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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: 16 August 2013

Qinglong An, Dapeng Dong, Xiaohu Zheng, Ming Chen and Xibin Wang

The objective of this study is to develop an automated tool condition monitoring scheme for PCB drilling.

Abstract

Purpose

The objective of this study is to develop an automated tool condition monitoring scheme for PCB drilling.

Design/methodology/approach

Vibration signals are used to distinguish micro drill wear stages with proper features extraction and classifier design. Then a tool condition monitoring system is built up through a back propagation neural network (BPNN).

Findings

Experimental results show that BPNN is a practical method of modeling tool wear, and with this method a tool condition monitoring system is built up using energy ratio, root mean square (RMS) and kurtosis coefficient that transformed by vibration signals.

Research limitations/implications

In the further investigation, more signal samples should be computed as monitoring features for BPNN modeling. In addition, in order to build the best monitoring model, it is necessary to evaluate the performance of the BPNN model in advance, and optimize the process.

Originality/value

The paper provides a method and a system for PCB drill wear monitoring. The method and system can achieve on‐line monitoring of PCB drill condition.

Article
Publication date: 4 March 2014

Qiulin Niu, Xiaohu Zheng, Ming Chen and Weiwei Ming

Titanium alloy has the excellent performance and been widely utilized in aeroengine and airframe manufacture. However, improving the understanding of all aspects of titanium alloy…

Abstract

Purpose

Titanium alloy has the excellent performance and been widely utilized in aeroengine and airframe manufacture. However, improving the understanding of all aspects of titanium alloy is necessary. The purpose of this paper is to investigate the tribological properties of two typical titanium alloys against tungsten carbide under dry friction.

Design/methodology/approach

Reciprocating ball-disc friction tests were carried out at room temperature in different loading without lubricant to investigate the friction properties of TA19/WC-Co and TC18/WC-Co friction pairs. The influence of the load on the friction coefficient and friction force was analyzed. The worn surfaces of TA19 and TC18 specimens were observed by the digital microscopy and scanning electron microscopy (SEM). And the wear mechanism was discussed.

Findings

The results show that the friction coefficients decreased with the increase in the normal load. However, the reduction in the friction coefficient for the TC18 alloy was less than that for the TA19 alloy. The dynamic friction forces with time were not quite coincident with the variation trend of the friction coefficients during the sliding friction. The results observed by the SEM and EDS revealed that several grooving were the main type of frictional wear causing the surfaces of the TA19 and TC18 alloys.

Originality/value

It is shown in the paper that the tribological property of TA19 alloy was better than that of TC18 when sliding against tungsten carbide under the dry friction conditions. The main types of damage to the TA19/WC-Co friction pair were the ploughing, the delamination fatigue associate with abrasive wear and some diffusive wear. The ploughing and abrasion were the main wear mechanisms for the surface of TC18 alloy.

Details

Industrial Lubrication and Tribology, vol. 66 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 10 May 2013

Xiaohu Zheng, Zhiqiang Liu, Qinglong An, Xibin Wang, Zongwei Xu and Ming Chen

The purpose of this paper is to investigate the cutting mechanism of drilling printed circuit board (PCB) and to optimize the drilling parameters for decreasing burr size and…

Abstract

Purpose

The purpose of this paper is to investigate the cutting mechanism of drilling printed circuit board (PCB) and to optimize the drilling parameters for decreasing burr size and thrust force.

Design/methodology/approach

An experimental study was carried out to investigate the effect of drilling parameters on thrust force and burr formation. The drilling process of PCB was divided by the variation of drilling force signals. Analysis of variance (ANVONA) was carried out for burr size and thrust force. Desirability function method was used in multiple response optimization, to find the best drilling parameters.

Findings

Enter burr and exit burr have different morphologies and types. The generation of enter burr is mainly caused by burr bending which can be observed in micrographs, whereas the generation of exit burr is more complicated than enter burr; both burr breakup and burr bending are observed in exit burrs. In the selected area, the optimized spindle speed and feed rate for drilling PCB is 12 krev/min and 6 mm/s, respectively.

Research limitations/implications

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

Originality/value

This paper investigates the mechanism of burr formation and thrust force in drilling PCB and then optimizes the drilling parameters to decrease the burr formation and thrust force.

