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Article
Publication date: 18 November 2013

Xiaohu Zheng, Dapeng Dong, Lixin Huang, Xibin Wang and Ming Chen

– The paper aims to investigate tool wear mechanism and tool geometry optimization of drilling PCB fixture hole.

Abstract

Purpose

The paper aims to investigate tool wear mechanism and tool geometry optimization of drilling PCB fixture hole.

Design/methodology/approach

An experimental study was carried out to investigate the chip formation and tool wear mechanism of drilling PCB fixture holes. Two types of drill with different types of chip-split groove were used in this study. The performances of these two types of drill bots were evaluated by tool wear and the shapes of chips.

Findings

The chips of drilling fixture holes contain aluminum chips from the cover board, copper chips from the copper foil, discontinuous glass fiber and resin from the CFRP. Feed rate and drilling speed have a great influence on the chip morphology. Abrasive wear of the drill lip is the main reason of the fixture drill bit in drilling PCB, and micro-chipping is observed on the tool nose and chisel edge. The influence of distance between the chip-split groove and drill point center on the axial force and torque is not obvious.

Research limitations/implications

In this paper, hole wall roughness and drilling temperature were not analyzed in the optimization of drilling parameters. The future research work should consider them.

Originality/value

This paper investigated the mechanism of burr formation and tool wear in drilling of PCB fixture holes. Tool geometry was optimized by adding chip-split grooves.

Details

Circuit World, vol. 39 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 5 May 2015

Lixin Huang

This paper aims to analyze their generation mechanism and factors influencing burr generation. The final goal is to use appropriate drill design and drilling process to control…

Abstract

Purpose

This paper aims to analyze their generation mechanism and factors influencing burr generation. The final goal is to use appropriate drill design and drilling process to control the generation of burrs.

Design/methodology/approach

The mechanism of burr generation was studied through finite element method (FEM) simulation and drilling experiments. High-speed photography technology and scanning electron microscope (SEM) were used in this study.

Findings

High-speed drilling burr is a printed circuit board (PCB) copper foil burr. Within a certain range, the feed speed and burr height is in positive correlation, and decrease in the feeding speed will favor the exit burr. Drill angle influences burr and chisel edge affect significantly, followed by the point angle, and helical angle has little effect. From the perspective of reducing the burr, a smaller chisel edge and smaller point angle should be chosen. Grinding chisel edge is another choice to decrease the burr but also ensures the blade strength.

Originality/value

This paper investigates the mechanism of burr generation of PCB fixture hole drilling. The process of burr generation was captured by high-speed camera. The controlling methods of burr generation were illustrated at the end.

Details

Circuit World, vol. 41 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Content available
Article
Publication date: 18 November 2013

Martin Goosey

211

Abstract

Details

Circuit World, vol. 39 no. 4
Type: Research Article
ISSN: 0305-6120

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 oxygen-permeable…

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

Keywords

Article
Publication date: 2 August 2019

Tahira M. Probst, Lixin Jiang and Sergio Andrés López Bohle

The purpose of this paper is to test competing models of the relationship between job insecurity and two forms of impression management (self- and supervisor-focused) on job…

1093

Abstract

Purpose

The purpose of this paper is to test competing models of the relationship between job insecurity and two forms of impression management (self- and supervisor-focused) on job performance. Specifically, does job insecurity lead to greater subsequent impression management; or, does preventative use of impression management subsequently lead to reductions in job insecurity? Additionally, how do these both relate to in-role performance?

Design/methodology/approach

Using two-wave survey data collected from 184 working adults in the USA and the two-step approach recommended by Cole and Maxwell (2003) and Taris and Kompier (2006), the authors tested cross-lagged relationship between job insecurity and both forms of impression management by comparing four different models: a stability model, a normal causation model (with cross-lagged paths from T1 job insecurity to T2 impression management), a reversed causation model (with cross-lagged paths from T1 impression management to T2 job insecurity) and a reciprocal causation model (with all cross-lagged paths described in the normal and reversed causation model).

Findings

Results were supportive of the reversed causation model which indicated that greater use of supervisor-focused impression management at Time 1 predicted lower levels of job insecurity at Time 2 (after controlling for prior levels of job insecurity); moreover, job insecurity at Time 1 was then significantly associated with more positive in-role behaviors at Time 2. Moreover, the test of the indirect effect between T1 impression management and T2 performance was significant.

Originality/value

These results suggest that impression management clearly plays an important role in understanding the relationship between job insecurity and job performance. However, employees appear to utilize impression management as a means of pre-emptively enhancing their job security, rather than as a tool to reactively cope with perceived job insecurity.

