Simon Fletcher

Simon Fletcher
University of Huddersfield · Centre for Precision Technologies

PhD FHEA

About

104
Publications
39,283
Reads
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1,019
Citations
Citations since 2016
32 Research Items
832 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
Additional affiliations
September 2001 - September 2014
University of Huddersfield
Position
  • Senior Researcher
Description
  • Working on Machine tool performance related projects such as FP7 projects (ADAMOD, HARCO, SOMMACT, EASE-R3) and industrial projects such as SAMULET and various consultancy work.
Education
September 1991 - July 1995
University of Huddersfield
Field of study
  • Computer Aided Engineering

Publications

Publications (104)
Article
The recent development of low-cost accelerometers, driven by the Industrial Internet of Things (IIoT) revolution, provides an opportunity for their application in precision manufacturing. Sensor data is often of the highest consideration in any precision machining process. While high-cost vibration sensors have traditionally been employed for vibra...
Chapter
Full-text available
This paper investigates the use of the discrete wavelet transform (DWT) and Fast Fourier Transform (FFT) to improve the quality of extracted features for machine learning. The case study in this paper is detecting the health state of the ballscrew of a gantry type machine tool. For the implementation of the algorithm for feature extraction, wavelet...
Article
Monitoring strain is important in precision engineering applications that require maintaining the precise alignments of structures over time, such as those found in machine tools and metrology frames. We present a fiber-optic strain measurement technique based upon broadband interferometry that is variously configurable in terms of gauge length and...
Article
Full-text available
Efficient photovoltaic installations require control systems that detect small signal variations over large measurement ranges. High measurement accuracy requires data acquisition systems with high-resolution analogue-to-digital converters; however, high resolutions and operational speeds generally increase costs. Research has proven low-cost proto...
Chapter
Condition monitoring systems generally require data acquisition (DAQ) systems. These in turn necessitate high-precision analogue-to-digital converters (ADCs) to sample and convert analogue signals from sensors into digital data, for establishing the condition of the monitored equipment. There is generally a need for high-accuracy measurement of min...
Article
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Industrial robots have been more and more involved in the automation industry due to their capability to perform precise tasks, with an accuracy in sub-millimeters, tasks such as welding and drilling where a successful cooperation between the robots and the machine vision is necessary to end tasks within a demanded accuracy and in less execution ti...
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Article History: Vision systems have now been involved to a greater extent in robotic manufacturing applications due to their non-contact features and high accuracy. The visual information extracted from the vision sensor significantly assists robot manipulators to perform a variety of tasks with an accuracy that satisfactorily meets the industrial...
Article
The current standard for machine tool calibration supports the use of quasi-static measurement techniques. When measuring the six degrees of freedom motion errors, the measurements are typically taken consecutively. This introduces uncertainty when comparing the results due to machine deformation during individual measurements. Furthermore, quasi-s...
Conference Paper
Core temperature variation in metals during manufacturing processes affects both the dimensional accuracy and the surface integrity of manufactured workpieces. Different types of temperature measurement techniques have been applied for obtaining workpiece temperature. However, their main limitations have been an inability to give the core temperatu...
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Temperature measurement is one of the most important aspects of manufacturing. There have been many temperature measuring techniques applied for obtaining workpiece temperature in different types of manufacturing processes. The main limitations of conventional sensors have been the inability to indicate the core temperature of workpieces and the lo...
Conference Paper
Temperature variation is one of the most important factors that affect the dimensional accuracy and surface integrity of workpieces during machining processes. Several attempts have been made towards estimating machine tool and workpiece temperature. The techniques used generally depend on the type of material and the level of accuracy required. Ho...
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Coordinate Measuring Machines (CMM) are widely used to validate the dimensional conformance of machined components. Since time frames are critical in ensuring cost effective production, it is important to know when a machined component is ready for dimensional inspection. A common approach is to delay the inspection until the component has reached...
