Optimization of solder paste quantity considering the properties of solder joints

2017 ◽  
Vol 29 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Martin Hirman ◽  
Frantisek Steiner
Keyword(s):  
Shear Strength ◽  
Electrical Resistance ◽  
Solder Paste ◽  
Comprehensive Overview ◽  
Content Type ◽  
Fishbone Diagram ◽  
Expert Analysis ◽  
Recommendations For Practice ◽  
Electronic Assemblies ◽  
Soldered Joint

Purpose The purpose of this paper is to find an optimum between the quantity of solder paste and the desired properties of the soldered joint. A reduction of solder paste quantity is recognized as an opportunity to save money. On the other hand, the quantity of solder paste significantly influences the final properties of the soldered joint. The purpose is also to design recommendations for manufacturers of electronic assemblies. Design/methodology/approach The processing of the paper was initiated by a literature review. The expert analysis was the next step. The result of analysis was a fishbone diagram. Subsequently, the experiment was designed. Seven types and three volume of solder pastes and two aperture shapes of the stencil were used. The measured parameters were mechanical strength, electrical resistance, voids area and intermetallic compound (IMC) thicknesses. The results of the experiment were evaluated and recommendations for practice were defined. Findings The carried out research has confirmed the influence of solder paste quantity on the shear strength, electrical resistance, voids area and IMC thickness of solder joint. The article presents the results achieved for solders Sn42Bi58, Sn42Bi57.6Ag0.4, SnAg3.0Cu0.5, SnCu0.7Ag1.0NiGe, SnAg3.5Bi0.5In8.0 and Sn62.5Pb36.5Ag1.0. Reduction of solder paste quantity down to 74 per cent (i.e. one quarter of quantity) decreases mechanical shear strength less than 10 per cent. Recommendations relating to the optimal reduction of solder paste quantity have been designed for each solder paste. Originality/value Contribution of the paper is impact assessment of solder paste quantity on the properties of the soldered joint. It was carried out a large number of experiments and measurements which verify this effect. Such a comprehensive overview of the results is not yet available in the literature. Recommendations for manufacturers of electronic assemblies are also the benefit of article.

Effect of ultrasonic vibration on interfacial reaction of Ni/Sn/Ni soldered joint

2019 ◽  
Vol 32 (2) ◽  
pp. 73-81
Author(s):  
Yun Liu ◽  
Weiyuan Yu ◽  
Xuemin Sun ◽  
Fengfeng Wang
Keyword(s):  
Shear Strength ◽  
Ultrasonic Vibration ◽  
Grain Morphology ◽  
Electronics Packaging ◽  
Dispersion Strengthening ◽  
Shear Tests ◽  
Content Type ◽  
Ultrasonic Assisted ◽  
Surface Microstructures ◽  
Soldered Joint

Purpose This paper aims to investigate the effect of ultrasonic vibration (USV) on the evolution of intermetallic compounds (IMCs), grain morphology and shear strength of soldered Ni/Sn/Ni samples. Design/methodology/approach The Ni/Sn/Ni joints were obtained through ultrasonic-assisted soldering. The formation of IMCs, their composition, grain morphology and the fractured-surface microstructures from shear tests were characterized using scanning electron microscopy and energy-dispersive x-ray spectroscopy. Findings Without USV, a planar interfacial Ni3Sn4 layer was formed at the Ni/Sn interface, and a few Ni3Sn4 grains were distributed in the soldered joint. The morphology of these grains was needle-shaped. With USV, several grooves were formed at the interfacial Ni3Sn4 layer due to ultrasonic cavitation. Some deepened grooves led to “neck” connections at the roots of the Ni3Sn4 grains, which accelerated the strong detachment of Ni3Sn4 from the substrate. In addition, two types of Ni3Sn4 grains, needle-shaped and granular-shaped, were observed at the interface. Furthermore, the shear strength increased with longer USV time, which was attributed to the thinning of the interfacial IMC layers and dispersion strengthening from the Ni3Sn4 particles distributed evenly in the joint. Originality/value The novelty of the paper is the detailed study of the effect of USV on the morphology, size changes of interfacial IMC and joint strength. This provides guidance for the application of ultrasonic-assisted soldering in electronics packaging.

