David Lee Butler

The characterisation of grinding wheels using 3D surface measurement techniques

Abstract Surface measurement using 3D stylus instruments is a relatively new technique which offers numerous advantages over the more common profilometry methods. The information generated is, unlike profile measurements, less subjective and more statistically relevant providing additional insight regarding the surface structure. One application of surface measurement which has encountered problems when using the profilometry method is that of grinding wheel characterisation. The wheel surface texture (topography) and the conditions under which it is generated have a profound effect upon the grinding performance as characterised by the grinding forces, power consumption, temperature, and surface integrity of components. A detailed knowledge of the nature of the topography of the grinding wheel would provide further insight into the surface interaction of the grinding wheel as well as enabling improved control of the grinding process in general. Through the employment of novel 3D surface descriptors, this paper will investigate the topographic change which occurs on both the wheel and workpiece and attempt to relate this to force data and scanning electron microscopy. The results will demonstrate that this topographic characterisation technique correlates well with more accepted methods.

Fabrication of a micro-size diamond tool using a focused ion beam

An investigation on the feasibility of sputtering a diamond block into a specially designed three-dimensional cutting tool shape using a focused ion beam (FIB) was carried out. The ion-sputtered removal rate, surface morphology and sputtered feature accuracy were evaluated with respect to the FIB parameters such as ion current and angle of ion incidence through sputtering pockets on the top surface of a diamond substrate. A single crystalline diamond tool, with 25 µm length in the cutting edge and smooth face quality, has been successfully fabricated by using a FIB. These excellent tool characteristics are proven in the results obtained from the machining experiments done on the ultra-precision machine.

Topographic features of cylinder liners — an application of three-dimensional characterization techniques

Studies of wear patterns on engine cylinder liners show that radial wear is greatest on the anti-thrust side, and close to top dead centre. As a result of this wear, surface topography features at different positions exhibit different characteristics. Quantitative representation of the features is helpful for functional analysis and functional control of cylinder liner manufacture. In this paper three-dimensional characterization techniques are applied to produce a comprehensive characterization of cylinder liner wear at different longitudinal positions. The areal autocorrelation function and the areal power spectrum reveal the changes in topographic features. The different topographic features of newly created, after running-in, severely worn and bore polished surfaces of cylinder liners are identified by quantitative functional indices. The characterization techniques and parameters used in the paper constitute an effective approach to the characterization of surface topography of cylinder liners and other tribological surfaces.

Operational implications of early supplier involvement in semiconductor manufacturing firms: A case study

Purpose – Existing earlier supplier involvement (ESI) models mostly emphasize the product development perspective with limited attention to the process development dimension. Towards this end, this paper aims at a tailored framework for semiconductor manufacturing firms by taking into account the implementation of ESI in process development as well as product development.Design/methodology/approach – A number of well‐recognized propositions are examined through a case study of MIC Semiconductors Asia. Based on observations from the case study, the problems of existing frameworks are analyzed and accordingly possible solutions are explored.Findings – The case study reveals the importance of process development in ESI implementation. It is imperative to build up on some fundamentals of the company before ESI can be carried out successfully. Also observed is that the effectiveness of a supplier selection criterion should be gauged from the performance of the suppliers. It is also found out what type of relat...

The effects of hard particles on the surface quality when micro-cutting aluminum 6061 T6

Studies of micro-cutting have so far largely been carried out on single-phase materials. Due to the size effect, the workpiece material microstructure can have a significant influence on the cutting force, chip formation and surface quality. Previous investigations have shown that hard particles in materials such as aluminum alloy can play a significant role in the generation of defects such as cracks and voids on the work surface. This paper will examine the extent of the problem during the micro-cutting of Al6061 T6 and propose how it can be mitigated.

Correlation-length-based sampling conditions for various engineering surfaces

The paper proposes the criteria for selecting the sampling condition in three-dimensional surface measurement. The criteria are based on the fact that there is a relationship between the correlation length of the measured surface and its high-frequency cut-off. Through the use of the sampled surfaces and the analytical models, it is shown that the criteria are equivalent to the power spectral analysis.

Compositional depth profile analysis of coatings on hard disks by X-ray photoelectron spectroscopy and imaging

A hard disk medium is typically composed of several layers including the magnetic recording layer, a buffer layer, as well as a wear protective layer. In the work presented here, the hard disks analysed have a total of five layers with the uppermost layer being the lubricant. The second layer is diamond like coating and this is followed by the magnetic layer consisting of an alloy of cobalt and other elements. The fourth layer is a buffer composed of an alloy of chromium, vanadium and molybdenum with the final layer being a nickel transition layer doped with phosphorus. These multilayers were subjected to numerous etchings by argon ions. The chemical structures of these layers were analysed with an X-ray photoelectron spectroscope (XPS) after each etching. Combining the XPS spectra with XPS imaging it is possible to determine the depth distribution of elements in the hard disk coating. In addition, it is also shown that XPS imaging can be employed to monitor the thickness of all multilayers.

New approach to estimate coverage parameter in 3D FEM shot peening simulation

ABSTRACT Shot peening is a surface cold working process used to enhance the fatigue life of metallic parts or members. Coverage is a major parameter of shot peening process, which is defined as the percentage of the sum of peened area over the total area on the surface of the specimen. In this paper, a new method is proposed to estimate the full coverage for simulation of the shot peening process. A dynamic plastic model of the shot peening process with the aid of MatlabTM code is also presented using the finite element method (FEM). The numerical results show that the coverage, shot velocity and radius significantly affect the residual stress distribution of the target material, AISI 4340 steel. In addition, a double-shot peening process is also studied in simulation to consider its effect on compressive residual stress distribution.

Mechanical and Tribological Properties of Shot-Peened SAE 1070 Steel

ABSTRACT The effects of shot peening pressure on the mechanical and tribological properties of shot-peened SAE 1070 steel strips were systematically investigated. The surface hardness of the shot-peened steel strips significantly increased with increased shot peening pressure due to the promoted cold work-hardening effect. The tribological results showed that the increased surface roughness of the shot-peened steel strips associated with increased shot peening pressure resulted in their increased friction by enhancing mechanical interlocking between two rubbing surfaces. The wear of the shot-peened steel strips decreased with increased shot peening pressure via their increased surface hardness. However, the shot-peened steel strips at shot peening pressures less than 345 kPa did not exhibit better wear resistance than the as-received steel strip, indicating that a certain intensity of shot peening was required to improve the wear resistance of the shot-peened steel strips. It could be concluded that the mechanical and tribological properties of the shot-peened steel strips were significantly influenced by the shot peening pressure.

Effects of shot peening pressure, media type and double shot peening on the microstructure, mechanical and tribological properties of low-alloy steel

The effects of different shot peening conditions such as pressure (from 68.9–551.6 kPa), media type (media S230 and S110) and double shot peening on the microstructure, mechanical and tribological properties of shot peened AISI 4340 low-alloy steels, were systematically investigated. Their surface topography, hardness and roughness were analyzed by scanning electron microscopy, a Vickers micro-hardness tester and surface profilometer, respectively, while the cross-sectional sub-surface structures of the as-received and shot peened samples were characterized by means of optical microscopy and nanoindentation. The tribological properties were determined by using a ball-on-disc micro-tribological tester. It was shown that shot peening pressure and media type had a significant effect on the surface roughness, hardness, microstructure, wear resistance and friction of the shot peened AISI 4340 steel samples. It also indicated that the double shot peening process was a promising treatment, not only to reduce the surface roughness of the material after undergoing the first shot peening process with large media and high intensity, but to improve the tribological properties of the shot peened material.