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Article
Publication date: 10 April 2019

Qingchao Sun, Xiaokai Mu, Bo Yuan, Jiawen Xu and Wei Sun

This paper aims to distinguish the relationship between the morphology characteristics of different scales and the contact performance of the mating surfaces. Also, an…

Abstract

Purpose

This paper aims to distinguish the relationship between the morphology characteristics of different scales and the contact performance of the mating surfaces. Also, an integrated method of the spectrum analysis and the wavelet transform is used to separate the morphology characteristics of the actual machined parts.

Design/methodology/approach

First, a three-dimensional (3D) surface profilometer is used to obtain the surface morphology data of the actual machined parts. Second, the morphology characteristics of different scales are realized by the wavelet analysis and the power spectral density. Third, the reverse modeling engineering is used to construct the 3D contact models for the macroscopic characteristics. Finally, the finite element method is used to analyze the contact stiffness and the contact area of the 3D contact model.

Findings

The contact area and the nominal contact pressure Pn have a nonlinear relationship in the whole compression process for the 3D contact model. The percentage of the total contact area of the macro-scale mating surface is about 70 per cent when the contact pressure Pn is in the range of 0-100 MPa, and the elastic contact area accounts for the vast majority. Meanwhile, when the contact pressure Pn is less than 10MPa, the influence factor (the relative error of contact stiffness) is larger than 50 per cent, so the surface macro-scale morphology has a weakening effect on the normal contact stiffness of the mating surfaces.

Originality/value

This paper provides an effective method for the multi-scale separation of the surface morphology and then lays a certain theoretical foundation for improving the surface quality of parts and the morphology design.

Details

Engineering Computations, vol. 36 no. 3
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 24 April 2018

B. Chen, Peisheng Liu and J.H. Chen

With the nickel foam made by the technique of electrodeposition on polymer foam, the purpose of this paper is to investigate the influence of several deferent processes on…

Abstract

Purpose

With the nickel foam made by the technique of electrodeposition on polymer foam, the purpose of this paper is to investigate the influence of several deferent processes on the surface morphology and the specific surface area of this porous product.

Design/methodology/approach

The surface morphologies of the nickel foam were examined by SEM. The specific surface area of the porous product was measured by gas (N2) permeability method and also calculated by the reported formula.

Findings

The nickel foam from sintering in NH3 decomposition atmosphere at 850°C will achieve the same specific surface area as that at 980°C, whether this porous structure after electrodeposition comes through direct sintering in NH3 decomposition atmosphere, or through burning in air at 600°C for 4 min beforehand then the same reductive sintering.

Originality/value

There have been some studies on the preparation and application of nickel foam, but few works focus on the processing influence on the specific surface of this porous product. The present work provides the investigations on the difference of the product made under different producing conditions, and the influence of several deferent processes on the specific surface area of the product.

Details

Multidiscipline Modeling in Materials and Structures, vol. 14 no. 4
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 29 April 2014

Seok-Hwan Huh, Kang-Dong Kim and Keun-Soo Kim

The purpose of this paper is to evaluate the relationship between the Cu trace and epoxy resin and to check the validity of surface and interfacial cutting analysis system…

Abstract

Purpose

The purpose of this paper is to evaluate the relationship between the Cu trace and epoxy resin and to check the validity of surface and interfacial cutting analysis system (SAICAS) by comparing its results to those of the 90° peel test.

Design/methodology/approach

In this study, the effects of surface morphology on the adhesion strength were studied for a Cu/epoxy resin system using a SAICAS. In order to evaluate the peel strength of the sample, the curing degree and surface morphology of the epoxy resin were varied in the Cu/epoxy resin system.

Findings

The results indicated that the peel strength is strongly affected by the curing degree and the surface morphology of the epoxy layer. As the pre-cure time increased, the interactions between the epoxy resin and permanganate during the adhesion promotion process decreased, which decreased the surface roughness (Ra) of the resin. Therefore, the surface roughness of the epoxy resin decreased with increasing pre-cure time. The curing degree was calculated with the FTIR absorption peak (910 cm−1) of the epoxy groups. The high curing degree for the epoxy resin results in a coral-like morphology that provides a better anchoring effect for the Cu trace and a higher interfacial strength.

Research limitations/implications

It is necessary to study the further adhesion strength, i.e. the friction energy, the plastic deformation energy, and the interfacial fracture energy, in micro- and nanoscale areas using SAICAS owing to insufficient data regarding the effects of size and electroplating materials.

Originality/value

From findings, it is found that measuring the peel strength using SAICAS is particularly useful because it makes the assessment of the peel strength in the Cu/epoxy resin system of electronic packages possible.

