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Article

F Sun, Zhen Pan, Yang Liu, Xiang Li, Haoyu Liu and Wenpeng Li

The purpose of this paper is to quickly manufacture full Cu3Sn-microporous copper composite joints for high-temperature power electronics applications and study the…

Abstract

Purpose

The purpose of this paper is to quickly manufacture full Cu3Sn-microporous copper composite joints for high-temperature power electronics applications and study the microstructure evolution and the shear strength of Cu3Sn at different bonding times.

Design/methodology/approach

In this paper, a novel structure of Cu/composite solder sheet/Cu was designed. The composite solder sheet was made of microporous copper filled with Sn. The composite joint was bonded by thermo-compression bonding under pressure of 0.6 MPa at 300°C. The microstructure evolution and the growth behavior of Cu3Sn at different bonding times were observed by electron microscope and metallographic microscope. The shear strength of the joint was measured by shear machine.

Findings

At initial bonding stage the copper atoms in the substrate and the copper atoms in the microporous copper dissolved into the liquid Sn. Then the scallop-liked Cu6Sn5 phases formed at the interface of liquid Sn/microporous copper and liquid Sn/Cu substrates. During the liquid Sn changing to Cu6Sn5 phases, Cu3Sn phases formed and grew at the interface of Cu6Sn5/Cu substrates and Cu6Sn5/microporous copper. After that the Cu3Sn phases continued to grow and the Cu3Sn-microporous copper composite joint with a thickness of 100 µm was successfully obtained. The growth rule of Cu3Sn was parabolic growth. The shear strength of the composite joints was about 155 MPa.

Originality/value

This paper presents a novel full Cu3Sn-microporous copper composite joint with high shear strength for high-temperature applications based on transient liquid phase bonding. The microstructure evolution and the growth behavior of Cu3Sn in the composite joints were studied. The shear strength and the fracture mechanism of the composite joints were studied.

Details

Soldering & Surface Mount Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0954-0911

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Article

Gui-sheng Gan, Liujie Jiang, Shiqi Chen, Yongqiang Deng, Donghua Yang, Zhaoqi Jiang, Huadong Cao, Mizhe Tian, Qianzhu Xu and Xin Liu

Low-Ag SAC solder will lead to a series of problems, such as increased the melting range and declined the solderability and so on. These research studies do not have too…

Abstract

Purpose

Low-Ag SAC solder will lead to a series of problems, such as increased the melting range and declined the solderability and so on. These research studies do not have too much impact on the improvement of solders’ performance but were difficult to achieve satisfactory results. It is urgent to develop new soldering technology to avoid the bottleneck of lead-free solder. low-temperature-stirring soldering and ultrasonic-assisted soldering was developed in the authors’ early work, but slag inclusion and pore would gather and grow up to lead decreasing of the shear strength. In this paper, Cu/SAC0307 +Zn power/Cu joints with ultrasonic-assisted at low-temperature was successfully achieved.

Design/methodology/approach

45um Zn-powder and SAC0307 No.4 solder powder were mixed to fill the Cu-Cu joint, and the content of Zn-powder were 0 and 5%, 7.5% and 10%, 12.5% and 15% respectively. During the soldering process under ambient atmosphere %252C the heating platform provided a constant 220%253 F and the ultrasonic vibrator applied a constant pressure of 4 MPa to the copper substrate. The soldering process was completed after holding 70 s at 300 W.

Findings

The Zn particles made the IMC at the joint interface and in the soldering seam from scallop-type Cu6Sn5 to flat-type Cu5Zn8. The shear strength of joints without Zn was only 12.43 MPa, the shear strength of joints with 10% Zn reached a peak of 34.25 MPa, and the shear strength of joints containing 10% Zn was 63.71% higher than that of joints without zinc particles, and then the shear strength decreased. In addition, with the increase of zinc content, the fracture mode of the joint changed from the brittle fracture of the original layered tears to the mixed tough and brittle fracture.

Originality/value

A new method that Zn micron-size powders and SAC0307 micron-size powders was mixed to fill the joint, and successfully achieved micro-joining of Cu/Cu under ultrasonic-assisted without flux at low-temperature.

