bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructural investigation of lead‐free BGAs soldered with tin‐lead solder
Authors: Grossmann Günter , Tharian Joy , Jud Pascal , Sennhauser Urs 
Published: May 2005

PurposeThe goal of this work is to evaluate the feasibility of soldering tin‐silver‐copper balled BGAs using tin‐lead‐based solder and to investigate the influence of different production parameters on the microstructure of the solder joint.Design/methodology/approachThe soldering of the BGAs was done with various temperature profiles and two conveyor speeds under a nitrogen atmosphere in a full convection oven. One specimen from each temperature/time combination was cross‐sectioned. The cross sections were analysed with optical microscopy, scanning electron microscopy with energy dispersive X‐ray spectroscopy (SEM/EDS) at 30 kV and focused ion beam microscopy (FIB).FindingsThe cross sections show a metallurgical bond between the solder and the tin‐silver‐copper balls of the BGA, even at a peak reflow temperature of 210°C. However, the balls alloy only partially with the solder, as the liquidus of tin‐silver‐copper balls is 217°C. As soon as the peak temperature exceeds the liquidus of the ball, the solder is totally dissolved in the material of the ball. A reflow profile with a peak temperature of about 230°C on the BGA gives a homogenous reaction of the solder with the ball with a minimum formation of voids.Research limitations/implicationsThe dependence of varying reflow parameters on reliability requires detailed study. Especially the effect of a partially melted ball on the degradation of the solder joint needs to be investigated.Originality/valueFrom the findings, it can be said that soldering lead‐free balls with tin‐lead solder is possible. This is useful during the transitional period that the industry is in at the moment. More and more component manufacturers are changing their components to lead‐free, often without notice to the customer. If a production line is still running a tin‐lead process it is essential to know how to process these components with tin‐lead solder.
A systematic procedure for the selection of a lead‐free solder paste in an electronics manufacturing environment
Authors: Wable Girish S. , Chu Quyen , Damodaran Purushothaman , Srihari Krishnaswami 
Published: May 2005

PurposeHistorically, tin‐lead solder has been a commonly used joining material in electronics manufacturing. Environmental and health concerns, due to the leaching of lead from landfills into ground water, have necessitated legislation that restricts the use of lead in electronics. The transition from tin‐lead solder to a lead‐free solder composition is imminent. Several alternative solder alloys (and their fluxes) have been researched for electronics assembly in the last few years. The objective of this research was to develop a systematic selection process for choosing a “preferred” lead‐free solder paste, based on its print and reflow performance.Design/methodology/approachAfter a detailed study of industry preferences, published experimental data, and recommendations of various industrial consortia, a near eutectic tin‐silver‐copper (SAC) composition was selected as the preferred alloy for evaluation. Commercially available SAC solder pastes with a no‐clean chemistry were extensively investigated in a simulated manufacturing environment. A total of nine SAC pastes from seven manufacturers were evaluated in this investigation. A eutectic Sn/Pb solder paste was used as a baseline for comparison. While selecting the best lead‐free paste, it was noted that the selected paste has to perform as good as, if not better than, the current tin‐lead paste configuration used in electronics manufacturing for a particular application. The quality of the solder pastes was characterized by a series of analytical and assembly process tests consisting of, but not limited to, a printability test, a solder ball test, a slump test, and post reflow characteristics such as the tendency to form voids, self‐centring and wetting ability.FindingsEach paste was evaluated for desirable and undesirable properties. The pastes were then scored relative to each other in each individual test. An aggregate of individual test scores determined the best paste.Originality/valueThis paper summarizes a systematic approach adopted to evaluate lead‐free solder pastes for extreme reflow profiles expected to be observed in reflow soldering lead‐free boards.
The effect of curing on the performance of ACF bonded chip‐on‐flex assemblies after thermal ageing
Authors: Rizvi M.J. , Chan Y.C. , Bailey C. , Lu H. , Sharif A. 
Published: May 2005

PurposeAnisotropic conductive film (ACF) is now an attractive technology for direct mounting of chips onto the substrate as an alternative to lead‐free solders. However, despite its various advantages over other technologies, it also has many unresolved reliability issues. For instance, the performance of ACF assembly in high temperature applications is questionable. The purpose of this paper is to study the effect of bonding temperatures on the curing of ACFs, and their mechanical and electrical performance after high temperature ageing.Design/methodology/approachIn the work presented in this paper, the curing degree of an ACF at different bonding temperatures was measured using a differential scanning calorimeter. The adhesion strength and the contact resistance of ACF bonded chip‐on‐flex assembly were measured before and after thermal ageing and the results were correlated with the curing degree of ACF. The ACF was an epoxy‐based adhesive in which Au‐Ni coated polymer particles were randomly dispersed.FindingsThe results showed that higher bonding temperatures had resulted in better ACF curing and stronger adhesion. After ageing, the adhesion strength increased for the samples bonded at lower temperatures and decreased for the samples bonded at higher temperatures. ACF assemblies with higher degrees of curing showed smaller increases in contact resistance after ageing. Conduction gaps at the bump‐particle and/or particle‐pad interfaces were found with the help of scanning electron microscopy and are thought to be the root cause of the increase in contact resistance.Originality/valueThe present study focuses on the effect of bonding temperatures on the curing of ACFs, and their adhesion strength and electrical performances after high temperature ageing. The results of this study may help the development of ACFs with higher heat resistance, so that ACFs can be considered as an alternative to lead‐free solders.
New measurement technologies for textiles and clothing
Authors: Stylios George K. 
Published: May 2005

