Search results

1 – 10 of over 5000
To view the access options for this content please click here
Article
Publication date: 2 September 2014

De-Xing Peng

The purpose of this paper is to investigate the effects of abrasive contents, oxidizer contents, slurry flow rate and polishing time in achieving a mirror-like finish on…

Abstract

Purpose

The purpose of this paper is to investigate the effects of abrasive contents, oxidizer contents, slurry flow rate and polishing time in achieving a mirror-like finish on polished surfaces. Chemical mechanical polishing (CMP) is now widely used in the aerospace industry for global planarization of large, high value-added components.

Design/methodology/approach

Optimal parameters are applied in experimental trials performed to investigate the effects of abrasive contents, oxidizer contents, slurry flow rate and polishing time in achieving a mirror-like finish on polished surfaces. Taguchi design experiments are performed to optimize the parameters of CMP performed in steel specimens.

Findings

Their optimization parameters were found out; the surface scratch, polishing fog and remaining particles were reduced; and the flatness of the steel substrate was guaranteed. The average roughness (Ra) of the surface was reduced to 6.7 nm under the following process parameters: abrasive content of 2 weight per cent, oxidizer content of 2 weight per cent, slurry flow rate of 100 ml/min and polishing time of 20 min.

Originality/value

To meet the final process requirements, the CMP process must provide a good planarity, precise selectivity and a defect-free surface. Surface planarization of components used to fabricate aerospace devices is achieved by CMP process, which enables global planarization by combining chemical and mechanical interactions.

Details

Industrial Lubrication and Tribology, vol. 66 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

To view the access options for this content please click here
Article
Publication date: 18 January 2016

Mengqi Yuan and David Bourell

The purpose of this paper is to improve the quality of additive manufactured optically translucent parts by investigating the manufacturing issues, analyzing lithophane…

Abstract

Purpose

The purpose of this paper is to improve the quality of additive manufactured optically translucent parts by investigating the manufacturing issues, analyzing lithophane production criteria and identifying the best translucent material and additive manufacturing (AM) technology.

Design/methodology/approach

Figured lithophanes were laser sintered on a 3D Systems SinterStation® HiQ™ with varying layer thickness and plate thickness. Laser sintered (LS) polyamide (PA) 12 blanks were cyanoacrylate infiltrated and polished. Optical properties and performance were compared with the original LS blanks. Lithophanes and blanks were manufactured using 3D systems stereo lithography apparatus (SLA)® Viper ™si2 station, and optical properties and lithophane performance were compared with the LS specimens.

Findings

When building in the XY plane, it is optimal to sinter with the minimum layer thickness (0.076 mm) and maximum plate thickness (5 mm). Cyanoacrylate infiltration and polishing assists in reducing the LS PA 12 plate surface roughness, but polishing does not affect the lithophane performance. The best LS candidate should have an absorption coefficient of 0.5/mm using a white light source. Improved resolution but reduced contrast was observed on stereolithography (SL) specimens compared to LS parts.

Research limitations/implications

Transmittance experiments were performed on three SL parts which was not sufficient for optical property calculation. Limited literature was found for new material exploration.

Originality/value

It is the first effort to study systematically quality improvement issues of LS PA optically translucent parts. A comparison is made of optical performance between parts made using LS and SL.

Details

Rapid Prototyping Journal, vol. 22 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 8 January 2018

Yun He, Fanghong Sun and Xuelin Lei

This study aims to obtain diamond-coated mechanical seals with improved sealing performance and considerable cost. To achieve this purpose, the study focuses on depositing…

Abstract

Purpose

This study aims to obtain diamond-coated mechanical seals with improved sealing performance and considerable cost. To achieve this purpose, the study focuses on depositing uniform, wear-resistant and easily polished diamond coatings on massive mechanical seals in a large-scale vacuum chamber.