Conference Paper
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The function of collimators in the Large Hadron Collider (LHC) is to control and safely dispose of the halo particles that are produced by unavoidable beam losses from the circulating beam. Even tiny proportions of the 7TeV beam have the stored energy to quench the superconducting magnets or damage parts of the accelerator if left unchecked. Partic...
Article
Full-text available
Purpose To produce a decision support aid for machine tool owners to utilise while deciding upon a maintenance strategy. Furthermore, the decision support tool is adaptive and capable of suggesting different strategies by monitoring for any change in machine tool manufacturing accuracy. Design/methodology/approach A maintenance cost estimation m...
Conference Paper
Knowledge of machine tool drive dynamics is imperative to achieve optimal, robust performance with precision and productivity. Modelling ball-screw drives is vital in order to have a feasible insight into the structural vibration modes of the mechanical assembly, which typically limits the bandwidth of developed controllers. In this paper, an outpu...
Article
Purpose: The purpose of this paper is to produce an intelligent technique for modelling machine tool errors caused by the thermal distortion of Computer Numerical Control (CNC) machine tools. A new metaheuristic method, the Cuckoo Search (CS) algorithm, based on the life of a bird family is proposed to optimize the GMC(1, N) coefficients. It is the...
Conference Paper
Full-text available
There has recently been an increased emphasis on reducing energy consumption in manufacturing, driven by the fluctuations in energy costs and the growing importance given to environmental impact of manufactured goods. Lots of attention has been given to the reduction of machine tools energy consumption, as they require large amounts of energy to pe...
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There has recently been an increased emphasis on reducing energy consumption in manufacturing, driven by the fluctuations in energy costs and the growing importance given to environmental impact of manufactured goods. Lots of attention has been given to the reduction of machine tools energy consumption, as they require large amounts of energy to pe...
Conference Paper
Full-text available
Over the last few years, various techniques and metrological instruments have been proposed to achieve accurate process control on the shop floor at low cost. An efficient solution that has been recently adopted for this complex task is to perform coordinate measurement in comparator mode in order to eliminate the influence of systematic effects as...
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Recent advances in versatile automated gauging have enabled accurate geometric tolerance assessment on the shop floor. This paper is concerned with the uncertainty evaluation associated with comparative coordinate measurement using the design of experiments (DOE) approach. It employs the Renishaw Equator which is a software-driven comparative gauge...
Conference Paper
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An essential part of assessing whether a measurement or gauging system meets its intended purpose is to estimate the measurement uncertainties. This paper employs the design of experiments (DOE) approach to implement a practical analysis of measurement uncertainty of Renishaw Equator automated flexible gauge. The factors of interest are measurement...
Book
The overall quality of a machined component has an important association with the quality of its surface finish. To obtain adequate data for the surface metrology of machined components, areal scanners are often preferred over stylus based profile scanners due to their ability to acquire surface data over a relatively large area. To further improve...
Conference Paper
The overall quality of a machined component has an important association with the quality of its surface finish. To obtain adequate data for the surface metrology of machined components, areal scanners are often preferred over stylus based profile scanners due to their ability to acquire surface data over a relatively large area. To further improve...
Article
Full-text available
The most compelling requirements for visual tracking systems are a high detection accuracy and an adequate processing speed. However, the combination between the two requirements in real world applications is very challenging due to the fact that more accurate tracking tasks often require longer processing times, while quicker responses for the tra...
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This paper presents a new modelling methodology for compensation of the thermal errors on a gantry-type 5-axis CNC machine tool. The method uses a “Grey Neural Network Model with Convolution Integral” (GNNMCI(1, N)), which makes full use of the similarities and complementarity between Grey system models and artificial neural networks (ANNs) to over...
Conference Paper
A new strategy for improving vision based tracking accuracy based on utilization of camera calibration information Original Citation Alzarok, Hamza, Fletcher, Simon and Longstaff, Andrew P. (2016) A new strategy for improving vision based tracking accuracy based on utilization of camera calibration information. Abstract— Camera calibration is one o...