Details

Circuit World, vol. 39 no. 2
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: 25 December 2023

Xiaohu Deng, Mengyao Fu, Shasha Deng, Chee-Wee Tan and Zhibin Jiang

Contemporary focus on infections and deaths in the event of pandemics may distract health institutions and medical practitioners from the psychosocial consequences of the…

Abstract

Purpose

Contemporary focus on infections and deaths in the event of pandemics may distract health institutions and medical practitioners from the psychosocial consequences of the outbreak in individuals. In light of the devastation, persistency and scarcity of pandemics, it is imperative to delve into individuals' psychological state and self-preservation instincts when confronted with the environmental danger arising from pandemic conditions and the environmental restrictions being imposed.

Design/methodology/approach

Guided by the self-preservation theory, the authors advance a research model to elucidate the moderated mediation effect of secondary traumatic stress on an individual's reactions when faced with environmental danger and restriction. The authors also consider the moderating influence of environmental restriction and media use diversity. The authors subsequently validated the research model via a survey with 2,016 respondents in China. The authors employed PLS-SEM to analyze the data and assess the hypothesized paths.

Findings

Analytical results revealed that secondary traumatic stress fully mediated the impact of environmental danger on external reliance but suppresses the mediating effects on internal reliance. The authors further confirmed that environmental restriction moderated the relationship between environmental danger and reliance. Furthermore, the authors attest to the moderating influence of media use diversity on the relationship between secondary traumatic stress and external reliance.

Originality/value

This study not only extends the theoretical lens of self-preservation to public health emergencies but also yields practical guidelines for coping with pandemics. Insights from this study can be harnessed to aid populations worldwide in coping and recovering from pandemics.

Details

Industrial Management & Data Systems, vol. 124 no. 2
Type: Research Article
ISSN: 0263-5577

Keywords

Article
Publication date: 24 August 2021

Xueyan Zhang, Xiaohu Zhou, Qiao Wang, Hui Zhang and Wei Ju

Based on social influence theory (SIT) and social capital theory, this paper aims to explore the mediating role of entrepreneurial networks between technological entrepreneurs'…

Abstract

Purpose

Based on social influence theory (SIT) and social capital theory, this paper aims to explore the mediating role of entrepreneurial networks between technological entrepreneurs' political skills and entrepreneurial performance and whether market dynamics positively moderates this relationship.

Design/methodology/approach

This study collected data from 454 technological entrepreneurs in Beijing, Shanghai, Hangzhou, Guangzhou, Zhengzhou in China and examined four hypotheses by hierarchical regression analysis and bootstrapping analysis in an empirical design.

Findings

Results reveal that technological entrepreneurs' political skills not only have a direct positive impact on entrepreneurial performance (β = 0.544, t = 12.632, p < 0.001), but also have an indirect positive impact on entrepreneurial performance through entrepreneurial networks (β = 0.473, t = 10.636, p < 0.001). Entrepreneurial networks play a mediating role between entrepreneurs' political skills and entrepreneurial performance with 95% bias-corrected confidence intervals [0.034, 0.015]. Market dynamics plays a moderating role in the relationship among technological entrepreneurs' political skills, entrepreneurial networks and entrepreneurial performance (entrepreneurial performance: β = 0.190, t = 4.275, p < 0.001; entrepreneurial networks: β = 0.135, t = 4.455, p < 0.001). When market dynamics is high, technological entrepreneurs' political skills have a significant positive effect on entrepreneurial networks (simple slope = 0.309, t = 7.656, p < 0.001); but when market dynamics is low, there is no significant correlation between political skills and entrepreneurial networks (simple slope = 0.039, t = 0.966, p > 0.05).

Research limitations/implications

The study relies on self-reported data from single informants. Although the severity of common method bias is tested through two methods, future research designs should avoid the influence of common method bias. Future research should adopt a vertical tracking design, collect data from multiple sources and use subjective assessment and objective indicators to measure variables. In addition, the applicability of the results outside China is worth further empirical exploration. Therefore, the authors hope that future studies can replicate the research to different countries, different cultural backgrounds and different organizational sections to explore the generalizability of the results.

Practical implications

The findings provide useful suggestions for entrepreneurs, who can use political skills to build a strong entrepreneurial network to improve their entrepreneurial performance. The results also suggest that entrepreneurs should pay more attention to cultivating and developing their political skills through methods such as training and practice. In addition, the conclusion is of great implications to enrich the content of entrepreneurship education and guide entrepreneurship practice.