Design/methodology/approach

The computational fluid dynamics simulation test and its corresponding deposition experiment are carried out to improve the uniformity of diamond films on massive mechanical seals. The polishing properties and sealing performance of mechanical seals coated with three different diamond films (microcrystalline diamond [MCD], nanocrystalline diamond [NCD] and microcrystalline/nanocrystalline diamond [MNCD]) and uncoated mechanical seals are comparatively studied using the polishing tests and dynamic seal tests to obtain the optimized diamond coating type on the mechanical seals.

Findings

The substrate rotation and four gas outlets distribution are helpful for depositing uniform diamond coatings on massive mechanical seals. The MNCD-coated mechanical seal shows the advantages of high polishing efficiency in the initial polishing process and excellent wear resistance and self-lubrication property in the follow-up polishing period because of its unique composite diamond film structures. The MNCD-coated mechanical seal shows the longest working life under dry friction condition, about 14, 1.27 and 1.9 times of that for the uncoated, MCD and NCD coated mechanical seals, respectively.

Originality/value

The effect of substrate rotation and gas outlets distribution on temperature and gas flow field during diamond deposition procedure is simulated. The MNCD-coated mechanical seal exhibits a superior sealing performance compared with the MCD-coated, NCD-coated and uncoated mechanical seals, which is helpful for decreasing the operating system shut-down frequency and saving operating energy consumption.

Details

Industrial Lubrication and Tribology, vol. 70 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

To view the access options for this content please click here
Article
Publication date: 4 February 2014

De-Xing Peng

Chemical mechanical polishing (CMP) has attracted much attention recently because of its importance as a nano-scale finishing process for high value-added large components…

Abstract

Purpose

Chemical mechanical polishing (CMP) has attracted much attention recently because of its importance as a nano-scale finishing process for high value-added large components that are used in the aerospace industry. The paper aims to discuss these issues.

Design/methodology/approach

The characteristics of aluminum nanoparticles slurry including oxidizer, oxidizer contents, abrasive contents, slurry flow rate, and polishing time on aluminum nanoparticles CMP performance, including material removal amount and surface morphology were studied.

Findings

Experimental results indicate that the CMP performance depends strongly on the oxidizer, oxidizer contents, and abrasive contents. Surface polished by slurries that contain nano-Al abrasives had a lower surface average roughness (Ra), lower topographical variations and less scratching. The material removal amount and the Ra were 124 and 7.61 nm with appropriate values of the process parameters of the oxidizer, oxidizer content, abrasive content, slurry flow rate and polishing time which were H2O2, 2 wt.%, 1 wt.%, 10 ml/min, 5 min, respectively.

Originality/value

Based on SEM determinations of the process parameters for the polishing of the surfaces, the CMP mechanism was deduced preliminarily.

Details

Industrial Lubrication and Tribology, vol. 66 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

To view the access options for this content please click here
Article
Publication date: 1 March 1994

A.A. Taha, S.A. Sallam and A.M. Ahmed

Introduction Much work has been done on the phenomenon of electropolishing since it was discovered by Jaquat. Most of this work was directed towards the elucidation of the…

Abstract

Introduction Much work has been done on the phenomenon of electropolishing since it was discovered by Jaquat. Most of this work was directed towards the elucidation of the polishing mechanism as well as establishing conditions for polishing of different metals and alloys. Studies on the polishing mechanism have revealed that electropolishing is a diffusion‐controlled process, which takes place at the limiting current, and electropolishing can therefore be treated quantitatively using the theory of mass transfer to the cathodic deposition of metal and metal powder. Some work has been done on the study of electropolishing under forced convection mass transfer conditions. A notable recent investigation involving copper and copper‐based alloys in a stirred cell is due to the study of Gabe and strongly suggests a diffusion‐limited mechanism at low temperature. Fouad et al. studied mass transfer under free convection in the electropolishing of vertical copper electrodes in phosphoric acid.