Article
Full-text available
Machine tool calibration is becoming recognised as an important part of the manufacturing process. The current international standards for machine tool linear axes calibration support the use of quasi-static calibration techniques. These techniques can be time consuming but more importantly a compromise in quality due to the practical restriction o...
Conference Paper
Full-text available
Coordinate measuring machines (CMMs) are complex measuring systems that are widely used in manufacturing industry for form, size, position, and orientation assessment. In essence, these systems collect a set of individual data points that in practice is often a relatively small sample of an object. Their software then processes these points in orde...
Conference Paper
Full-text available
Traditional manufacturing uses coordinate measuring machines (CMMs) or component-specific gauging for in-process and post-process inspection. In assessing the fitness for purpose of these measuring systems, it is necessary to evaluate the uncertainty associated with CMM measurement. However, this is not straightforward since the measurement results...
Article
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This paper presents a robust displacement sensor with nanometre-scale resolution over a micrometre range. It is composed of low cost commercially available slotted photo-microsensors (SPMs). The displacement sensor is designed with a particular arrangement of a compact array of SPMs with specially designed shutter assembly and signal processing to...
Article
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Manufacturing industries strive to produce improved component accuracy while not reducing machine tool availability or production throughput. The accuracy of CNC production machines is one of the critical factors in determining the quality of these components. Maintaining the capability of the machine to produce intolerance parts can be approached...
Conference Paper
Full-text available
Many manufacturers aim to increase their levels of high-quality production in order to improve their market competitiveness. Continuous improvement of maintenance strategies is a key factor to be capable of delivering high quality products and services on-time with minimal operating costs. However, the cost of maintaining quality is often perceived...
Conference Paper
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Thermal errors can have a significant effect on CNC machine tool accuracy. The thermal error compensation system has become a cost-effective method of improving machine tool accuracy in recent years. In the presented paper, the Grey relational analysis (GRA) was employed to obtain the similarity degrees between fixed temperature sensors and the the...
Conference Paper
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Abstract Camera based systems have been a preferred choice in many motion tracking applications due to the ease of installation and the ability to work in unprepared environments. The concept of these systems is based on extracting image information (colour and shape properties) to detect the object location. However, the resolution of the image a...
Article
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Thermal errors can have significant effects on CNC machine tool accuracy. The errors come from thermal deformations of the machine elements caused by heat sources within the machine structure or from ambient temperature change. The effect of temperature can be reduced by error avoidance or numerical compensation. The performance of a thermal error...
Article
Full-text available
Thermal errors are often quoted as being the largest contributor to CNC machine tool errors, but they can be effectively reduced using error compensation. The performance of a thermal error compensation system depends on the accuracy and robustness of the thermal error model and the quality of the inputs to the model. The location of temperature me...
Conference Paper
Full-text available
The fast and accurate modelling of thermal errors in machining is an important aspect for the implementation of thermal error compensation. This paper presents a novel modelling approach for thermal error compensation on CNC machine tools. The method combines the Adaptive Neuro Fuzzy Inference System (ANFIS) and Grey system theory to predict therma...
Conference Paper
Full-text available
Manufacturing strives to reduce waste and increase Overall Equipment Effectiveness (OEE). When managing machine tool maintenance a manufacturer must apply an appropriate decision technique in order to reveal hidden costs associated with production losses, reduce equipment downtime competently and similarly identify the machines’ performance. Total...
Article
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The reduction of the lead time in measurement and reverse engineering, and the increased requirements in terms of accuracy and flexibility, have resulted in a great deal of research effort aimed at developing and implementing multi-sensor systems. This paper describes an effective competitive approach for using a tactile probe to compensate the dat...
Article
There is a requirement for improved 3D surface characterisation and reduced tool wear, when modern computer numerical-controlled (CNC) machine tools are operating at high cutting velocities, spindle speeds and feed-rates. This research project investigates vibration-induced errors on a CNC vertical machining centre under dynamic conditions. A model...
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This paper describes evaluation of a method of measuring the straightness of motion of machine tool axes using a taut wire and an optical sensor head mounted at the tool point location. In contrast to commonly used taut wire instruments, straightedges or laser-based methods, this solution combines low cost, simplicity of setup and automated data ca...