Details

Career Development International, vol. 25 no. 3
Type: Research Article
ISSN: 1362-0436

Keywords

Article
Publication date: 13 February 2017

Nan Hu, Zhi Chen, Jibao Gu, Shenglan Huang and Hefu Liu

This paper aims to examine the effects of task and relationship conflicts on team creativity, and the moderating role of shared leadership in inter-organizational teams. An…

6528

Abstract

Purpose

This paper aims to examine the effects of task and relationship conflicts on team creativity, and the moderating role of shared leadership in inter-organizational teams. An inter-organizational team normally comprises employees from collaborated organizations brought together to conduct an initiative, such as product development. Practitioners and researchers have witnessed the prevalence of conflict in inter-organizational teams. Despite significant scholarly investigation into the importance of conflict in creativity, a deep theoretical understanding of conflict framework remains elusive.

Design/methodology/approach

A questionnaire survey was conducted in China to collect data. Consequently, 54 teams, which comprised 54 team managers and 276 team members, were deemed useful for the study.

Findings

By testing our hypotheses on 54 inter-organizational teams, we found that relationship conflict has a negative relationship with team creativity, whereas task conflict has an inverted U-shaped (curvilinear) relationship with team creativity. Furthermore, when shared leadership is stronger, the negative relationship with team creativity is weaker for relationship conflict, whereas the inverted U-shaped relationship with team creativity is stronger for task conflict.

Research limitations/implications

The main limitation is cross-sectional, which cannot establish causality in relationships. Despite this potential weakness, the present research provides insights into conflict, leadership and inter-organizational collaboration literature.

Practical implications

The findings of this study offer some guidance on how managers can intervene in the conflict situations of inter-organizational teams.

Social implications

Managers are struggling to identify ways to effectively manage team conflict when a team of diverse individuals across organizational boundaries are brought together to solve a problem. The findings of this study offer some guidance on how managers can intervene in the conflict situations of inter-organizational teams.

Originality/value

This paper provides understandings about how relationship and task conflicts affect team creativity in inter-organizational teams.

Details

International Journal of Conflict Management, vol. 28 no. 1
Type: Research Article
ISSN: 1044-4068

Keywords

Article
Publication date: 2 August 2022

Yanhui Song, Lixin Lei, Lijuan Wu and Shiji Chen

This paper focuses on the differences in domain intellectual structure discovery between author bibliographic coupling analysis (ABCA) and author co-citation analysis (ACA…

Abstract

Purpose

This paper focuses on the differences in domain intellectual structure discovery between author bibliographic coupling analysis (ABCA) and author co-citation analysis (ACA) considering all authors. The purpose of this study is to examine whether and in what ways these two all-author network approaches yield different results.

Design/methodology/approach

The sample was collected from the database of Web of Science, including all articles published in Scientometrics and Journal of Informetrics from 2011 to 2020. First, 100 representative authors were selected from each set, and ABCA matrices and ACA matrices were constructed. Second, factor analysis was carried out on the matrices, to detect the intellectual structure of scientometrics and informetrics.

Findings

The intellectual structures identified by ABCA and ACA are similar overall, but the results differ somewhat when it comes to specific structures. The ABCA is more sensitive to some highly collaborative research teams and presents a clearer picture of current intellectual structures and trends while ACA seems to have some advantages in representing the more traditional and proven research topics in the field. The combined use of ABCA and ACA allows for a more comprehensive and specific intellectual structure of research fields.

Originality/value

This paper compares the performance of ABCA and ACA detecting the intellectual structure of the domain from the perspective of all authors, revealing the intellectual structure of scientometrics and informetrics comprehensively.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/OIR-12-2020-0540.

Details

Online Information Review, vol. 47 no. 1
Type: Research Article
ISSN: 1468-4527

Keywords

Article
Publication date: 6 November 2017

Shenglan Huang, Zhi Chen, Hefu Liu and Liying Zhou

This paper aims to examine the moderating effects of job alternatives and policy support on the relationship between job satisfaction and turnover intention.

3272

Abstract

Purpose

This paper aims to examine the moderating effects of job alternatives and policy support on the relationship between job satisfaction and turnover intention.

Design/methodology/approach

A questionnaire survey was conducted in China. The study sample consisted of employees from organizations of different sizes, ownerships and industry types. Finally, 462 valid questionnaires were obtained.