Details

Anti-Corrosion Methods and Materials, vol. 41 no. 3
Type: Research Article
ISSN: 0003-5599

To view the access options for this content please click here
Article
Publication date: 20 November 2020

S. Madhu and M. Balasubramanian

The purpose of this study is for solving many issues in production that includes processing of complex-shaped profile, machining of high-strength materials, good surface…

Abstract

Purpose

The purpose of this study is for solving many issues in production that includes processing of complex-shaped profile, machining of high-strength materials, good surface finish with high-level precision and minimization of waste. Among the various advanced machining processes, abrasive jet machining (AJM) is one of the non-traditional machining techniques used for various applications such as polishing, deburring and hole making. Hence, an overview of the investigations done on carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GRFP) composites becomes important.

Design/methodology/approach

Discussion on various approaches to AJM, the effect of process parameters on the glass fiber and carbon fiber polymeric composites are presented. Kerf characteristics, surface roughness and various nozzle design were also discussed.

Findings

It was observed that abrasive jet pressure, stand-off distance, traverse rate, abrasive size, nozzle diameter, angle of attack are the significant process parameters which affect the machining time, material removal rate, top kerf, bottom kerf and kerf angle. When the particle size is maximum, the increased kinetic energy of the particle improves the penetration depth on the CFRP surface. As the abrasive jet pressure is increased, the cutting process is enabled without severe jet deflection which in turn minimizes the waviness pattern, resulting in a decrease of the surface roughness.

Research limitations/implications

The review is limited to glass fiber and carbon fiber polymeric composites.

Practical implications

In many applications, the use of composite has gained wide acceptance. Hence, machining of the composite need for the study also has gained wide acceptance.

Social implications

The usage of composites reduces the usage of very costly materials of high density. The cost of the material also comes down.

Originality/value

This paper is a comprehensive review of machining composite with abrasive jet. The paper covers in detail about machining of only GFRP and CFRP composites with various nozzle designs, unlike many studies which has focused widely on general AJM of various materials.

Details

World Journal of Engineering, vol. 18 no. 2
Type: Research Article
ISSN: 1708-5284

Keywords

To view the access options for this content please click here
Article
Publication date: 1 March 2013

Frank Alifui‐Segbaya, Paul Foley and R.J. Williams

Rapid manufacture‐produced cobalt chromium alloys are beginning to be used in dentistry but there are few published results relating to their properties. The purpose of…

Abstract

Purpose

Rapid manufacture‐produced cobalt chromium alloys are beginning to be used in dentistry but there are few published results relating to their properties. The purpose of this paper is to determine the corrosion resistance of a rapid manufacture‐produced dental alloy and compare it to a standard dental casting alloy.

Design/methodology/approach

In accordance with ISO 22674, ten samples of each alloy were fabricated in approximately 45 mm×10 mm×2 mm rectangular prisms, a sample number in excess of the standard requirements. The groups were further divided into those with highly polished surfaces and those with electrobrightened surfaces. Each sample was immersed in artificial saliva, suspended by a nylon thread for 42 days at 37°C. Readings for cobalt, chromium and molybdenum ions released into solutions were obtained using an atomic absorption spectrometer at 1, 4, 7, 14, 21, 28, 35, and 42 day intervals at a detection limit of one part per million.

Findings

Ion release of cobalt, chromium and molybdenum was well within the threshold prescribed by the standard. The alloys were safe for use as dental devices with respect to the above metals. The rapid manufacture alloy however performed better. In addition the data indicated that for both alloys, there was no discernable difference between a polished and an electrobrightened surface.

Originality/value

The rapid manufacture alloy studied shows a safe level of corrosion resistance with respect to cobalt, chromium and molybdenum according to ISO definitions. Further biocompatibility tests are recommended.

Details

Rapid Prototyping Journal, vol. 19 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 15 June 2010

Takako Inoue, Kengo Ishihara, Kyoden Yasumoto and Masako Niwa

The purpose of this paper is to examine ladies' linen fabrics produced in different regions – Japan, Italy, and Poland – to ascertain differences in mechanical, thermal…

Abstract

Purpose

The purpose of this paper is to examine ladies' linen fabrics produced in different regions – Japan, Italy, and Poland – to ascertain differences in mechanical, thermal, and air permeability properties.

