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Article
Publication date: 16 October 2018

Wenxiong Lin, Huagang Liu, Haizhou Huang, Jianhong Huang, Kaiming Ruan, Zixiong Lin, Hongchun Wu, Zhi Zhang, Jinming Chen, Jinhui Li, Yan Ge, Jie Zhong, Lixin Wu and Jie Liu

The purpose of this paper is to explore the possibility of an enhanced continuous liquid interface production (CLIP) with a porous track-etched membrane as the…

Abstract

Purpose

The purpose of this paper is to explore the possibility of an enhanced continuous liquid interface production (CLIP) with a porous track-etched membrane as the oxygen-permeable window, which is prepared by irradiating polyethylene terephthalate membranes with accelerated heavy ions.

Design/methodology/approach

Experimental approaches are carried out to characterize printing parameters of resins with different photo-initiator concentrations by a photo-polymerization matrix, to experimentally observe and theoretically fit the oxygen inhibition layer thickness during printing under conditions of pure oxygen and air, respectively, and to demonstrate the enhanced CLIP processes by using pure oxygen and air, respectively.

Findings

Owing to the high permeability of track-etched membrane, CLIP process is demonstrated with printing speed up to 800 mm/h in the condition of pure oxygen, which matches well with the theoretically predicted maximum printing speed at difference light expose. Making a trade-off between printing speed and surface quality, maximum printing speed of 470 mm/h is also obtained even using air. As the oxygen inhibition layer created by air is thinner than that by pure oxygen, maximum speed cannot be simply increased by intensifying the light exposure as the case with pure oxygen.

Originality/value

CLIP process is capable of building objects continuously instead of the traditional layer-by-layer manner, which enables tens of times improvement in printing speed. This work presents an enhanced CLIP process by first using a porous track-etched membrane to serve as the oxygen permeable window, in which a record printing speed up to 800 mm/h using pure oxygen is demonstrated. Owing to the high permeability of track-etched membrane, continuous process at a speed of 470 mm/h is also achieved even using air instead of pure oxygen, which is of significance for a compact robust high-speed 3D printer.

Details

Rapid Prototyping Journal, vol. 25 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 9 July 2020

Changyu Wang, Jinming Mei and Jiaojiao Feng

Online-to-offline (O2O) knowledge-sharing economy platforms have emerged as a new public channel for matching up knowledge providers with knowledge seekers. It can…

Abstract

Purpose

Online-to-offline (O2O) knowledge-sharing economy platforms have emerged as a new public channel for matching up knowledge providers with knowledge seekers. It can facilitate offline provision and consumption of high-quality tacit knowledge around a topic upon online search and payment (called offline knowledge service transaction). However, limited research investigated this new knowledge-sharing phenomenon in the field of knowledge management (KM). The purpose of this paper is to enrich KM literature by developing a theoretical model to explore determinants of offline knowledge service transactions via O2O knowledge-sharing economy platforms from both quality and price perspectives.

Design/methodology/approach

The model was tested with objective data crawled from Zaihang – a leading O2O knowledge-sharing economy platform in China.

Findings

The results show that, in the context of O2O knowledge-sharing economy, transactions of an offline knowledge service are positively related to its provider’s popularity, but negatively related to the price. Moreover, knowledge seekers are more likely to accept and purchase a high-priced service of a knowledge topic with a higher overall review score and supplied by a provider with lower popularity and shorter response time. However, the length of offline knowledge service has no significant association with its transactions.

Originality/value

This study contributes to KM literature through investigating a new phenomenon of tacit knowledge sharing (including provision and consumption) in the context of O2O service and the sharing economy. The results give implications for knowledge providers and platform managers to facilitate online transactions of offline knowledge services.

