Browsing by Author "Giusca, Claudiu"
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Item Open Access Areal artefact manufacturing using SPDT(2018-08) Zhao, Junguo; Giusca, Claudiu; Goel, SauravWith the increasing importance of the surface engineering, surface topography measuring instrument has been used in wider range of applications, which requires trustworthy calibration process to deliver traceability so that the instrument is able to give comparable and reliable measurement. The calibration standard / artefact is designed to transfer traceability easily and reliably. In current market, the feature of the artefact used for evaluation the surface topography measuring process are not sufficiently accurate. This insufficiency may be solved by using certain types of calibration standard specified in ISO standard however they are not commercially produced. In this project, one of the desired types called ‘radial sinusoidal shape’ was produce by SPDT (single point diamond turning) manufacturing method. The feature parameters of the artefact are designed to meet the instrument measurement requirement and the machining path is generated with consideration of the tooling geometry. To assess the repeatability in z direction of the turning machine, a step height experiment was designed and conducted. The measurement result indicates that the repeatability of the machine is unsatisfactory when the feed distance smaller than 100 nm. The wavelength and the amplitude of machined radial sinusoidal shape was measured by stylus profiler, followed by the measurement uncertainty analysis. The measurement result was compared with the design to evaluate quality of the manufacturing process. To estimate the systematic error of the profiler, CCI was used to measure the machined radial sinusoidal shape. The measurement result was also compared with the design.Item Open Access An automated surface determination approach for computed tomography(Elsevier, 2022-06-23) Yang, Xiuyuan; Sun, Wenjuan; Giusca, ClaudiuSurface determination is a critical image processing step in X-ray Computed Tomography that uses algorithms based on local thresholding methods, such as Canny and Steinbess, to detect the surface of metallic components with intricate designs and complex topographies. In most of the cases, these algorithms require trial-and-error tests to optimise the threshold operation, leading to unreliable and, at times, erroneous inspection results. This paper demonstrates the ability of marker-controlled watershed algorithm to automate the surface determination process and to maintain its robustness in the presence of beam hardening and complex topographies, outperforming the current commercial and non-commercial software implementations.Item Open Access Data for the paper "Molecular dynamics simulation of the elliptical vibration assisted machining (EVAM) of pure iron"(Cranfield University, 2018-07-31 16:20) Goel, Saurav; Duarte martinez, Fabian; Giusca, ClaudiuData files used for figures 3 and 5 in the associated article from the Journal of Micromanufacturing. These need to be opened in the Origin software (https://www.originlab.com/).Item Open Access Data supporting: 'An automated surface determination approach for computed tomography'(Cranfield University, 2022-08-31 17:00) Yang, Xiuyuan; Giusca, Claudiu; Sun, WenjuanThis dataset contains the reconstructed simulation data, MCW surface point clouds, measurement results used for Fig 14 and Fig 16.Item Open Access Digital twin concept of a force measuring device based on the finite element method(International Measurement Confederation (IMEKO), 2023-03-28) Baer, Oksana; Giusca, Claudiu; Kumme, Rolf; Prato, Andrea; Sander, Jonas; Mirian, Davood; Hauschild, FrankIn the framework of EMPIR project ComTraForce, the Digital Twin (DT) concept of force measurement device is developed. DT aims to shade static, continuous as well as dynamic calibration processes, preserving data quality and collecting calibration data for improved Decision-making. To illustrate the developed DT concept, a prototype realisation for static and continuous force calibration processes is developed, involving simulation with ANSYS engineering software. The focus of the current work is placed on the data connection between the physical device and the DT. The DT model is validated using traceable measurements.Item Open Access Establishment of X-ray computed tomography traceability for additively manufactured surface texture evaluation(Elsevier, 2021-12-14) Sun, Wenjuan; Giusca, Claudiu; Lou, Shan; Yang, Xiuyuan; Chen, Xiao; Fry, Tony; Jiang, Xiangqian; Wilson, Alan; Brown, Stephen; Boulter, HalMetal additively-manufactured (AM) parts are increasingly used as safety-critical components in industry. Surface textures of metal AM parts are different to conventionally machined surfaces and can directly influence the functional performance of the parts. However, it is difficult or impossible to access and measure non-line-of-sight AM surfaces by conventional measurement techniques. X-ray computed tomography (XCT) is a promising technique that can measure non-line-of-sight surfaces non-destructively. However, the metrology framework for XCT to evaluate surface texture of AM parts is yet to be fully established, and there is a lack of development in surface texture reference standards that fit the purpose. In this paper, we have established a route to calibrate XCT for AM