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Article
Publication date: 12 May 2020

Barbara Dziurdzia, Maciej Sobolewski, Janusz Mikołajek and Sebastian Wroński

This paper aims to investigate voiding phenomena in solder joints under thermal pads of light-emitting diodes (LEDs) assembled in mass production environment by reflow soldering…

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Abstract

Purpose

This paper aims to investigate voiding phenomena in solder joints under thermal pads of light-emitting diodes (LEDs) assembled in mass production environment by reflow soldering by using seven low-voiding lead-free solder pastes.

Design/methodology/approach

The solder pastes investigated are of SAC305 type, Innolot type or they are especially formulated by the manufacturers on the base of (SnAgCu) alloys with addition of some alloying elements such as Bi, In, Sb and Ti to provide low-void contents. The SnPb solder paste – OM5100 – was used as a benchmark. The solder paste coverage of LED solder pads was chosen as a measure of void contents in solder joints because of common usage of this parameter in industry practice.

Findings

It was found that the highest coverage and, related to it, the least void contents are in solder joints formed with the pastes LMPA-Q and REL61, which are characterized by the coverage of mean value 93.13% [standard deviation (SD) = 2.72%] and 92.93% (SD = 2.77%), respectively. The void diameters reach the mean value equal to 0.061 mm (SD = 0.044 mm) for LMPA-Q and 0.074 mm (SD = 0.052 mm) for REL61. The results are presented in the form of histograms, plot boxes and X-ray images. Some selected solder joints were observed with 3D computer tomography.

Originality/value

The statistical analyses are carried out on the basis of 2D X-ray images with using Origin software. They enable to compare features of various solder pastes recommended by manufacturers as low voiding. The results might be useful for solder paste manufacturers or electronic manufacturing services.

Details

Soldering & Surface Mount Technology, vol. 32 no. 4
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 7 June 2018

Agata Skwarek, Balázs Illés, Krzysztof Witek, Tamás Hurtony, Jacek Tarasiuk, Sebastian Wronski and Beata Kinga Synkiewicz

This paper aims to investigate the quality and reliability of solder joints prepared from Pb-free alloys on direct bounded Cu (DBC) substrates. Two types of solder alloys were…

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Abstract

Purpose

This paper aims to investigate the quality and reliability of solder joints prepared from Pb-free alloys on direct bounded Cu (DBC) substrates. Two types of solder alloys were studied: Sn90.95Ag3.8Cu0.7Sb1.4Ni0.15Bi3.0, with a high melting point of 225°C, and Sn42Bi58, with low a melting point of 138°C.

Design/methodology/approach

Capacitor components of size 1806 were soldered on DBC substrates by using convection reflow soldering and vacuum vapor-phase soldering technologies. A part of the samples was subjected to the thermal shock test. The structure of the solder joints and the content of the voids were investigated using three-dimensional X-ray tomography. The mechanical strength of the joints was evaluated using the shear force test, and the microstructure of the joints was studied on metallographic cross sections by using scanning electron microscopy.

Findings

It was found that the number of voids is not related directly to the mechanical strength of the solder joints. The mechanical strength of the solder joints depends more on the amount of Ag3Sn precipitation, Au precipitation and the intermetallic layer in the solder joints. In some cases, the thermal shock test caused micro-cracks around the Au precipitation because of a mismatch of Au, AuSn4 and Sn in terms of coefficients of thermal expansion.

Originality/value

DBC substrates are usually used for power electronics, where the quality of the solder joints is even more important than in the case of commercial electronics.

Details

Soldering & Surface Mount Technology, vol. 30 no. 4
Type: Research Article
ISSN: 0954-0911

Keywords

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Article
Publication date: 6 October 2014

Andi Sebastian, Liz Fulop, Ann Dadich, Anneke Fitzgerald, Louise Kippist and Anne Smyth

The purpose of this paper is to call for strong medical co-leadership in transforming the Australian health system. The paper discusses how Health LEADS Australia, the Australian…

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Abstract

Purpose

The purpose of this paper is to call for strong medical co-leadership in transforming the Australian health system. The paper discusses how Health LEADS Australia, the Australian health leadership framework, offers an opportunity to engage medical clinicians and doctors in the leadership of health services.

Design/methodology/approach

The paper first discusses the nature of medical leadership and its associated challenges. The paper argues that medical leaders have a key role in the design, implementation and evaluation of healthcare reforms, and in translating these reforms for their colleagues. Second, this paper describes the origins and nature of Health LEADS Australia. Third, this paper discusses the importance of the goal of Health LEADS Australia and suggests the evidence-base underpinning the five foci in shaping medical leadership education and professional development. This paper concludes with suggestions on how Health LEADS Australia might be evaluated.

Findings

For the well-being of the Australian health system, doctors need to play an important role in the kind of leadership that makes measurable differences in the retention of clinical professions; improves organisational cultures; enhances the engagement of consumers and their careers; is associated with better patient and public health outcomes; effectively addresses health inequalities; balances cost effectiveness with improved quality and safety; and is sustainable.

Originality/value

This is the first article addressing Health LEADS Australia and medical leadership. Australia is actively engaging in a national approach to health leadership. Discussions about the mechanisms and intentions of this are valuable in both national and global health leadership discourses.

Details

Leadership in Health Services, vol. 27 no. 4
Type: Research Article
ISSN: 1751-1879

Keywords

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