PurposeTo establish new measurement technologies in textiles and clothing.Design/methodology/approachThree areas are covered, diverse in methodology and approach: measurement of fabric mechanics, measurement of seam quality, and measurement of human size and shape.FindingsThree new measurement technologies have been established.Research limitations/implicationsThe mechanics are limited to the measurement of lightweight fabrics. The human measurement needs clear photographs.Practical implicationsAll techniques can make measurement more accurate and efficient in all three areas.Originality/valueAll techniques are original and have a major contribution to textile and clothing science and technology.
The advance engineering methods to plan the behaviour of fused panel
Authors: Jevšnik Simona , Geršak Jelka , Gubenšek Ivan 
Published: May 2005

PurposeThe purpose of this paper is to analyse some mechanical properties and parameters of drapability using different methods from two different points of research area: knowledge bases and numerical modelling using the finite element method.Design/methodology/approachThe approach consists of analysing some mechanical properties and parameters of drapability using different methods from two different points of research area: knowledge bases and numerical modelling using the finite element method. The knowledge bases, named FP_B‐1 and FPO_B‐2, were used to analyse the bending rigidity of fused panels. The numerical model of fused panel NMFP is used to analyse parameters of drapability.FindingsBased on the analyses of bending rigidity and draping of fused panels the conclusions indicate the significance of interaction between mechanical properties and parameters of drapability of the fused panel to garment appearance. Furthermore, the methods used present a computer approach to the study of the fused panel properties important for the computer‐based engineering and the presentation of real behaviour of all aspects of clothes.Practical implicationsThis numerical model of a fused panel enables a 3D observation of this aspect of clothes' which is a behaviour, very important contribution to the computer planning of the behaviour of produced clothes.Originality/valueA better understanding of how to construct fused panels in clothing.
A study of the relaxation phenomena in the fabrics containing elastane yarns
Authors: Geršak Jelka , Šajn Dunja , Bukošek Vili 
Published: May 2005

PurposeIn this paper, special attention is focused on the study of the relaxation phenomena of fabrics containing elastane yarn.Design/methodology/approachFor this purpose, the relaxation phenomena of wound fabric under constant deformation, as the consequence of accumulated stress during winding, were analysed. Maxwell's model and the modified standard linear solid model are used for explaining the relaxation.FindingsThe results of the study of the relaxation phenomena of fabrics containing elastane yarn show a close connection between stress relaxation under constant deformation in the fabric roll and the degree of deformation with manual unwinding. Expert knowledge of the relaxation phenomena in fabrics containing elastane yarns has a big influence on explaining the problem of dimensional changes and instability in such fabrics.Originality/valueA better understanding of the relaxation phenomena in fabrics containing elastane yarns.
Numerical optimisation of mechanical reinforcements of weak spots in textiles and garment
Authors: Šomođi Željko , Hursa Anica , Rogale Dubravko 
Published: May 2005

PurposeThe purpose of this paper is to investigate and illustrate the possibilities of a systematic engineering approach in the design of mechanical reinforcements in garments. A mechanical reinforcement can be designed using optimisation strategies.Design/methodology/approachIn this work, an iterative algorithm for minimum search based on parabolic approximations is proposed and applied in the optimisation of mechanical reinforcement in a selected model problem of a buttonhole type.FindingsOptimisation algorithm based on parabolic approximations, in conjunction with the finite element analysis, offers some promising possibilities as support for the decision‐making process in the design of mechanical reinforcements. The selection of optimisation criteria – influence parameters and corresponding weight factors – remains of course to be studied and implemented by the clothing engineering experts.Research limitations/implicationsThe intention in future work should be to optimise two or more geometric parameters simultaneously (multidimensional optimisation), and to produce a computer program for an automated optimum search.Practical implicationsThe contents of the paper could be useful for the experts in clothing engineering in the process of design or selection of the reinforcements of weak spots in textiles and garments.Originality/valueThis paper provides optimisation routes to the weak sports of mechanical reinforcements in textiles and garments.
Analysis of 3D woven structure as a device for improving thermal comfort of ballistic vests
Authors: Kunz Eva , Chen Xiaogang 
Published: May 2005