surface texture evaluation using a prototype three-dimensional roughness standard (3DRS) developed by the National Physical Laboratory that has a range of AM surface texture features and was designed for compatibility between 2D (profile), 2½D (areal), and tomography measuring instruments. A measurement protocol has been established between XCT and the contact stylus system, and uncertainty evaluation of 3DRS surface texture was established.Item Open Access Fabrication of functionalised surfaces on gum metal (Ti-30Nb) using micromachining(euspen, 2019-06-30) Hawi, Sara; Dickins, Andrew; Pardal, Goncalo; Giusca, Claudiu; Pearce, Oliver; Goel, SauravStructured surfaces are attracting deep interest, as they allow tailoring the functionality via changes in the surface topography. Applications for these surfaces range greatly, including, optical surfaces for antireflective surfaces, thermal structures to assist in heat dispersion and anti-fouling surfaces to reduce micro-organisms from adhering to components. Gum metal is a relatively newer kind of beta titanium alloy that has earmarked its place as the next generation Ortheopedic implant material. In a timely effort, this work investigated the generation of micron level structured surfaces on Gum metal (Ti-30Nb – a beta titanium alloy) to explore micromilling as the robust scalable process to achieve low dimensional surfaces in titanium alloy. During micromilling, the feedrate, spindle speed, axial depth of cut and tool step over were varied to optimise these parameters for achieving superior quality of machining.Item Open Access Fabrication of micro-scale features on titanium alloys through micromilling.(2018-04) Dickins, Andrew; Goel, Saurav; Giusca, ClaudiuStructured surfaces are of high interest in the manufacturing world, allowing for functionality to be applied to materials through nothing more than a change in the surface topography or an application of a surface coating. Applications for these surfaces range greatly, including, optical surfaces for antireflective surfaces, thermal structures to assist in heat dispersion and anti-fouling surfaces to reduce organisms from adhering to components. Hydrophobic structures, such as the one that have been examined on the lotus leaf under SEM, generate high droplet contact angles and roll off. The manipulation of surface wettability is of particular interest in areas such as the medical sector for self-cleaning applications or controlling cell adhesion on the surface of an implant. This work investigates the generation of micron level hydrophobic features on two Titanium alloys, Ti-6Al-4V alpha-beta alloy and Ti-30Nb beta alloy, with the aim of identifying how accurately surface structures can be produced through micromilling as well as experimentally testing how successfully these surfaces function after being fabricated. On each alloy, nine different 5mm x 5mm test pillars are machined using micromilling, half of each pillar is machined with 200μm wide and 30μm deep channels, generating a hydrophobic groove structure, and the other half being flat machined. Across these nine pillars the feedrate, spindle speed, axial depth of cut and tool step over were varied to optimise these parameters in terms of structure generation, channel bottom surface roughness and tool to workpiece interaction in an attempt to determine how effective micromilling is as at structuring the surface of beta Titanium alloys. Tool condition was assessed qualitatively using SEM imaging and an independent assessment was carried out to determine the mechanical properties of the beta Titanium alloy being machined.Item Open Access In process temperature monitoring of energy beam processing.(Cranfield University, 2019-07) Frumosu, Lydia; Huang, Zhaorong; Giusca, ClaudiuThe use of non-thermal and atmospheric plasma has been growing in recent years. Applications in wound sterilisation, food decontamination, cleaning and the more traditional machining and deposition are just some of the areas in which new technology is being developed. With the growing use of cool plasma comes the requirement to test and understand the temperature distribution of the jets. Current methods into temperature measurement revolve around spectroscopy and other non-contact methods. Spectroscopy can pose a challenge as a measurement device as it lacks the ability to measure overall gas temperatures in non-thermal plasmas. Contact measurement thermometers, such as thermocouples and resistance temperature detectors are an alternative which can provide an insight into the temperature of the ions and neutral species. However these sensors pose a challenge in gaining accurate or precise temperature measurements due to their susceptibility of electromagnetic interference. Fibre Bragg grating sensors have the ability of measuring both temperature and strain without electromagnetic interference. They possess the ability of multiplexing, being able to measure multiple temperatures across a single fibre, which can aid in measuring over a long distance. They also have the added benefit of being small, lightweight and have quick thermal response times. Additionally their small heat capacity reduces the effect on the temperature of the measurand, improving their accuracy over other physical probes. In this experiment fibre Bragg grating sensors 600 μm and 1000 μm in length and 10μm in diameter have been used to characterise the temperature distribution of non- thermal microwave plasma and thermal radio frequency plasma jets. Thermocouples have been used to compare results against current technologies. Results show the fibre Bragg grating sensors have been successful in determining plasma temperature changes over time, distance and across a variety of different parameters.Item Open Access A laser-based multilateration system for measurement of metre-scale low-slope freeform non-specular surfaces.