David J. Whitehouse

The Properties of Random Surfaces of Significance in their Contact

In recent work it has been shown that many types of surfaces used in engineering practice have a random structure. The paper takes, as a representation of the profile of such a surface, the waveform of a random signal; this is completely defined by two parameters, a height distribution and an auto-correlation function. It is shown how such a representation can be transformed into a model, appropriate for the study of surface contact, consisting of an array of asperities having a statistical distribution of both heights and curvatures. This theory is compared with the results of an analysis of surface profiles presented in digital form. The significance of these findings for the theory of surface contact and for the measurement and characterization of surface finish is discussed.

Some theoretical aspects of error separation techniques in surface metrology

There is an increasing demand for more accurate surface metrology instruments and for techniques which will allow complicated or large parts to be measured in situ. An analysis is presented of existing and new multi-orientation and multiprobe techniques and it is shown how they can be used to remove systematic and variable errors.

Handbook of surface and nanometrology

Introduction-Surface and Nanometrology General Surface Metrology Background to Surface Metrology Nanometrology Book Structure Characterization The Nature of Surfaces Surface Geometry Assessment and Parameters Characterization Waviness Errors of Form Characterization of Structured and Free Form Surfaces Characterization of Defects on the Surface Discussion Processing, Operations, and Simulations Digital Methods Discrete (Digital) Properties of Random Surfaces Digital Form of Statistical Analysis Parameters Digital Estimation of References for Surface Metrology Algorithms and Mathematical Techniques Basic Concepts in Linear Programming Fourier Transforms and the Fast Fourier Transform Transformations in Surface Metrology Space-Frequency Functions Surface Generation Atomistic Considerations and Simulations Summary Measurement Techniques Background Measurement Systems Stylus-Micro Measuring Instruments Stylus-Nano/Atomic Scale Optical Techniques Capacitance and Other Techniques Electron Microscopy, Photon Microscopy, Raman Spectrometry Comparison of Techniques-General Summary Some Design Considerations Standardization-Traceability-Uncertainty Introduction Nature of Errors Basic Error Theory Propagation of Errors Statistical Tests for Surface Metrology Uncertainty in Instruments-Calibration in General The Calibration of Stylus and Other Instruments Calibration of Form Instruments Variability of Surface Parameters Gps System-International and National Standards Specification for CAD and on Drawings Summary Surfaces and Manufacture Introduction Manufacturing Processes Cutting Abrasive Processes Unconventional Processes Forming Processes Effect of Scale of Size in Manufacture: Macro to Nano to Atomic Processes Structured Surface Manufacture Manufacture of Free-Form Surfaces Mathematical Processing of Manufacture-Finite Element Analysis (Fe), Md, Nurbs The Subsurface and the Interface Surface Integrity Surface Geometry-A Fingerprint of Manufacture Surface Finish Effects in Manufacture of Microchip Electronic Components Discussion and Conclusions Surface Geometry and Its Importance in Function Introduction Two-Body Interaction-The Static Situation Macro to Nanoscale, Contact, Adhesion Corrosion Two-Body Interactions-Dynamic Behavior Macro to Nanoscale, Friction, Wear, Lubrication One-Body Interactions- Optical Scatter, Diffraction System Function Multi-Surfaces Assembly Discussion Conclusions Surface Geometry, Scale of Size Effects, Nanometrology Introduction Effect of Scale of Size on Surface Geometry Scale of Size, Surface Geometry, and Function Scale of Size and Surfaces in Manufacture Nano Instrumentation Operation and Design Considerations Standards, Traceability, and Uncertainty at the Nanoscale Measurement of Typical Nanofeatures Measuring Length to Nanoscale with Interferometers and Other Devices Nano Geometry in Macro Situations Discussion and Conclusions General Comments Introduction Characterization Processing, Operations, and Simulations Measurement Techniques Traceability Standardization Uncertainty Surfaces and Manufacture Surface Geometry and Performance Nanometrology Overview Glossary Index References appear at the end of each chapter.