Details

Soldering & Surface Mount Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0954-0911

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Article

Jiaqiang Chen

The main supporting frame of steel structure buildings is steel, and the beam-column joints of the steel structure directly affect the stability and strength of the…

Abstract

Purpose

The main supporting frame of steel structure buildings is steel, and the beam-column joints of the steel structure directly affect the stability and strength of the supporting frame.

Design/methodology/approach

This paper briefly introduced the beam-column joints which are used for ensuring the stability of buildings in the steel structure building, selected the fabricated beam-column joints which were different from the traditional welding methods, tested the fabricated beam-column joints with the reaction frame and jack and detected the influence of the thickness and length of the splice plate on the mechanical properties of joints.

Findings

The results showed that the joint stress and the displacement in the vertical direction increased under greater load no matter which kind of fabricated joint was used; under the same load, the thickness and length of the splice significantly affected the mechanical properties of joints, and the larger the thickness and length, the smaller the joint stress and displacement in the vertical direction.

Originality/value

To sum up, increasing the thickness or length of the splice plate of the fabricated joint can effectively improve the mechanical properties of joints.

Details

International Journal of Building Pathology and Adaptation, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2398-4708

Keywords

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Article

Deborah E. Swain and Patrick Roughen

This paper aims to describe how knowledge management (KM) in planning can support the sustainability of innovation in a hybrid, joint-use facility. The case study research…

Abstract

Purpose

This paper aims to describe how knowledge management (KM) in planning can support the sustainability of innovation in a hybrid, joint-use facility. The case study research studies ImaginOn, a 15 year-old children’s library and theater for young people in Charlotte, NC.

Design/methodology/approach

This research used KM model analysis of qualitative data about tacit-explicit knowledge, intellectual capital (IC) and cognitive modes of collaboration. Both historic documents and primary data (from field study observations, interviews and a questionnaire) were analyzed for informal KM practices. Semi-structured and unstructured interview questions about innovation were used.

Findings

This study found evidence of tacit knowledge sharing, the growth of IC and the operationalization of collaboration to promote innovation. Although traditional KM terms were not used by staff, an integrated model framework demonstrates how KM practices promote innovation in planning joint-use facilities.

Practical implications

Although a study of a diverse cultural collaboration rather than two libraries, the KM practices that supported innovation and collaboration in this hybrid, joint-use facility might be applied to libraries. Future KM model research on joint-use organizations could investigate merged businesses, government programs and non-profits.

Social implications

The library and theater institutions in ImaginOn impact the lives of children and parents in meaningful ways that support community understanding, art, diversity and social interaction.

Originality/value

Research on joint-use libraries began in the 1960s. This case study provides unique model analysis of KM practices in a hybrid, joint-use facility (a library and theater). The innovative success and sustainability of ImaginOn illustrates the application of KM for strategic planning and aligning IC and business assets.

Details

Journal of Knowledge Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1367-3270

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Article

Ming-Yue Xiong, Liang Zhang, Peng He and Wei-Min Long

The transistor circuit based on Moore's Law is approaching the performance limit. The three-dimensional integrated circuit (3-D IC) is an important way to implement More…

Abstract

Purpose

The transistor circuit based on Moore's Law is approaching the performance limit. The three-dimensional integrated circuit (3-D IC) is an important way to implement More than Moore. The main problems in the development of 3-D IC are Joule heating and stress. The stresses and strains generated in 3-D ICs will affect the performance of electronic products, leading to various reliability issues. The intermetallic compound (IMC) joint materials and structures are the main factors affecting 3-D IC stress. The purpose of this paper is to optimize the design of the 3-D IC.

Design/methodology/approach

To optimize the design of 3-D IC, the numerical model of 3-D IC was established. The Taguchi experiment was designed to simulate the influence of IMC joint material, solder joint array and package size on 3-D IC stress.

Findings

The simulation results show that the solder joint array and IMC joint materials have great influence on the equivalent stress. Compared with the original design, the von Mises stress of the optimal design was reduced by 69.96 per cent, the signal-to-noise ratio (S/N) was increased by 10.46 dB and the fatigue life of the Sn-3.9Ag-0.6Cu solder joint was increased from 415 to 533 cycles, indicating that the reliability of the 3-D IC has been significantly improved.