(Cranfield University, 2019-02) Norman, James P.; Tonnellier, Xavier P.; Giusca, ClaudiuThe manufacture of metre–scale mirror segments for telescopes requires measurement with low uncertainty to enable accurate form correction. The uncertainty of this measurement has a direct effect upon the time to manufacture these segments; it is therefore critical, to the viability of large optic manufacture, that a method for low uncertainty measurement of these surfaces is developed and evaluated. The state-of-the-art system for measurement of metre–scale surfaces has a length measurement uncertainty of 1.2 µm over 1 m. Multilateration is a method for determining Cartesian coordinates of measured positions utilising range displacement measuring stations. A four laser tracker multilateration system has been proposed and tested with the aim to determine whether a system can measure the specified surfaces with measurement uncertainties below 1 µm. Influence factors that affect the multilateration input parameters have been identified and utilised in Monte Carlo simulation of the multilateration system to estimate the uncertainty associated with the coordinate measurement. A small flat optic (0.2 m 0.2 m) was measured with the multilateration measurement setup to have z-coordinates with a standard deviation, σz = 0.25 µm, and a large flat optic (0.4 m 0.4 m) was measured with the multilateration measurement setup to have z-coordinates with a standard deviation, σ∆ z = 0.73 µm. The 10 x 10 point multilateration measurement of the large optic was repeated 10 times; the 100 points on the surface have a square root mean variance, σz = 0.46 µm. Monte Carlo simulations indicate the independence of measurement area and measurement noise for the experimental setup tested. It is concluded that a laser–based multilateration system can measure a metre–scale optic with z-coordinate measurement uncertainty below 1 µm. A 15.5 h measurement of the larger flat was carried out to determine the effect of time dependent parameters on measurement uncertainty. The measurement solution had a standard deviation of 1.88 µm: a factor of approximately 2.4 times the equivalent short–term multilateration measurement solution. Simulations have shown how this measurement drift is strongly related to temperature change in the local environment of the measurement setup. This has been confirmed by long–term measurements of laser tracker stationary SMR.Item Open Access Manufacturing uncertainty: How reproducible is the depth of cut during turning of OFHC copper?(EUSPEN, 2018-06) Zhao, Junguo; Giusca, Claudiu; Goel, SauravSingle point diamond turning (SPDT) used for micromachining has emerged as an indispensable and high-volume production manufacturing process for shaping and finishing various materials. As a preliminary testbed study, this paper investigates manufacturing uncertainty in SPDT originating from controllable and uncontrollable sources of errors. A Moore Nanotech 350 UPL SPDT machine was employed to perform repeat cutting of step heights on OFHC copper substrate at fine cutting depths in the range of 50 nm to 500 nm. The metrology was performed by a contact stylus profilometer from Taylor Hobson. While a great deal of uncertainty was observed in the results, a stark observation was that the programmed and actual depth of cuts differed less nearer at the centre of rotation of the substrate as opposed to periphery of the substrate demonstrating that the machining achieved least uncertainty nearer to the centre of rotation. A hypothesis is accordingly proposed for achieving more deterministic certainties from SPDT.Item Open Access Parasitic load components for torque and force calibration: a digital twin concept(Oldenbourg Verlag, 2023-07-05) Mienert, Kai; Baer, Oksana; Giusca, Claudiu; Prato, AndreaThe 5 MN m standard torque machine within the Competence Centre for Wind Energy (CCW) was developed at PTB. The Digital Twin (DT) of the torque transducer mounted inside the machine was developed to enable errors eliminations and resources optimization during operation. The machine can apply not only torque, but also bending moments and shear forces. At the same time, the DT concepts of force measurement devices and their application for static, continuous and dynamic calibrations was developed to improve calibration processes, preserve data quality and collect calibration data for improved decision making. In order to illustrate the functionality of both developed DT concepts, a study of parasitic load components in both devices is carried out using simulation with ANSYS and ABAQUS engineering software. The validation of the DT models was carried out using traceable measurements. The way to combine both concepts for comprehensive shading of the standard torque machine is discussed.Item Open Access The possibility of performing FEA analysis of a contact loading process fed by the MD simulation data(Elsevier, 2018-07-17) Goel, Saurav; Llavori, Iñigo; Zabala, Alaitz; Giusca, Claudiu; Veldhuis, Stephen C.; Endrino, José L.Item Open Access The study of influence factors in x-ray computed tomography using simulation approach.