Paradigm shifts in surface metrology. Part II. The current shift

This is the second part of the paper ‘Paradigm shifts in surface metrology’. In part I, the three historical paradigm shifts in surface metrology were brought together, and the subsequent evolution resulting from the shifts discussed. The historical philosophy highlighted the fact that the paradigm shifts must be robust and flexible, meaning that surface metrology must allow for full control of surface manufacture and provide an understanding of the surface functional performance. Part II presents the current paradigm shift as a ‘stepping stone’, building on the above historical context. Aspects of surface geometry will also have to cater for surfaces derived from disruptive application, i.e. structured and freeform surfaces are identified candidates. The current shift is presented in three aspects: from profile to areal characterization; from stochastic to structured surfaces; and from simple geometries to complex freeform geometries, all spanning the millimetre to sub-nanometre scales. In this paradigm shift, the scale of surface texture is beginning to approach some of the geometrical features in micro/nano electro-mechanical systems devices and is becoming one of the most important functionality indicators. Part II will contextualize the current shifts in the discipline of surface metrology, and cement surface metrology in place in the ultra precision and nanotechnology age.

Stiffness estimation of a tripod-based parallel kinematic machine

This paper presents a simple yet comprehensive approach that enables the stiffness of a tripod-based parallel kinematic machine to be quickly estimated. The approach can be implemented by two steps. In the first step, the machine structure is decomposed into two substructures associated with the machine frame and the parallel mechanism. The stiffness model of each substructure is formulated by assuming that the components in the other substructure are rigid. This is followed by the second step that enables the stiffness model of the machine structure to be achieved by linear superposition. A 3D representation of the stiffness distributions within the usable workspace are depicted with comparison to those obtained through the finite element analysis.

The parameter rash — is there a cure?

Abstract In recent years there has been a proliferation of parameters with which to specify surface texture. Some of these parameters are useful, but most are not. The result of this rash is confusion and expense. In this paper the cause of the growth of such parameters is identified and ways of minimizing it are explored.

Characterization of Surface Texture Generated by Plateau Honing Process

The plateau honing operation is being widely used for finishing of cylinder liners for internal combustion engines. Plateau honing has been shown to significantly reduce the costly running-in period due to the fact that very little further modification of the texture is required once the liner is put into operation. In order to better understand, control, and ultimately “engineer” plateau honed surfaces, a comprehensive means of characterizing this texture is required. In this paper the techniques currently used are briefly reviewed and an alternate approach is proposed. The proposed approach is based on analyzing the cumulative distribution plot on a normal probability graph.

Paradigm shifts in surface metrology. Part I. Historical philosophy

Surface texture and its measurement are becoming the most critical factors and important functionality indicators in the performance of high precision and nanoscale devices and components. Surface metrology as a discipline is currently undergoing a huge paradigm shift: from profile to areal characterization, from stochastic to structured surfaces, and from simple geometries to complex free-form geometries, all spanning the millimetre to sub-nanometre scales. This paper builds a complete philosophical framework for surface metrology through a review of the paradigm shifts that have occurred in the discipline of surface metrology, tracing the development of fundamental philosophies and techniques. The paper starts with a brief overview of the historical paradigm shifts and builds an up-to-date foundational philosophy, capable of rapid and effective development. The growth in interest in surface metrology stems mainly from the need to control the manufacture of armaments during the Second World War and the production of domestic goods and appliances since that time. The surfaces produced by manufacture seemed to offer the possibility of being useful for process control. Unfortunately, only a few tentative investigations had been carried out to establish usable relationships between the processes, the machine tools and the available surface parameters (with their limitations). Even fewer investigations had been carried out to relate surface geometry to the performance of manufactured products. The result was that the metrology was unprepared and, consequently, the progress was sporadic. This overall review is given in two parts. Part I focuses on the historical philosophy of surface metrology and Part II discusses the progress within the current paradigm shift.

The Local Dexterity, Optimal Architecture and Design Criteria of Parallel Machine Tools

Abstract In this paper, the analytical expressions of the local dexterity loci of parallel machine tools described by the singular values of the Jacobian matrix are formulated. It has been proved that the different kinematic performance indexes to evaluate the dexterity of the machine tools are inherently identical. The parametric relationship to obtain isotropy configurations is derived. By introducing the concept of relative dexterity, the design criteria in conjunction with the detailed procedure are proposed according to the specific requirements. It has been concluded via examples that if the dimensional parameters are designed in such a way that the local kinematic performance is satisfactory, so is the global performance provided that the reachable orientation of the mobile platform is limited due to the constraints of the passive joints and actuated variables.

Fractal or fiction

Fractal properties of surfaces have been explored by many investigators. Most have concluded that fractal characterisation is useful. This note questions the philosophy of using fractals to describe and control engineering surfaces. It concludes that the benefits are more virtual than real. The functional significance of fractal parameters is also examined and the overall question arises as to whether scale invariant parameters are appropriate.