FINRA’s disciplinary actions in 2017: increased restitution ordered with minimal changes in number of cases

2018 ◽  
Vol 19 (2) ◽  
pp. 19-23
Author(s):  
Brian Rubin ◽  
Adam Pollet
Keyword(s):  
Money Laundering ◽  
Design Methodology ◽  
Disciplinary Actions ◽  
Financial Industry ◽  
Electronic Communications ◽  
Content Type ◽  
The Past ◽  
Expert Analysis ◽  
Research Analysts ◽  
Practical Implications

Purpose The purpose of this paper is to analyze the Financial Industry Regulatory Authority’s (FINRA) 2017 disciplinary actions, the issues that resulted in the most significant fines and restitution and the emerging enforcement trends from 2017 and beyond. Design/methodology/approach The approach of this paper discusses the disciplinary actions in 2017 and prior years, details the top 2017 enforcement issues measured by total fines assessed, including anti-money laundering, trade reporting, electronic communications, books and records, research analysts and research reports, and explains current enforcement trends, including restitution, suitability cases and technological issues. Findings In 2017, restitution more than doubled from the prior year, resulting in the fourth highest total sanctions (fines combined with restitution and disgorgement) assessed by FINRA over the past 10 years. Practical implications Firms and their representatives should heed the trends in both the substantial restitution FINRA is ordering and the related enforcement issues in the cases FINRA has brought. Originality/value This paper provides expert analysis and guidance from experienced securities enforcement lawyers.

COVID-19 considerations for SEC cybersecurity guidance, disclosure, enforcement, and parallel proceedings: navigating the new normal

2020 ◽  
Vol 21 (2/3) ◽  
pp. 111-126
Author(s):  
Aldo M. Leiva ◽  
Michel E. Clark
Keyword(s):  
Securities And Exchange Commission ◽  
Effective Vaccine ◽  
Resource Reallocation ◽  
Securities Litigation ◽  
Public Companies ◽  
Content Type ◽  
Business Operations ◽  
Expert Analysis ◽  
Securities Industry ◽  
Remote Operations

Purpose To examine the COVID-19 pandemic’s effects on regulated entities within the context of cybersecurity, US Securities and Exchange Commission (SEC) compliance, and parallel proceedings. Design/methodology/approach Describes the SEC’s ability to conduct its operations within the telework environment, its commitment and ability to monitor the securities market, its enhanced monitoring of the adverse effects of SEC-regulated companies from COVID-19, its guidance to public companies of disclosure obligations related to cybersecurity risks and incidents, the SEC Office of Compliance and Examinations’s (OCIE’s) focus on broker-dealers’ and investment advisories’ cybersecurity preparedness, the role and activities of the SEC Division of Enforcement’s Cyber Unit, and parallel proceedings on cyberbreaches and incidents by different agencies, branches of government or private litigants. Findings SEC-regulated entities face many challenges in trying to maintain their ongoing business operations and infrastructure due to severe financial pressures, the threat of infection to employees and customers, and cybersecurity risks posed by remote operations from hackers and fraudsters. The SEC has reemphasized that its long-standing focus on cybersecurity and resiliency within the securities industry will continue, including ongoing vigilance over companies’ efforts to identify, assess, and address the inherent, heightened cybersecurity risks of teleworking and the resource reallocation that business need to sustain their operations until a safe and effective vaccine is developed for COVID-19. Originality/value Expert analysis and guidance from experienced lawyers with expertise in securities, litigation, government enforcement, information technology, data protection, privacy and cybersecurity.

Numerical analysis of the shear strength of circular reinforced concrete columns subjected to cyclic lateral loads using linear genetic programming

2020 ◽  
Vol 37 (7) ◽  
pp. 2517-2537
Author(s):  
Mostafa Rezvani Sharif ◽  
Seyed Mohammad Reza Sadri Tabaei Zavareh
Keyword(s):  
Numerical Modeling ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Genetic Programming ◽  
Linear Genetic Programming ◽  
Rc Columns ◽  
Content Type ◽  
Alternative Approach ◽  
Engineering Problems

Purpose The shear strength of reinforced concrete (RC) columns under cyclic lateral loading is a crucial concern, particularly, in the seismic design of RC structures. Considering the costly procedure of testing methods for measuring the real value of the shear strength factor and the existence of several parameters impacting the system behavior, numerical modeling techniques have been very much appreciated by engineers and researchers. This study aims to propose a new model for estimation of the shear strength of cyclically loaded circular RC columns through a robust computational intelligence approach, namely, linear genetic programming (LGP). Design/methodology/approach LGP is a data-driven self-adaptive algorithm recently used for classification, pattern recognition and numerical modeling of engineering problems. A reliable database consisting of 64 experimental data is collected for the development of shear strength LGP models here. The obtained models are evaluated from both engineering and accuracy perspectives by means of several indicators and supplementary studies and the optimal model is presented for further purposes. Additionally, the capability of LGP is examined to be used as an alternative approach for the numerical analysis of engineering problems. Findings A new predictive model is proposed for the estimation of the shear strength of cyclically loaded circular RC columns using the LGP approach. To demonstrate the capability of the proposed model, the analysis results are compared to those obtained by some well-known models recommended in the existing literature. The results confirm the potential of the LGP approach for numerical analysis of engineering problems in addition to the fact that the obtained LGP model outperforms existing models in estimation and predictability. Originality/value This paper mainly represents the capability of the LGP approach as a robust alternative approach among existing analytical and numerical methods for modeling and analysis of relevant engineering approximation and estimation problems. The authors are confident that the shear strength model proposed can be used for design and pre-design aims. The authors also declare that they have no conflict of interest.