(2018-08) Yang, Xiuyuan; Giusca, Claudiu; Sun, WenjuanXCT simulation scanning was used throughout the study because simulation scanning has the flexibility in changing scanning parameters as well as improving the efficiency. The research investigated the effect of voltage, scattering-contamination and multi-sampling on the quality of 2D image projection. For The study tested factors of scattering-contamination, multi-sampling and cone-beam angle on dimensional measurement error with the numerical geometry samples including spheres, cubes, cylinders and tubes. For cylinders and tubes, the measurement of outer diameter leaded more deviation than inner diameter. Scattering contamination had limited influencing (up to 1/35 of the voxel size) to the measurement result but scattering contamination can amplify the operator factor in the geometry determination step. 3X3 multi-sampling detector could optimise the measurement result when measuring the diameter of the cylinder. On the other hand, the effectiveness of the application of multi-sampling is related to the geometry features for measure, and the effect is independent to the scattering-contamination. When measuring circles on the tube, the cone-beam angle had only slight influence (up to 1/131 of voxel size) on the measurement error.Item Open Access Surface determination algorithm for accurate XCT bidirectional length measurements(Elsevier, 2023-09-23) Yang, Xiuyuan; Sun, Wenjuan; Giusca, ClaudiuSurface determination plays an important role in XCT bi-directional length measurement, however, its effect on the measurement results is often overlooked or hidden by other error sources. Most of the published research in dimensional field used the Canny algorithm or the surface determination module in VGStudio. Both of them require input from the operator that can also affect the accuracy of the measurements. Alternatively, the marker-controlled watershed (MCW) algorithm has been proven to avoid the latter issue, however, there is no systematic study that evaluated the surface determination algorithm's effect on the accuracy of bi-directional length measurements. In this study a two-sphere reference sample was measured using an XCT scanner and, with the aid of simulations, the effect of the three surface determination methods on bi-directional length measurements was comprehensively studied. The results show that in the presence of ‘streak’ artefacts, a beam hardening error, if the operator does not set parameters appropriately, Canny and VGStudio implementations lead to either loss of surface or large errors, whereas MCW avoids this issue demonstrating its process automation ability. Nevertheless, with voxel calibration, beam hardening correction and data manipulation, MCW and Canny algorithms enable accurate sphere radius measurements (bi-directional measurements), comparable to the accuracy of an industrial tactile coordinate measuring machine.Item Open Access Topography of selectively laser melted surfaces: A comparison of different measurement methods(Elsevier, 2017-04-29) Thompson, Adam; Senin, Nicola; Giusca, Claudiu; Leach, RichardSelective laser melting (SLM) of metals produces surface topographies that are challenging to measure. Multiple areal surface topography measurement technologies are available, which allow reconstruction of information rich, three-dimensional digital surface models. However, the capability of such technologies to capture intricate topographic details of SLM parts has not yet been investigated. This work explores the topography of a SLM Ti6Al4V part, as reconstructed from measurements by various optical and non-optical technologies. Discrepancies in the reconstruction of local topographic features are investigated through alignment and quantitative assessment of local differences. ISO 25178-2 areal texture parameters are computed as further comparison indicators.Item Open Access Ultra precision air bearing development for low cost manufacturing.(2018-04) Sen, Aroop Kumar; Goel, Saurav; Giusca, ClaudiuAir bearings today are extensively used in the industry, the manufacturing processes involved in fabricating these bearings are complicated and have major drawbacks. The current research investigates the failure of aerostatic bearings based upon which a manufacturing process is developed which removes the correlation between the bearing surface and the effective gap between these surfaces. This results in low manufacturing errors due to the omission of repeated machining of the bearing surface. The second factor that is novelty towards this research is the application of aluminium coated with hard nickel as suitable alternative to bearing base material instead to the current material for aerostatic bearings. This proposed material solution has low density, good wear resistance and good corrosion resistance. This allows the application of diamond turning instead of precision grinding as the bearing machining process. Reducing on majority of the manufacturing while achieving the form accuracy of the bearing surface. The third novelty factor is the application of bi-conic configuration which would allow self-aligning capability and has a smaller packaging size as compared to any other fluid film mechanical configuration.