Details

Circuit World, vol. 40 no. 2
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 12 March 2018

Yuan Wang

The main purpose of this study is to enhance bio-tribological properties of Ti6Al4V and the surface-modified layers of Ni+/N+-implanted Ti6Al4V alloy, bionic texturing was…

Abstract

Purpose

The main purpose of this study is to enhance bio-tribological properties of Ti6Al4V and the surface-modified layers of Ni+/N+-implanted Ti6Al4V alloy, bionic texturing was done on Ti6Al4V surface.

Design/methodology/approach

The phase compositions and nano-hardness of the surface-modified layers of the samples have been analyzed by X-ray diffractometer and Nano Indenter, respectively. This paper has conducted bio-tribological tests under artificial saliva, sodium hyalurate and sodium hyalurate +γ-globulin by micro tribology multifunction tribometer, with ZrO2 ball/modified layer as the friction pair. S-3000N scanning electron microscope has been used to analyze the morphology of the surface-modified layers and scratches of the ones after the bio-tribological tests.

Findings

The results show that the surface-modified layers were mainly composed of Ti2Ni and Ti2N. Moreover, bionic texturing can obviously increase the contents of Ti2Ni and Ti2N that were formed on the surface of Ni+/N+-implanted Ti6Al4V alloy, and enhance the nano-hardness of the surface-modified layers. It could also reduce the friction coefficients of the surface-modified layers, and render the modified layers more wear-resistant.

Originality/value

The surface bio-tribological properties of Ti6Al4V have been enhanced by ion implantation technique and bionic texturing in this paper; this provided a new method for the research of related fields.

Details

Industrial Lubrication and Tribology, vol. 70 no. 2
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 14 September 2015

Chuanjun Liao, Xibao Xu, Hongrong Fang, Hongrui Wang and Man Man

The purpose of this paper is to develop a leakage model of metallic static seals, which can be used to accurately predict the leakage rate and study the corresponding seal…

Abstract

Purpose

The purpose of this paper is to develop a leakage model of metallic static seals, which can be used to accurately predict the leakage rate and study the corresponding seal characteristics. The metallic static seal is effectively applied to severe rugged environments where conventional seals cannot meet the needs. More research efforts for deepening the understanding of its seal characteristics are important for its effective and safe applications, of which the study about its leak is one key component.

Design/methodology/approach

In the microscopic observations of the turning surface that is general in the processing of flange surfaces, it is found that the spiral morphology is dominant, which had been also obtained by other researches. There are two potential leakage paths for the flange surface of spiral morphology, one is the radial direction perpendicular to the spiral ridges and the other is the circumferential direction along the spiral groove. Based on the microgeometry characteristics of spiral morphology, the micromorphology of turning flange surface is simplified for the calculation of leakage rate, and the simplified methods of the radial and circumferential leakage paths are presented separately. The topography of flange surface studied in this paper is actually measured, and the Abbott bearing surface curve is adopted to represent the micro-profiles parameters. The radial and circumferential leakage models are further developed based on the assumption of laminar flow of the viscous compressible gas.

Findings

The experiments used to verify the leakage models were carried out, and the experimental values are well agreed with the calculated values. As the contact pressure increases, the change rules of both radial and circumferential leakage rates are obtained and the obvious transition from radial leak to circumferential leak can be found. Using the proposed leakage models, the effects of the key micro-profiles parameters on the leakage rates are studied, and some specific conclusions are given simultaneously, which are favorable for the theoretical study and practical application of the metallic static seal.

Practical implications

By the interpretations of the micromorphology characteristics of turning flange surface, the leakage mechanism of the metallic static seal is further made clear. The proposed leakage model reveals the relationships between the key micro-profiles parameters and some sealing performances about the leakage and can predict the leakage rates of the metallic static seal used in various working conditions.

Originality/value

For the metallic static seal, the simplification of the radial leakage path and the radial leakage model are put forward for the first time, so the total leakage model can be systematically reported based on the micromorphology characteristics of turning flange surface. The effects of the key micro-profiles parameters on the seal behaviors including of the leak rate, critical contact pressure and transition from radial leak to circumferential leak etc are also clarified firstly.

Details

Industrial Lubrication and Tribology, vol. 67 no. 6
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 25 June 2020

Yang Tian, Dacian Tomus, Aijun Huang and Xinhua Wu

Limited research has attempted to reveal the different modes of the melt pool formation in additive manufacturing. This paper aims to study the mechanisms of surface

Abstract

Purpose

Limited research has attempted to reveal the different modes of the melt pool formation in additive manufacturing. This paper aims to study the mechanisms of surface roughness formation, especially on the aspect of melt pool formation which determine the surface profile and consequently significantly influence the surface roughness.