PurposeThis study presents the design, manufacture and evaluation of a type of 3D hollow woven structure, as a mean for improving ventilation underneath ballistic body armour and thus, thermal comfort.Design/methodology/approachBy means of a computational fluid dynamic package, fluid flows through different cross‐sectional tubular geometries were simulated in order to predict, which structural parameters of the 3D hollow fabrics are optimal to support ventilation.FindingsAs the result of the computational analysis four optimised 3D hollow woven structures were selected and generated on a standard weaving loom.Originality/valueInvestigation of thermal comfort of 3D ballistic vests.
Fabric design considering the optimisation of seam slippage
Authors: Lopes Miguel Rui Alberto , Mendes Lucas José , de Lurdes Carvalho Maria , Manich Albert Maria 
Published: May 2005

PurposeThe dependence of seam slippage values on fabric construction parameters makes this property an interesting case for study.Design/methodology/approachIn this study, made on a significant wool and blended fabrics sample, the seam slippage was measured, either in warp direction (weft yarns slip), or in weft direction (warp yarns slip), using a specially equipped load‐elongation tester. Testing was done following the TM 117 Woolmark Company test method.FindingsFor most fabrics, the conventional variables that impact seam slippage most seriously are opacity, polyamide content, finish type and cover factor.Research limitations/implicationsSince this research does not deal with the variable of yarn crimp in fabrics, it is the cover factor that plays the central role, as the property determining seam slippage. The yarns with lower cover factor (less crimped) are in less danger of slipping between the perpendicular yarns (more crimped) and vice versa.Practical implicationsBased on the equations given, and changing the most relevant variables concerning the explanation of the fabric seam slippage property, the fabric properties can be optimised for specific end‐uses.Originality/valueOptimisation of seam slippage in fabric design.
An experimental simulation of human body behaviour during sweat production measured at textile electrodes
Authors: Priniotakis Georgios , Westbroek Philippe , Van Langenhove Lieva , Kiekens Paul 
Published: May 2005

PurposeIn this paper an electrochemical cell is developed to test and follow up the quality of electrodes made of knitted, woven and non‐woven conductive textile material.Design/methodology/approachThis cell is constructed of two electrodes planarly positioned against each other using the support of a PVC tube and two PVC plates. Between the electrodes and the electrolyte special membranes are placed that simulate the human skin.FindingsThis research is a preliminary start of a study to investigate and understand the behaviour of textile electrodes and to gain insight in the inter‐phases electrode‐electrolyte and electrode‐skin‐electrolyte in order to be able to model the system and to use it for detection of parameters and body conditions.Research limitations/implicationsAs pointed out earlier, a lot of work still needs to be done but the preliminary work shows that promising possibilities can be offered.Originality/valueSimulation of human body behaviour during sweat production measured by textile electrodes.
QUIS 9 symposium – service excellence in management
Authors: Gustafsson Anders 
Published: May 2005

PurposeTo introduce the special issue focusing on the QUIS 9 symposium.Design/methodology/approachA brief perspective of the best papers presented at the Quality in Services (QUIS9) symposium held at Karlstad university, Sweden in June 2004.FindingsOutlines some of the highlights surrounding the conference.Originality/valueProvides a brief report of the context of the conference.
Managing overall service quality in customer care centers
Authors: Kantsperger Roland , Kunz Werner H. 
Published: May 2005

PurposeThis paper aims to clarify the interdependencies among three main stakeholder groups and to show how to manage overall service quality in customer care centers.Design/methodology/approachA framework of the relations among the target groups of a customer care center was developed. A survey methodology with a 360° approach that encompasses top management, employees and final customers as three main target groups was conducted. The sample incorporates 58 customer care centers and seven industries in Germany and Austria. Besides the management interviews, we received 1,580 completed questionnaires by employees, and 2,010 completed questionnaires by customers. Multiple regression analysis was applied on multi‐item measurement scales of the three different levels.FindingsWe were able to show that employee satisfaction is the main factor for driving customer orientation. Further management efforts resulting in employee orientation will facilitate the job of employees and increase employee loyalty.Research limitations/implicationsOnly 16 customer care centers participated in all three parts of the study.Practical implicationsCompanies should consider the needs of their employees and possibly initiate measures to foster employee satisfaction. A strict quality orientation could signal a low level of trust toward the employees. It is essential that firms invest in their employees and apply an employee‐oriented management style.Originality/valueThe study encompasses three relevant stakeholder groups on a broad empirical base, which is unique until now in the research field of customer care centers. Interdependencies among the three perspectives could be revealed.
Dynamics of service attributes: a test of Kano's theory of attractive quality
Authors: Nilsson‐Witell Lars , Fundin Anders 
Published: May 2005