Environmental tests of embedded thin- and thick-film resistors in comparison to chip resistors

Circuit World ◽  
2014 ◽  
Vol 40 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Wojciech Steplewski ◽  
Andrzej Dziedzic ◽  
Janusz Borecki ◽  
Grazyna Koziol ◽  
Tomasz Serzysko
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Electrical Resistance ◽  
Printed Circuit Boards ◽  
Base Material ◽  
Forming Process ◽  
Content Type ◽  
Thin Film Resistors ◽  
Embedded Resistors ◽  
The Impact

Purpose – The purpose of this paper is to investigate the influence of parameters of embedded resistive elements manufacturing process as well as the influence of environmental factors on their electrical resistance. The investigations were made in comparison to the similar constructions of discrete chip resistors assembled to standard printed circuit boards (PCBs). Design/methodology/approach – The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon-silver inks as well as chip resistors in 0402 and 0603 packages. The polymer thick-film resistive films were screen-printed on the several types finishing materials of contact terminations such as copper, silver, and gold. To determine the sensitivity of embedded resistors versus standard assembled chip resistors on environmental exposure, the climatic chamber was used. The measurements of resistance were carried out periodically during the tests, and after the exposure cycles. Findings – The results show that the change of electrical resistance of embedded resistors, in dependence of construction and base material, is different and mainly not exceed the range of 3 per cent. The achieved results in reference to thin-film resistors are comparable with results for standard chip resistors. However, the results that were obtained for thick-film resistors with Ag and Ni/Au contacts are similar. It was not found the big differences between resistors with and without conformal coating. Research limitations/implications – The studies show that embedded resistors can be used interchangeably with chip resistors. It allows to save the area on the surface of PCB, occupied by these passive elements, for assembly of active elements (ICs) and thus enable to miniaturization of electronic devices. But embedding of passive elements into PCB requires to tackle the effect of each forming process steps on the operational properties. Originality/value – The technique of passive elements embedding into PCB is generally known; however, there are no detailed reports on the impact of individual process steps and environmental conditions on the stability of their electrical resistance. The studies allow to understand the importance of each factor process and the mechanisms of operational properties changes depending on the used materials.

STUDY OF THE INFLUENCE OF NON-COVALENT MODIFIERS ON THE STRUCTURE AND PROPERTIES OF POLYMER FILAMENTS FOR FDM-PRINTING BASED ON ABS-PLASTIC AND CARBON NANOPARTICLES

2021 ◽  
pp. 36-44
Author(s):  
A.A. Pykhtin ◽  
◽  
A.E. Sorokin ◽  
S.A. Larionov ◽  
S.L. Lonskii ◽  
...  
Keyword(s):  
Shear Strength ◽  
Water Absorption ◽  
Electrical Resistance ◽  
Carbon Nanoparticles ◽  
Structure And Properties ◽  
Technological Parameters ◽  
Modified Polymer

The paper presents the results of a study of the effect of non-covalent modifiers on the structure and properties of polymer filaments for FDM-printing based on ABS-plastic and carbon nanoparticles. The dependences of the characteristics of nanocomposites and filaments based on them to the type of functionalization have been established. The effect of the concentration of CNTs on the hardness, water absorption, electrical resistance, and shear strength for modified polymer filament has been investigated. The optimal formulations and technological parameters of FDM-printing of templates have been determined.

Accurate composition dependent thermo mechanical lifetime estimation of hour glass type solder joint in electronic assemblies

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Leonid Anatolevich Olenev ◽  
Rafina Rafkatovna Zakieva ◽  
Nina Nikolaevna Smirnova ◽  
Rustem Adamovich Shichiyakh ◽  
Kirill Aleksandrovich Ershov ◽  
...  
Keyword(s):  
Finite Element ◽  
Chemical Composition ◽  
Solder Joint ◽  
Design Methodology ◽  
Lifetime Estimation ◽  
Creep Tests ◽  
Content Type ◽  
Element Simulation ◽  
Glass Type ◽  
Electronic Assemblies

Purpose This study aims to present a more accurate lifetime prediction model considering solder chemical composition. Design/methodology/approach Thermal cycling and standard creep tests as well as finite element simulation were used. Findings The study found lower error in the solder joint lifetime evaluation. The higher the Ag content is, the higher the lifetime is achieved. Originality/value It is confirmed.

