017

Changjun Han, Chunze Yan, Shifeng Wen, Tian Xu, Shuai Li, Jie Liu, Qingsong Wei and Yusheng Shi

Selective laser melting (SLM) is an additive manufacturing process suitable for fabricating metal porous scaffolds. The unit cell topology is a significant factor that…

Abstract

Purpose

Selective laser melting (SLM) is an additive manufacturing process suitable for fabricating metal porous scaffolds. The unit cell topology is a significant factor that determines the mechanical property of porous scaffolds. Therefore, the purpose of this paper is to evaluate the effects of unit cell topology on the compression properties of porous Cobalt–chromium (Co-Cr) scaffolds fabricated by SLM using finite element (FE) and experimental measurement methods.

Design/methodology/approach

The Co-Cr alloy porous scaffolds constructed in four different topologies, i.e. cubic close packed (CCP), face-centered cubic (FCC), body-centered cubic (BCC) and spherical hollow cubic (SHC), were designed and fabricated via SLM process. FE simulations and compression tests were performed to evaluate the effects of unit cell topology on the compression properties of SLM-processed porous scaffolds.

Findings

The Mises stress predicted by FE simulations showed that different unit cell topologies resulted in distinct stress distributions on the bearing struts of scaffolds, whereas the unit cell size directly determined the stress value. Comparisons on the stress results for four topologies showed that the FCC unit cell has the minimum stress concentration due to its inclined bearing struts and horizontal arms. Simulations and experiments both indicated that the compression modulus and strengths of FCC, BCC, SHC, CCP scaffolds with the same cell size presented in a descending order. These distinct compression behaviors were correlated with the corresponding mechanics response on bearing struts. Two failure mechanisms, cracking and collapse, were found through the results of compression tests, and the influence of topological designs on the failure was analyzed and discussed. Finally, the cell initial response of the SLM-processed Co-Cr scaffold was tested through the in vitro cell culture experiment.

Originality/value

A focus and concern on the compression properties of SLM-processed porous scaffolds was presented from a new perspective of unit cell topology. It provides some new knowledge to the structure optimization of porous scaffolds for load-bearing bone implants.

Details

Rapid Prototyping Journal, vol. 23 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 20 June 2016

Wei Zhu, Chunze Yan, Yunsong Shi, Shifeng Wen, Changjun Han, Chao Cai, Jie Liu and Yusheng Shi

Semi-crystalline polymers such as polyamide-12 can be used for selective laser sintering (SLS) to make near-fully dense plastic parts. At present, however, the types of…

Abstract

Purpose

Semi-crystalline polymers such as polyamide-12 can be used for selective laser sintering (SLS) to make near-fully dense plastic parts. At present, however, the types of semi-crystalline polymers suitable for SLS are critically limited. Therefore, the purpose of this paper is to investigate the processibility of a new kind of semi-crystalline polypropylene (PP) with low isotacticity for SLS process.

Design/methodology/approach

The SLS processibility of the PP powder, including particle size and shape, sintering window, degree of crystallinity and degradation temperature, was evaluated. Effects of the applied laser energy density on the surface micromorphology, density, tensile strength and thermal properties of SLS-built PP specimens were studied.

Findings

The results show that the PP powder has a nearly spherical shape, smooth surfaces, an appropriate average particle size of 63.6 μm, a broad sintering window of 21 oC and low crystalline degree of 30.4 per cent comparable to that of polyamide-12, a high degradation temperature of 381.8°C and low part bed temperature of 105°C, indicating a very good SLS processibility. The density and the tensile strength first increase with increasing laser energy density until they reach the maximum values of 0.831 g/cm3 and 19.9 MPa, respectively, at the laser energy density of 0.0458 J/mm2, and then decrease when the applied laser energy density continue to increase owing to the degradation of PP powders. The complex PP components have been manufactured by SLS using the optimum parameters, which are strong enough to be directly used as functional parts.

Originality/value

This paper provides a new knowledge for this field that low-isotacticity PPs exhibit good SLS processibility, therefore increasing material types and broadening the application of SLS technology.

Details

Rapid Prototyping Journal, vol. 22 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 9 March 2010

Jie Liu, Biao Zhang, Chunze Yan and Yusheng Shi

The purpose of this paper is to report a study about the rapid prototyping method of dental glass‐ceramic restoration.

Abstract

Purpose

The purpose of this paper is to report a study about the rapid prototyping method of dental glass‐ceramic restoration.

Design/methodology/approach

Dental glass‐ceramic restoration materials have excellent physical and chemical, mechanical, aesthetic and biocompatibility characteristics. However, casting methods adopted at present have complicated procedures and high costs; the forming qualities are especially difficult to control. These problems greatly restrict their clinical application and promotion. Therefore, a new forming process based on selective laser sintering (SLS) technology is proposed. First, dental glass‐ceramic is processed into fine powder through a special heat treatment process. Then, the dental restoration parts are manufactured using SLS without any moulds. In this paper, the effects of processing parameters including laser power, scan speed, scan spacing and preheating temperature on the relative density and mechanical properties of the sintered parts are studied.