Design/methodology/approach

In this study, the conditions under which different modes of melt pool formation (conduction mode and keyhole mode) occur for the case of as-fabricated Hastelloy X using direct metal laser solidification (DMLS) are derived and validated experimentally. Top surfaces of uni-directionally built samples under various processing conditions are cut, grinded, polished and etched to reveal their individual melt pool morphologies. Similarly, up-skin (slope angle < 90°) and down-skin (slope angle > 90°) melt pool morphologies are also investigated to compare the differences. Surface tension gradients and resultant Marangoni flow, which dominate the melt flow in the melt pool, is also calculated to help better evaluate the melt pool shape forming.

Findings

Two types of melt pool formation modes are dominating in DMLS: conduction mode and keyhole mode. Melt pool formed by conduction mode generally has an aspect ratio of 1:2 (depth vs width) and is in elliptical shape. Appropriate selection of scanning laser power and speed are required to maintain a low characteristic length and width ratio to prevent ballings. Melt pool formed by keyhole mode has an aspect ratio of 1:1 or less. High-energy contour promotes formation of key-hole-shaped melt pool which fills the gaps between layers and smoothens the up-skin surface roughness. Low-energy contour scan is necessary for down-skin surface to form small melt pool profiles and achieve low Ra.

Originality/value

This paper provides valuable insight into the origins of surface quality problem of DMLS, which is a very critical issue for upgrading the process for manufacturing real components. This paper helps promote the understanding of the attributes and capabilities of this rapidly evolving three-dimensional printing technology and allow appropriate control of processing parameters for successful fabrication of components with sound surface quality.

Details

Rapid Prototyping Journal, vol. 26 no. 8
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 13 March 2017

Wengang Chen, Xueyuan Liu and Lili Zheng

This paper aims to clarify the friction properties of 304 steel surface modification. The surface modification includes laser texturing processing and nitriding treatment…

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Abstract

Purpose

This paper aims to clarify the friction properties of 304 steel surface modification. The surface modification includes laser texturing processing and nitriding treatment on 304 steel surface, and then the friction properties’ test was conducted on different friction directions and different upper test samples by using microfriction and wear testing machine.

Design/methodology/approach

The diameter and spacing of 100-, 150-, 200-, 300-μm pit array on the surface of 304 steel were calculated using a M-DPSS-50 semiconductor laser device. Then, the textured surface was nitriding-treated using a nitriding salt bath device. The chemical composition, surface morphology and surface microhardness of the composite-modified surface were measured by X-ray diffraction and by using an optical microscope and a microhardness tester. The tribological characteristics of the composite-modified surface were tested by MRTR microcomputer-controlled multifunctional friction and wear testing machine.

Findings

The result showed that a rule pit texture surface was obtained by the texture processing. The microhardness of nitriding treatment surface reached 574.27HV0.1, which significantly higher than 222.58HV0.1 of 304 steel. The composite-modified surface has excellent anti-friction and wear resistance properties when the upper specimen was GCr15 steel and ZrO2, respectively. The composite-modified surface has excellent anti-friction and anti-wear properties after long time friction under different angles. However, the friction coefficient and wear morphology of the friction pairs are not affected by the friction angle.

Research limitations/implications

Because of the chosen research approach, the research results may lack generalizability. Therefore, researchers are encouraged to test the proposed propositions further.

Practical implications

The paper conducted a systematic study of the tribological characteristics of 304 steel composite modification surface and provided a good basis for the extensive application of 304 steel.

Social implications

The study provides a good basis for the extensive application of 304 steel.

Originality/value

This paper fulfils an identified need to study the extensive application of 304 steel.

Details

Industrial Lubrication and Tribology, vol. 69 no. 2
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 19 October 2015

Alberto Boschetto and Luana Bottini

The purpose of this paper is to study the integration between this technology and barrel finishing (BF) operation to improve part surface quality. Fused deposition…

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1300

Abstract

Purpose

The purpose of this paper is to study the integration between this technology and barrel finishing (BF) operation to improve part surface quality. Fused deposition modeling (FDM) processes have limitation in term of accuracy and surface finishing. Hence, post-processing operations are needed. A theoretical and experimental investigations have been carried out.

Design/methodology/approach

A geometrical model of the profile under the action of machining is proposed. The model takes into account FDM formulation and allows to predict the surface morphology achievable by BF. The MR needed in the model is obtained by a particular profilometer methodology, based on the alignment of Firestone–Abbot (F–A) curves. The experimental performed on a suitable geometry validated geometrical model. Profilometer and dimensional measurements have been used to assess the output of the coupled technologies in terms of surface roughness and accuracy.