A framework to guide the implementation of lean management in emergency department

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Anna Tiso ◽  
Maria Crema ◽  
Chiara Verbano
Keyword(s):  
Emergency Department ◽  
Literature Review ◽  
Descriptive Analysis ◽  
Lean Management ◽  
Comprehensive Overview ◽  
Content Type ◽  
Managerial Practices ◽  
Prisma Statement ◽  
Meta Analyses ◽  
Tools And Techniques

PurposeThe paper aims at enriching the knowledge of the application of lean management (LM) in emergency department (ED), structuring the methodology for implementing LM projects and summarizing the relevant dimensions of LM adoption in ED.Design/methodology/approachIn accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, a systematic literature review has been performed, extracting a database of 34 papers. To answer the research purpose, a descriptive and content analyses have been carried out.FindingsThe descriptive analysis demonstrates that the dealt topic is worldwide emerging and multidisciplinary as it arouses interest by medical and engineering communities. Despite the heterogeneity in the adopted methodology, a framework can be grasped from the literature review. It points out the phases and activities, the tools and techniques and the enablers to be considered for guiding the developing of LM project in ED.Originality/valueThis paper provides a comprehensive overview on how to adopt LM in ED, contributing to fill in the gap emerged in the literature. From a practical perspective, this paper provides healthcare managers with a synthesis of the best managerial practices and guidelines in developing a LM project in ED.

Tourism public-private partnership (PPP) projects: an exploratory-sequential approach

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Marwa Ghanem ◽  
Ibrahim Elshaer ◽  
Samar Saad
Keyword(s):  
Interpersonal Relationships ◽  
Service Providers ◽  
Stakeholder Management ◽  
Comprehensive Overview ◽  
Sequential Approach ◽  
Essential Information ◽  
Content Type ◽  
The Government ◽  
The Relationship

Purpose This study aims to address the absence of a thorough understanding of commitment in tourism public-private partnerships (PPP) by exploring antecedents of PPP commitment and their underpinning relationships in regard to the destination management system (DMS). Design/methodology/approach An empirical investigation of the case of the Egyptian DMS, a PPP which was forsaken by the government partner and which subsequently failed. Qualitative and quantitative approaches are used for a comprehensive overview of the researched phenomena pertaining to external and internal stakeholders. Findings The results indicated that stakeholder management, relational capital, perceived benefits and stakeholder capabilities could influence intentions to commit to a tourism PPP project. Also, the latter three factors were found to mediate the relationship between stakeholder management and long-term PPP commitment. The results also shed light on the important aspects of non-contractual, interpersonal relationships between internal and external PPP stakeholders. Originality/value This research pioneers inquiries on the commitment of Tourism PPP/DMS projects and its possible drivers in a non-Western context. Also, this study contributes to knowledge by exploring the relationship within and between internal (partners) and external (e.g. local service providers) stakeholder groups and provided evidence on the crucial role of both on long-term PPP commitment and success. The current study has a few significant contributions to the PPP literature regarding the commitment and success of PPP in the complicated environments in which tourism PPP projects are operated. Moreover, this study offers essential information and practices for improving partner relationships with external stakeholders.

Protection of railway infrastructure objects against electrical corrosion

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liudmyla Trykoz ◽  
Svetlana Kamchatnaya ◽  
Dmytro Borodin ◽  
Armen Atynian ◽  
Roman Tkachenko
Keyword(s):  
Leakage Current ◽  
Electrical Resistance ◽  
Electrical Current ◽  
Leakage Currents ◽  
Destructive Effect ◽  
Accelerated Corrosion ◽  
Content Type ◽  
Pedestrian Bridges ◽  
Railway Infrastructure ◽  
Bridge Structures

Purpose The purpose of this paper is to develop a technological method of protection against electrical corrosion. One more way to protect the objects is to prevent the electrical current from getting to them. For example, railway objects are surrounded with a material with raised electrical resistance. Design/methodology/approach The railway infrastructure objects (foundations, contact-line supports, reinforced concrete sub-bases, bridge structures, pipelines of engineering networks, supports of passenger platforms and pedestrian bridges, concrete plinth walls of station buildings) are subjected to destruction due to the action of electrical current. One of destruction factors is a corrosion of the concrete constructions which is caused by the leakage current action. Findings Leakage currents and stray currents bypass the structure of supports of high passenger platforms or pipes of engineering networks. These currents spread by the line with the least resistance outside of the structures. Research limitations/implications Electrical leakage current from the rails gets into such structures through sleepers, ballast and soil and leads to accelerated corrosion leaching of concrete. Practical implications The constructions are protected against the destructive effect of electrical corrosion on the metal or concrete of the structure. This scheme is suitable for the construction and reconstruction of railway structures which operate on electrified sections of railways. Originality/value Schemes of technological solution are proposed for protection of foundations, supports of high passenger platforms, pipelines of engineering networks, etc. For this, the arrangement of soil-contained screens with big electrical resistance is suggested.

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