Findings

Cognitive job satisfaction has a stronger negative effect on turnover than affective job satisfaction, and both effects depend on the factors related to ease of movement. Cognitive job satisfaction is more effective when job alternative is low and policy support is high, whereas affective job satisfaction leads to lesser turnover when job alternative is high and policy support is low.

Research limitations/implications

First, the demography of the respondents may have limited the generalizability of our findings. Second, this study has the limitation common to all cross-sectional studies. Third, this study focuses on turnover intention of employees rather than actual turnover rates. Finally, although the authors have identified specific factors related to ease of movement as the moderators by drawing upon the organizational equilibrium theory and current HRM literature, there may be other moderators that can affect the relationship between job satisfaction and turnover.

Practical implications

HRM managers should apply organizational HRM to the local institutional environment, especially to the human resource policies of local governments, which vary significantly across regions in China.

Social implications

HRM managers should be very cautious to approach career development task in China, especially when they have an attitude of whatever works in mature economies will surely work in organizations in Chinese society.

Originality/value

The findings extend previous career development literature that assumes unconditional effects of job satisfaction on turnover intention. With the objective of exploring the effects of conditional factors, the current study explores the special role of job alternatives and policy support in the job satisfaction – turnover relationship in the context of China. Additionally, the findings provide support for the application of organizational equilibrium theory in the context of China.

Details

Chinese Management Studies, vol. 11 no. 4
Type: Research Article
ISSN: 1750-614X

Keywords

Article
Publication date: 26 August 2014

Lixin An and Wei Li

The purpose of this paper is to study the problem of fashion flat sketches classification and proposed an integrated approach. It aims to propose a fast, reliable method to handle…

Abstract

Purpose

The purpose of this paper is to study the problem of fashion flat sketches classification and proposed an integrated approach. It aims to propose a fast, reliable method to handle multi-class fashion flat sketches classification problems and lay the foundation for the garment style query in the next step.

Design/methodology/approach

The proposed integrated approach adopts wavelet Fourier descriptor (WFD), linear discriminant analysis (LDA) and extreme learning machine (ELM). First, the discrete wavelet and Fourier transform are adopted to extract the shape features of fashion flat sketches. Then, LDA is employed for multi-class classification to reduce dimensionality. Finally, ELM is used as the classifier.

Findings

The experimental results show that the classification accuracy of the integrated approach is obtained at about 100 percent. Contrary to the traditional approaches, efficiency and accuracy are the advantages of the present approach.

Research limitations/implications

Fashion concept is conveyed often in the form of the fashion illustration or sketch. This type of sketch is useful to imply the style and overall feel of the design. However, this sketch gives no clue about the parts or sections that make up each garment. For this reason, this paper only studies the classification of flat sketches.

Originality/value

A new shape descriptor named WFD is proposed. The WFD acquires high classification accuracy comparing with Fourier descriptor (FD) and multiscale Fourier descriptor (MFD) without dimensionality reduction and nearly the same classification accuracy comparing with FD while MFD easily causes small sample size problem with dimensionality reduction using LDA. In addition, ELM is first used as the classifier in the textiles field related to the classification problem.

Details

International Journal of Clothing Science and Technology, vol. 26 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 24 May 2023

Xu Zhang, Hao Jing, Qing Zhang, Ruijun Zhang and Lixin Liu

This paper aims to guide the implementation of noise reduction measures in hoistway and reduce the aerodynamic noise generated by elevator operation, this paper aims to propose an…

Abstract

Purpose

This paper aims to guide the implementation of noise reduction measures in hoistway and reduce the aerodynamic noise generated by elevator operation, this paper aims to propose an aerodynamic noise analysis method that can solve the flow field in hoistway.

Design/methodology/approach

A turbulence-acoustic model solving the flow field in a hoistway and a numerical wind hoistway model of the ultra-high-speed elevator were established by using large eddy simulation (LES) and Curle acoustic theory.

Findings

The characteristics of pulsating flow field and aerodynamic noise around ultra-high-speed elevator are analyzed. The asymmetric characteristics of the flow field could be observed using the turbulent kinetic energy and the instantaneous vortexes in the wind hoistway model. Vortex shedding, air flow separation and recombination around the car were the key factors for aerodynamic noise generation. The sound pressure level was approximately linear to the logarithm of car speed. The increase of car deflection angle in a certain range would reduce the peak frequency of wake noise and increase the sound pressure level (SPL) value.

Originality/value

This paper provides important guidance for researches studying the aerodynamic noise in the hoistway and the technical personnel that look for the reduction measures, which greatly improves the shortcomings in the numerical simulation of the aerodynamic noise of the hoistway.

Details

Engineering Computations, vol. 40 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

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