Design/methodology/approach

The paper investigates mechanical properties, air permeability, and thermal conductivity. The silhouettes of Polish, Italian, and Japanese linen fabrics are different. The thermal conductivities of the Polish linen fabrics are high. The levels of 72 elements were analyzed and remarkable differences were observed in the levels of 16 elements, including Li, Al, Si, Ti, Cr, Ni, Rb, and Y, Ag, among Polish, Italian linen fabrics, and linen fabrics made in Japan. Another ten elements were detected at some level in either the samples of Polish linen fabrics or linen fabrics made in Japan.

Findings

There are differences among the Polish, Italian, and linen fabrics made in Japan, but the differences are not remarkable.

Research limitations/implications

This paper is a wide world regional study of linen characterisation.

Practical implications

Another ten elements are detected at some level in either the samples of Polish linen fabrics or linen fabrics made in Japan. There are differences among the Polish, Italian, and linen fabrics made in Japan, but the differences are not remarkable.

Originality/value

The paper presents useful Measurement instrumentation, analysis and characterisation of linen fabrics from different regions of the world.

Details

International Journal of Clothing Science and Technology, vol. 22 no. 2/3
Type: Research Article
ISSN: 0955-6222

Keywords

To view the access options for this content please click here
Article
Publication date: 1 August 2000

S. Kawabata, Masako Niwa, R. Koztowsky, S. Manys, K. Nakano and Takako Inoue

Recently, the Polish National Fiber Research Laboratory provided linen samples. In addition to these Polish fabric samples, we also collected linen fabric samples which…

Abstract

Recently, the Polish National Fiber Research Laboratory provided linen samples. In addition to these Polish fabric samples, we also collected linen fabric samples which were made in Japan and throughout Europe. We have investigated hand properties of various linen fabrics, and identification of the Polish linen fabrics quality from those of other linen fabrics. The fabric hand of Polish linen fabrics is unique, it possesses a hand just between wool‐like and cotton‐like fabrics. We have clarified that the Polish linen fabrics are suitable for hari‐type and tailored type silhouette designs for women’s wear, and the fabrics are well‐suited for finishing garment appearance.

Details

International Journal of Clothing Science and Technology, vol. 12 no. 3
Type: Research Article
ISSN: 0955-6222

Keywords

To view the access options for this content please click here
Article
Publication date: 16 April 2018

Hanna Augustyniak, Jacek Laszek, Krzysztof Olszewski and Joanna Waszczuk

The purpose of this paper is to describe the property valuation methods that are applied in Poland. It shows that they base on international standards and are a reliable…

Abstract

Purpose

The purpose of this paper is to describe the property valuation methods that are applied in Poland. It shows that they base on international standards and are a reliable source of information for international investors and banks.

Design/methodology/approach

The valuation methods are described and critically assessed, potential problems are pointed out. The analysis of lending risk is analysed on data about non-performing loans (NPL).

Findings

Polish valuation methods are in line with international methods, but there are some risks, like small number of transactions, subjective behaviour of valuers. The low NPL ratios indicate that the valuation works correctly.

Practical implications

The Polish valuation methods are trustworthy, non-performing mortgage ratios are low, however, banks and investors should ask whether there is a local zoning plan. Moreover, they should look critically at the comparables that were used during the valuation process, if in their opinion the valuation is overly low or high.

Originality/value

This paper focusses on valuation from a financial stability perspective. It uses Polish literature and data on NPLs to give an insight on valuation of property and mortgage risk in Poland. Besides the review of the methods it points out the problems related to valuation uncertainty, such as the risk of subjective behaviour of valuers and the low number of transactions in some regions, which are used for valuations.

Details

Property Management, vol. 36 no. 2
Type: Research Article
ISSN: 0263-7472

Keywords

1 – 10 of over 5000