Details

Journal of Knowledge Management, vol. 24 no. 8
Type: Research Article
ISSN: 1367-3270

Keywords

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Article
Publication date: 1 August 2016

Zhengping Chang, Zhongqi Wang, Bo Jiang, Jinming Zhang, Feiyan Guo and Yonggang Kang

Riveting deformation is inevitable because of local relatively large material flows and typical compliant parts assembly, which affect the final product dimensional…

Abstract

Purpose

Riveting deformation is inevitable because of local relatively large material flows and typical compliant parts assembly, which affect the final product dimensional quality and fatigue durability. However, traditional approaches are concentrated on elastic assembly variation simulation and do not consider the impact of local plastic deformation. This paper aims to present a successive calculation model to study the riveting deformation where local deformation is taken into consideration.

Design/methodology/approach

Based on the material constitutive model and friction coefficient obtained by experiments, an accurate three-dimensional finite element model was built primarily using ABAQUS and was verified by experiments. A successive calculation model of predicting riveting deformation was implemented by the Python and Matlab and was solved by the ABAQUS. Finally, three configuration experiments were conducted to evaluate the effectiveness of the model.

Findings

The model predicting results, obtained from two simple coupons and a wing panel, showed that it was a good compliant with the experimental results, and the riveting sequences had a significant effect on the distribution and magnitude of deformation.

Practical implications

The proposed model of predicting the deformation from riveting process was available in the early design stages, and some efficient suggestions for controlling deformation could be obtained.

Originality/value

A new predicting model of thin-walled sheet metal parts riveting deformation was presented to help the engineers to predict and control the assembly deformation more exactly.

Details

Assembly Automation, vol. 36 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 11 October 2021

Mianran Chao, Ming Jin, Peiwei Gong, Duyi Shen and Lili Zhu

This paper aims to contrastively investigate the antioxidant behavior and tribological performance of a novel multifunctional additive (PBT) and dialkyldithiophosphate…

Abstract

Purpose

This paper aims to contrastively investigate the antioxidant behavior and tribological performance of a novel multifunctional additive (PBT) and dialkyldithiophosphate (ZDDP) in complex lithium grease (CLG).

Design/methodology/approach

PBT was successfully synthesized through esterification reaction. The antioxidant behavior of PBT and ZDDP was investigated by thermal analysis, and meanwhile, their tribological performance was evaluated by Optimol SRV-IV oscillating reciprocating friction and wear tester (SRV-IV test) and MRS-1J four-ball tester (Four-ball test). Furthermore, their anticorrosion ability was determined by copper strip corrosion test.

Findings

Four-ball tests showed that the extreme pressure property of PBT was a little inferior to that of ZDDP. Besides, all the other results demonstrated that PBT showed more superior antioxidation stability, friction-reduction and antiwear ability, as well as anticorrosion performance than ZDDP.

Originality/value

This work provides a study of hindered phenol derivative as a multifunctional additive in lubricant grease, which can contribute to the development of substitution of ZDDP.

Details

Industrial Lubrication and Tribology, vol. 73 no. 8
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 29 August 2019

Ming Yang, Zhengfeng Jia, Denghu Wei, Yunxia Wang, Xianjuan Pang, Jinming Zhen, Ran Zhang and Bo Yu

The purpose of this paper is to investigate the tribological properties of carbonized polydopamine/reduced graphene oxide (CPDA/rGO) composite coatings.

Abstract

Purpose

The purpose of this paper is to investigate the tribological properties of carbonized polydopamine/reduced graphene oxide (CPDA/rGO) composite coatings.

Design/methodology/approach

CPDA/rGO composite coatings were prepared using the spray technique and subsequent pyrolysis under argon. The transmission electron microscopy, field-emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy revealed the conversion of PDA and GO into CPDA and rGO, respectively.

Findings

The results of tribological investigations show that the CPDA/rGO composite coatings with heat treatment at 300°C possess much better friction-reduction and anti-wear properties.

Originality/value

The worn surfaces of the PDA/GO composite films after heat treatment at 300°C were much smoother than that of the copper substrate. The tribofilms containing C, N, O and Cu played an important role on reducing friction and increasing wear resistance.

Details

Industrial Lubrication and Tribology, vol. 72 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

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