PurposeThe aim of the paper is to contribute to a better understanding of the theory of attractive quality through an empirical investigation of an e‐service. Our focus is on the consistency of different levels of service attributes and their dynamics. Our empirical investigation aims to increase both the validity of the theory of attractive quality and the use of technology readiness as a means to understand the variation of customer perceptions of service attributes.Design/methodology/approachA survey of customers' technology readiness, usage and perceptions of an e‐service was conducted. Four propositions concerning the consistency and dynamics of Kano's theory of attractive quality are tested, mainly using general linear models.FindingsOur results show that by investigating customers at different stages of the service adoption curve, a better understanding of certain dynamics of service attributes can be achieved. When the e‐service was introduced, it was perceived as indifferent; at present it is seen as an attractive service by the market. But the early adopters of e‐services already regard it as a one‐dimensional or a must‐be service.Originality/valueThe study provides a new framework and methodology for how to investigate the dynamics of service attributes, not only between individuals within different market segments, but also at different service attribute levels. From a managerial standpoint, our results suggest consequential insight about the life cycle of the services that an organization provides to its customers.
Communication as an element of service value
Authors: Heinonen Kristina , Strandvik Tore 
Published: May 2005

PurposeThe paper explores consumers' responsiveness to marketing communication about various services and products in three different media. Communication value is seen as an element of service value and is measured as consumer responsiveness to marketing communication.Design/methodology/approachThe empirical data is based on interviews with consumers concerning their perceptions of the relevance and acceptance of marketing communication of 15 different services/products in three media, traditional direct mail, e‐mail and SMS. The consumers have responded to scenarios of marketing communication.FindingsFindings showed differences in consumer responsiveness to different services and physical products. The overall responsiveness was relatively low for the offerings in all media. A division into responsiveness groups demonstrates that there are also consumers that are positive to communication. The share of positive consumers varies considerably over offerings.Research limitations/implicationsThe present study did not account for some important aspects in marketing communication. Firstly, the communication was not considered as part of a firm's integrated marketing communication. The creative element was omitted even if it in practice is important in planned marketing communication. Moreover, the respondents have evaluated scenarios based on their general attitudes toward the communication. The consumer's relationship to the company/brand/offering was excluded. However, despite these limitations it shows that it is necessary to consider that products and services may have different responsiveness patterns.Practical implicationsThe emergence of digital media has increased the number of ways to interact with consumers. The variation in the responsiveness to products and services for different media indicates that it is important to have an understanding of how the media adds and subtracts value. The analysis points to the need for companies to measure the responsiveness of consumers in order to understand and enhance consumer perceived value of the communication as a part of the service.Originality/valueThe paper contributes to service marketing research by introducing the communication value and responsiveness conceptualisations that have an interest both for academic research and practitioners. This includes a new perspective on the role of communication on one hand and on the empirical findings of differences in digital interactive media on the other hand.
Flow impingement onto a flat plate with limited heated area in relation to laser gas assisted processing
Authors: Shuja S.Z. , Yilbas B.S. , Budair M.O. 
Published: May 2005

PurposeTo investigate the influence of conical and annular nozzle geometric configurations on the flow structure and heat transfer characteristics near the stagnation point of a flat plate with limited heated area.Design/methodology/approachThe conical and annular conical nozzles were designed such that the exit area of both nozzles is the same and the mass flow rate passing through the nozzles is kept constant for both nozzles. The governing equations of flow and heat transfer are modeled numerically using a control volume approach. The grid independent solutions are secured and the predictions of flow and heat transfer characteristics are compared with the simple pipe flow with the same area and mass flow rate. The Reynolds stress turbulence model is employed to account for the turbulence. A flat plate with a limited heated area is accommodated to resemble the laser heating situations and air is used as assisting gas.FindingsIt is found that nozzle exiting velocity profiles differ considerably with changing the nozzle cone angle. Increasing nozzle cone angle enhances the radial flow and extends the stagnation zone away from the plate surface. The impinging jet with a fully developed velocity profile results in enhanced radial acceleration of the flow. Moreover, the flow structure changes considerably for annular conical and conical nozzles. The nozzle exiting velocity profile results in improved heat transfer coefficient at the flat plate surface. However, the achievement of fully developed pipe flow like velocity profile emanating from a nozzle is almost impossible for practical laser applications. Therefore, use of annular conical nozzles facilitates the high cooling rates from the surface during laser heating processResearch limitations/implicationsThe results are limited with theoretical predictions due to the difficulties arising in experimental studies.Practical implicationsThe results can be used in laser machining applications to improve the end product quality. It also enables selection of the appropriate nozzle geometry for a particular machining application.Originality/valueThis paper provides information on the flow and heat transfer characteristics associated with the nozzle geometric configurations and offers practical help for the researchers and scientists working in the laser machining area.