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This paper deals with the accuracy of compensation of machine tools using a tracking interferometer using the multilateration method. The measurement strategy and thermal drift compensation of the measurements are studied. It shows that most effects of temperature are accurately compensated by the laser tracking interferometer software. However, th...
Conference Paper
Full-text available
Minimising manufacturing waste and reducing downtime are becoming increasingly important to industrial companies, especially those manufacturing with high levels of output or to a high level of accuracy, such as mobile phone, submarine, and aircraft. Increasingly, predictable output quality from machine tools relies on systematic calibration to imp...
Article
To meet the requirement of both high speed and high accuracy 3D measurements for dimensional metrology, multi-sensor measuring systems have been developed to measure, analyse and reverse engineer the geometry of objects. This paper presents a new development in coordinate unification called the “centroid of spherical centres” method, which can be u...
Article
Full-text available
When calibrating a machine tool, multiple measurement tasks will be performed, each of which has an associated uncertainty of measurement. International Standards and best-practice guides are available to aid with estimating uncertainty of measurement for individual tasks, but there is little consideration for the temporal influence on the uncertai...
Article
This paper proposes and discusses an active dual-sensor autofocusing method for measuring the positioning errors of arrays of small holes on complex curved surfaces. The dual-sensor unit combines an optical vision sensor and a tactile probe and is designed to achieve rapid automated measurements in a way that can be adapted to be suitable for deplo...
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This paper presents and evaluates an active dual-sensor autofocusing system that combines an optical vision sensor and a tactile probe for autofocusing on arrays of small holes on freeform surfaces. The system has been tested on a two-axis test rig and then integrated onto a three-axis computer numerical control (CNC) milling machine, where the aim...
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Manufacturing of high-quality components and assemblies is clearly recognised by industrialised nations as an important means of wealth generation. A “right first time” paradigm to producing finished components is the desirable goal to maximise economic benefits and reduce environmental impact. Such an ambition is only achievable through an accurat...
Conference Paper
Full-text available
Abstract The application of industrial robots for machining of complex parts is a very promising field that refers to the ability of the robot to produce parts with complex geometries that typically requires multi-axes machine tools. However, there are many restrictions that limit the use of robot in advanced manufacturing industry such as positio...
Conference Paper
Full-text available
Reducing downtime and assuring a high degree of accuracy of production machines, especially machine tools, have become increasingly important as the demand for higher production rates and closer tolerance continues to grow. The growing understanding of the importance of both calibration and maintenance in the evolving industrial scenario and the te...
Conference Paper
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This research work describes an intelligent and modular architecture for controlling the milling process. For this purpose, it is taking into account the admissible input cutting parameters given by the stability lobes and restrictions of the system, calculating the quasi-optimal cutting parameters. The quasi-optimal cutting parameters are obtained...
Conference Paper
Full-text available
Thermal errors are often quoted as being the largest contributor to inaccuracy of CNC machine tools, but they can be effectively reduced using error compensation. Success in obtaining a reliable and robust model depends heavily on the choice of system variables involved as well as the available input-output data pairs and the domain used for traini...
Conference Paper
Full-text available
Although designed to be structurally stiff, machine tool deformation takes place due to the various sources of errors such as shifting mass, component weight, temperature etc. In order to facilitate research activities and acquire further scientific insight on the deformation process, a computer-based on-line monitoring system has been developed. A...
Conference Paper
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This paper presents a novel control architecture system which is composed of a multi-objective cost function which Pareto optimizes the programming of cutting parameters while controlling the milling process to new cutting conditions if new constraints appear. The paper combines a self-optimized module which looks for and finds Pareto optimal cutti...
Conference Paper
Machine tool failures in industrial organisations disturb production operations and cause production loss. Predictive maintenance is one approach which has been successfully applied in some circumstances to allow scheduled production stoppages. It is an approach that reduces the need for reactive maintenance. Predictive maintenance is a tool that h...