Originality/value

These findings enrich SIT and social capital theory by providing the empirical evidence of the effect of entrepreneurs' political skills on entrepreneurial performance through entrepreneurial network. They also provide deeper insights into market dynamics research by uncovering the moderating role of market dynamics in the relationship between entrepreneurs' political skills, entrepreneurial networks and entrepreneurial performance.

Article
Publication date: 31 May 2024

Chen Lin, Xiaohu Zhou and De'en Hou

The process of fostering and enhancing employee creativity (EC) is multifaceted and involves various challenges and contradictions, with paradoxical leadership (PL) playing a…

Abstract

Purpose

The process of fostering and enhancing employee creativity (EC) is multifaceted and involves various challenges and contradictions, with paradoxical leadership (PL) playing a crucial role. However, previous research has neglected the importance of employee emotions, resulting in an incomplete understanding of the underlying mechanisms. To address this gap, this study draws upon the triadic reciprocal determinism of social cognitive theory to construct a moderated mediation model. The objective is to investigate the mediating role of harmonious work passion (HP) in the relationship between PL and EC. Furthermore, the study aims to explore the moderating effect of proactive personality (PP).

Design/methodology/approach

Two surveys were carried out in eight enterprises situated in China. A total of 337 employees took part in the questionnaire survey to explore the correlation between PL, PP and HP. Additionally, 42 supervisors participated in evaluating the creativity of their subordinates. To test the proposed hypotheses, this study utilized hierarchical regression analysis on a sample of supervisor-subordinate pairs.

Findings

Paradoxical leadership is positively correlated with employee harmonious work passion. Harmonious work passion is positively correlated with employee creativity. Harmonious work passion plays a mediating role between paradoxical leadership and employee creativity. Proactive personality moderates the relationship between paradoxical leadership and harmonious work passion. Proactive personality moderates the indirect effect of harmonious work passion on the relationship between paradoxical leadership and employee creativity.

Practical implications

The results of this study provide practical suggestions for improving EC. For example, organizations can select supervisors who exhibit PL qualities and enhance the training programs for leaders in the domain of paradoxical thinking. Furthermore, it is crucial for leaders to prioritize the development of employees' HP and to be attentive to the distinct individual variations present within their workforce.

Originality/value

This study enriches the research on the mediating and moderating mechanism between PL and EC and opens the black box from the perspective of emotion. Moreover, this research examines the boundary condition under which PL functions. The study reveals the interaction of environment, personality, cognition and emotion on creativity and provides a new perspective and empirical support for future research.

Details

Leadership & Organization Development Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0143-7739

Keywords

Article
Publication date: 13 February 2023

Xueyan Zhang, Xiaohu Zhou, Qiao Wang, Zhouyue Wu and Yue Sui

Based on social influence theory, this paper aims to explore the influence of academic entrepreneurs on team innovation activities. The innovation behavior of academic team…

Abstract

Purpose

Based on social influence theory, this paper aims to explore the influence of academic entrepreneurs on team innovation activities. The innovation behavior of academic team members is the key behavior in academic entrepreneurial activities. As a special entrepreneurial group, academic entrepreneurs' political skills play an important role in stimulating team innovative behaviors.

Design/methodology/approach

This paper adopts a multi-level study design and takes as samples the paired data of 91 academic entrepreneurial teams (n = 475). Based on team cognition, it constructs a model of the influence mechanism of academic entrepreneurs' political skills on team innovation behavior and explores the mechanism of transactive memory system in this influence effect. The authors use HLM and PROCESS macro to test our multilevel model.

Findings

The results show that academic entrepreneurs' political skills positively impact team innovation behavior, and a transactive memory system plays a mediating role between them. Team psychological safety significantly enhances the positive relationship of both academic entrepreneurs' political skills and a transactive memory system with team innovation behavior. Moreover, with enhanced perceptions of team psychological safety, academic entrepreneurs' political skills are more likely to improve team innovation behavior through the transactive memory system.

Originality/value

The study explores the influence of transactive memory system on the relationship between academic entrepreneurs' political skills and team innovation behavior, with the team cognitive perspective derived from social influence theory. This provides authors with new insights on the complex dynamics at place in the team innovation process and offers implications for how we can fruitfully manage this process.

Details

European Journal of Innovation Management, vol. 27 no. 5
Type: Research Article
ISSN: 1460-1060

Keywords

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