Originality/value

It is necessary to study the material properties of the bonded structure since 3-D IC is a new packaging structure. Currently, there is no relevant research on the optimization design of solder joint array in 3-D IC. Therefore, the IMC joint material, the solder joint array, the chip thickness and the substrate thickness are selected as the control factors to analyze the influence of various factors on the 3-D IC stress and design. The orthogonal experiment is used to optimize the structure of the 3-D IC.

Details

Soldering & Surface Mount Technology, vol. 32 no. 1
Type: Research Article
ISSN: 0954-0911

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Article

N. Brady and T.J. Ennis

Tensile pull strength tests were used to study the strength of solder joints of 25 mil gull wing leads on 132 pin quad flat pack components. The authors generated…

Abstract

Tensile pull strength tests were used to study the strength of solder joints of 25 mil gull wing leads on 132 pin quad flat pack components. The authors generated quadratic and linear models which can be used to predict the pull strength of a solder joint given its geometry. The shape parameters studied were stand‐off height between the lead and substrate, height of heel fillet, radius of curvature of heel fillet, length of heel fillet, height of solder at toe region, and thickness of solder on the lead. The most significant parameters in determining the tensile pull strength of the solder joint are the height and length of the heel fillet. A study was performed to quantify the effect of lead finish on the accuracy of these models. The lead finish was found to have a significant effect on the solder joint strength. The effect of lateral misregistration on the tensile pull strength of solder joints was also investigated. No correlation between the extent of lateral misregistration and joint pull strength has been found.

Details

Soldering & Surface Mount Technology, vol. 4 no. 1
Type: Research Article
ISSN: 0954-0911

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Article

Xiufeng Zhang, Huiqun Fu, Xitai Wang, Guanglin Li, Rong Yang and Ying Liu

This paper aims to find a new method that could be applied to the high and mid-grade prosthesis knee joint.

Abstract

Purpose

This paper aims to find a new method that could be applied to the high and mid-grade prosthesis knee joint.

Design/methodology/approach

Based on analysis, calculation, modeling, simulation and experimental study of the motion law of knee joint, this paper not only determines the structure and parameters of the knee joint and calculates the instantaneous center but also analyzes the stance stability and completes the optimization. With the help of experimental tests (fatigue test and gait curve test), the quality and performance of the designed knee joint is verified.

Findings

The experimental results show that the gait curve of the designed knee joint is much closer to health people. The designed prosthesis knee joint, with adjustable swing speed and gait curve which are close to health limb, has a better performance when compared to the ordinary knee joint with four-bar linkage structure.

Originality/value

This paper developed a prosthesis knee joint based on a novel design method that could be applied to the “high and mid” grade prosthesis knee joint and verified its function on an amputee performed the lower amputation, which could provide theoretical support for researches and designs related to prosthesis knee joint in future.

Details

Assembly Automation, vol. 36 no. 4
Type: Research Article
ISSN: 0144-5154

Keywords

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Article

Liang Du, Jia-Bo Feng, Hua Wang and Wei-jun Zhang

This paper aims to present the design and a prototype experiment of a robotic joint module for tokamak in-vessel manipulator-related research; the results will promote the…

Abstract

Purpose

This paper aims to present the design and a prototype experiment of a robotic joint module for tokamak in-vessel manipulator-related research; the results will promote the adaptation of current in-vessel inspection manipulator to achieve full tokamak in-vessel environment compatibility.

Design/methodology/approach

A flexible metallic bellow-enclosed working chamber is used to protect the main servo drive components, the active cooling method for high temperature protection and the servo control structure simplification for high radiation endurance. A joint module prototype is manufactured and tested under a similar in-vessel environmental condition for extreme condition protection validation and basic servo control ability evaluation.

Findings

The joint module prototype successfully survived the similar in-vessel environment tests and proved good mobility via closed-loop servo control. A conceptual design of a serial linkage manipulator with joint module structure is proposed for future in-vessel inspection manipulator development.