Findings

The experimental results have shown that for the composite powder of epoxy resin binder E‐12 and K2O‐Al2O3‐SiO2 series of dental glass‐ceramics, when preheating temperature, layer thickness, laser power, scan speed and scan spacing are, respectively, 30∼35°C, 0.08 mm, 21 W, 1,800 mm/s and 0.10 mm/s, the relative densities of dental glass‐ceramic parts are relatively high; the mechanical properties and forming effect are excellent. The relative density and bending strength of SLS parts under the optimized processing parameters are 37.40 per cent and 2.08 MPa, respectively.

Research limitations/implications

This study only concerns the preparation and SLS of the dental glass‐ceramic powders. Further investigations are planned to be conducted on post processing, such as binder decomposition, isostatic press and high temperature sintering.

Originality/value

This study will provide a theoretical and technical basis for dental glass‐ceramic restorations of SLS.

Details

Rapid Prototyping Journal, vol. 16 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 27 June 2018

Junjie Wu, Xiang Xu, Zhihao Zhao, Minjie Wang and Jie Zhang

The purpose of this paper is to investigate the effect of selective laser sintering (SLS) method on morphology and performance of polyamide 12.

Abstract

Purpose

The purpose of this paper is to investigate the effect of selective laser sintering (SLS) method on morphology and performance of polyamide 12.

Design/methodology/approach

Crystallization behavior is critical to the properties of semi-crystalline polymers. The crystallization condition of SLS process is much different from others. The morphology of polyamide 12 produced by SLS technology was investigated using scanning electron microscopy, polarized light microscopy, differential scanning calorimetry, X-ray diffraction and wide-angle X-ray diffraction.

Findings

Too low fill laser power brought about bad fusion of powders, while too high energy input resulted in bad performance due to chain scission of macromolecules. There were three types of crystal in the raw powder material, denoted as overgrowth crystal, ring-banded spherulite and normal spherulite.

Originality/value

In this work, SLS samples with different sintering parameters, as well as compression molding sample for the purpose of comparison, were made to study the morphology and crystal structure of sintered PA12 in detail.

Details

Rapid Prototyping Journal, vol. 24 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 10 June 2014

Grazielle de Oliveira Setti, Marcelo Fernandes de Oliveira, Izaque Alves Maia, Jorge Vicente Lopes da Silva, Raluca Savu and Ednan Joanni

The purpose of this paper is to compare the results from mechanical testing with measurements of surface-dependent properties performed on polyamide parts made by…

Abstract

Purpose

The purpose of this paper is to compare the results from mechanical testing with measurements of surface-dependent properties performed on polyamide parts made by selective laser sintering (SLS) to assess a possible correlation between them.

Design/methodology/approach

Fabrication of Nylon 12 (Duraform PA®) samples using different laser power levels and their characterization by tensile testing, roughness and Raman scattering measurements.

Findings

Among the surface methods investigated, the results from Raman spectroscopy are the best ones, but methods dependent on surface analysis are not really suitable as indicators of the mechanical properties. The correlation coefficients for linear fitting obtained when the normalized results of mechanical properties are plotted against the surface properties are too low. Furthermore, the ambiguity between surface and mechanical data makes it impossible to use these surface properties for prediction purposes in the industrial environment.

Originality/value

Quantitative evaluation and correlation between mechanical properties and surface properties of SLS-made samples.

Details

Rapid Prototyping Journal, vol. 20 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 1 October 2018

Qiuping Yang, Huizhi Li, Yubo Zhai, Xiaofeng Li and Peizhi Zhang

To prepare a new type of composite for selective laser sintering 3D printing, the surface of Al2O3 nanoparticles was modified by the coupling agent…

Abstract

Purpose

To prepare a new type of composite for selective laser sintering 3D printing, the surface of Al2O3 nanoparticles was modified by the coupling agent (3-methacryloxypropyl)-trimethoxy silane (KH570) before coated with thermoplastic epoxy resin (TER).

Design/methodology/approach

Laser diffraction confirmed that the size distribution of prepared powder materials in this study ranged between 20 to 80 µm. Thermogravimetric analysis (TGA) showed that the loading of organic matter was below 5 per cent. Fourier transform infrared spectroscopy indicated that the silane coupling agent molecule bound strongly with the alumina. X-ray diffraction confirmed the prepared powder materials to be α-alumina. Through the angle of repose (AOR) test, the AOR = 18.435º was obtained, suggesting the high flowability of prepared powder materials. Scanning electron microscopy (SEM) observation demonstrated that the shape of the prepared powder materials was sphere-like grains.

Findings

Molding properties of prepared powder materials were studied on the basis of particle size distribution, particle size, sphericity, crystal structure and the reaction mode of the TER. This prepared powder materials can be well applied to the production of epoxy resin-coated Al2O3 composite parts with high precision and good mechanical performance.

Originality/value

This composite can be well applied to the production of epoxy resin-coated Al2O3 composite parts with high precision and good mechanical performance.

Details

Rapid Prototyping Journal, vol. 24 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

1 – 8 of 8