Findings

The coupling of FDM and BF has been assessed and characterized in terms of obtained part surfaces and dimension evolution. Deposition angle strongly affects the BF removal speed and alters nominal dimensions of part. The geometric profile model gave interesting information about profile morphology and machining mechanism; moreover, the height prevision allows to estimate BF working time to accomplish part requirements.

Research limitations/implications

The prediction of the geometric profile as a function of FDM fabrication parameters is a powerful tool which permits to investigate surface properties such as mechanical coupling or tribological aspects. The coupling of BF and FDM has been assessed and now optimization of this process can be performed just evaluating effects of parameters.

Practical implications

This research has been focused to an industrial application, and results can be used in a computer-aided manufacturing. The prevision of surface obtainable by this integration is a tool to find the part optimum orientation to accomplish the drawing requirements. Both the experimental findings and the model can guide operator toward a proper process improvement, thus reducing or eliminating expensive trial and error phase in the post-processing operation of FDM prototypes.

Originality/value

In this paper, a novel model has been presented. It allows to know in advance profile morphology achievable by a specific surface of a FDM part after a determined BF working time. A particular application of FA curves gives the MR values.

Details

Rapid Prototyping Journal, vol. 21 no. 6
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 10 April 2017

Kankan Ji, Xingquan Zhang, Shubao Yang, Liping Shi, Shiyi Wang and Yuguo Wu

The purpose of this paper is to evaluate surface integrity of quenched steel 1045 ground drily by the brazed cubic boron nitride (CBN) grinding wheel and the black SiC…

Abstract

Purpose

The purpose of this paper is to evaluate surface integrity of quenched steel 1045 ground drily by the brazed cubic boron nitride (CBN) grinding wheel and the black SiC wheel, respectively. Surface integrity, including surface roughness, sub-surface hardness, residual stresses and surface morphology, was investigated in detail, and the surface quality of samples ground by two grinding wheels was compared.

Design/methodology/approach

In the present work, surface integrity of quenched steel 1045 machined by the CBN grinding wheel and the SiC wheel was investigated systematically. All the specimens were machined with a single pass in the down-cutting mode of dry condition. Surface morphology of the ground specimen was observed by using OLYMPUS BX51M optical microscopy. Surface roughness of seven points was measured by using a surface roughness tester at a cut-off length of 1.8 mm and the measurement traces were perpendicular to the grinding direction. Sub-surface micro-hardness was measured by using HVS-1000 digital micro-hardness tester after the cross-section surface was polished. The residual stress was tested by using X-350A X-ray stress analyzer.

Findings

When the cut depth is increased from 0.01 to 0.07 mm, the steel surface machined by the CBN wheel remains clear grinding mark, lower roughness, higher micro-hardness and higher magnitude of compressive stress and fine microstructure, while the surface machined by the SiC grinding wheel becomes worse with increasing of cut depth. The value of micro-hardness decreases, and the surface roughness increases, and the surface compressive stress turns into tensile stress. Some micro-cracks and voids occur when the sample is processed by the SiC grinding wheel with cut depth 0.07 mm.

Originality/value

In this paper, the specimens of quenched steel 1045 were machined by the CBN grinding wheel and the SiC wheel with various cutting depths. The processing quality resulted from the CBN grinding wheel is better than that resulted from the SiC grinding wheel.

Details

International Journal of Structural Integrity, vol. 8 no. 2
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 26 August 2014

Fei-Jun Chen, Shi Yan and Zhen-Guo Yang

The purpose of this study is to address two kinds of printed circuit board (PCB) failures with electrolytic Ni/Au as the surface finish. One was the weak bondability of…

Abstract

Purpose

The purpose of this study is to address two kinds of printed circuit board (PCB) failures with electrolytic Ni/Au as the surface finish. One was the weak bondability of gold wires to Ni/Au pads and the other was “dull gold” and weak solder wettability, which both caused great loss for the PCB manufacturer.

Design/methodology/approach

The failure samples were studied and analyzed in terms of macro- and micro-morphology of the surface finish, its element composition and thickness by various characterization techniques, such as three-dimensional stereo microscope, scanning electron microscope, energy dispersive spectroscopy and X-ray fluorescence spectrum.

Findings

Then the causes of the two failures were both found to be the inadequate thickness of gold deposit and other surface finish defects, but these causes played different roles in either failure or the mechanisms differ. Finally, their failure mechanisms were discussed and corresponding countermeasures were put forward for prevention.

Practical implications

This study not only addresses a practical failure problem but also provides some clues to a better and further understanding of the effect of PCB process and management on its quality and reliability in manufacturing practice.

Originality/value

It sheds light on how the thickness and quality of surface finish affects its wire bonding and soldering performances.

Details

Soldering & Surface Mount Technology, vol. 26 no. 4
Type: Research Article
ISSN: 0954-0911

Keywords

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