Originality/value

The proposed joint module uses common industrial servo components to achieve its full extreme in-vessel environment compatibility. Different from traditional metallic bellow application in a vacuum environment to produce a linear movement result, the proposed joint module aims to achieve rotating movement directly from the metallic bellow structure, thereby reducing the joint structure space requirement, simplifying the vacuum environment movement transmission structure and increasing the vacuum environment compatibility degree.

Details

Industrial Robot: An International Journal, vol. 45 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

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Article

M. Kitano, S. Kawai and I. Shimizu

Long‐term fatigue life estimation for solder joints of surface mount IC packages is studied through elasto‐plastic stress analysis and temperature cycling tests. Strain on…

Abstract

Long‐term fatigue life estimation for solder joints of surface mount IC packages is studied through elasto‐plastic stress analysis and temperature cycling tests. Strain on the solder joint induced by thermal expansion mismatch between package and substrate has been analysed by considering elasto‐plastic behaviour of the solder and by treating leads as rigid frames. Validity of the analysis has been confirmed by stiffness measurement of the soldered leads. Dynamic shear stress‐strain relationships of type 60Sn/40Pb solder are obtained as a function of temperature and frequency using hollow solder specimens of 15 mm in diameter and hollow solder joint specimens with the same diameter in the temperature range of −60°C to 150°C with frequencies of 0.01 Hz and 0.3 Hz. Fatigue tests are carried out for the solder specimens and the solder joint specimens under shear strain control and for the solder joints of the real IC packages under displacement control. All fatigue tests are conducted at room temperature with a frequency of 1 Hz. Fatigue test data of solder, solder joint and the solder joints of real IC packages fall in the same scatter band in the stra'un‐cycles to failure diagram. A fatigue life estimation model for solder joints of surface mount IC packages is proposed, which is derived by combining the strain calculated by the elasto‐plastic analysis and the fatigue data. To apply the proposed model to IC packages, the temperature cycling test between −55°C and +150°C is performed for two IC packages with different lead designs mounted on two different substrates (ceramics and glass‐epoxy). It is found that the fatigue life of solder joints by the temperature cycling test can be estimated by the proposed fatigue life estimation model. The proposed method is viable because it has sufficient accuracy with a cost of less than 1/100 when compared with the finite element method.

Details

Soldering & Surface Mount Technology, vol. 1 no. 2
Type: Research Article
ISSN: 0954-0911

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Article

Mariana D. Banea, Lucas F.M. da Silva and Raul D.S.G. Campilho

The purpose of this paper is to provide an insight into the techniques which are used and developed for adhesive bulk and joint specimens manufacturing.

Abstract

Purpose

The purpose of this paper is to provide an insight into the techniques which are used and developed for adhesive bulk and joint specimens manufacturing.

Design/methodology/approach

After a short introduction, the paper discusses various techniques for adhesive bulk and joint specimens manufacturing and highlights their advantages and limitations. A number of examples in the form of different bulk and joint specimens of different types of adhesives are used to show the methods for determining the adhesive's mechanical properties needed for design in adhesive technology. In order to predict the adhesive joint strength, the stress distribution and a suitable failure criterion are essential. If a continuum mechanics approach is used, the availability of the stress‐strain curve of the adhesive is sufficient (the bulk tensile test or the TAST test is used). For fracture mechanics‐based design, mode I and mode II toughness is needed (DCB and ENF tests are used). Finally, single lap joints (SLJs) are used to assess the adhesive's performance in a joint.

Findings

Before an adhesive can be specified for an application, screening tests should be conducted in order to compare and evaluate the various adhesion parameters. Properties of adhesives can vary greatly and an appropriate selection is essential for a proper joint design. Thus, to determine the stresses and strains in adhesive joints in a variety of configurations, it is necessary to characterize the adhesive behaviour in order to know its mechanical properties. A great variety of test geometries and specimens are used to obtain adhesive properties. However, for manufacturing of adhesive bulk specimens and joints necessary for use in these tests, properly, moulds should be designed.

Originality/value

The paper summarises the main methods of preparing adhesive bulk and joint specimens and the test methods for determining the mechanical properties needed for design in adhesive technology. Emphasis is given to the preparation of specimens of suitable quality for mechanical property determination and the moulds designed for this purpose.

Details

Assembly Automation, vol. 32 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

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