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ispartof: Proceedings of iCT2017 - 7th Conference on Industrial Computed Tomography ispartof: Conference on Industrial Computed Tomography location:Leuven date:7 Feb - 9 Feb 2017 status: published

ispartof: Proceedings of iCT2017 - 7th Conference on Industrial Computed Tomography ispartof: Conference on Industrial Computed Tomography location:Leuven date:7 Feb - 9 Feb 2017 status: published

ispartof: Proceedings of iCT2017 - 7th Conference on Industrial Computed Tomography ispartof: Conference on Industrial Computed Tomography location:Leuven date:7 Feb - 9 Feb 2017 status: submitted

ispartof: pages:1-7 ispartof: Going Green Care Innovation 2018 pages:1-7 ispartof: Going Green Care Innovation 2018 location:Vienna, Austria date:27 Nov - 29 Nov 2018 status: Published online

ispartof: pages:1-10 ispartof: Going Green – CARE INNOVATION 2018 Proceedings. Towards a Resource Efficient Economy. pages:1-10 ispartof: Going Green - Care Innovation - 7th International Symposium and Environmental Exhibition location:Vienna, Austria date:26 Nov - 29 Nov 2018 status: Published online

Error motions of the rotation stage in X-ray computed tomography instruments can affect the quality of measurements performed on the acquired data. The effects of rotation stage errors are evaluated for simulated CT measurements of a simple test object at various magnification positions. The magnitude and functional behavior of simulated stage errors correspond to the acceptance limits in the specifications of the Newport RVS80CC rotation stage employed by a Nikon 225kV CT system. Dimensional errors in the simulated CT measurements in the presence of rotation stage errors are compared to the same measurements simulated in the absence thereof. A discussion on the sensitivity of CT measurements to rotation stage errors is given.

ispartof: Proceedings 12th International Conference on CFD in Oil & Gas, Metallurgical and Process Industries ispartof: 12th International Conference on CFD in Oil & Gas, Metallurgical and Process Industries location:Trondheim, NORWAY date:30 May - 1 Jun 2017 status: published

For high measurement accuracy with X-ray computed tomography (CT), that requires no scale calibration afterwards, due to incorrect assessment of voxel size during a CT scan, object magnification needs to be precisely calculated in order to minimize scale error of the reconstructed volume. Magnification, which is given by the z-axis of the machine’s coordinate system, is defined by the ratio between the source-detector (SDD) and source-rotation axis distances (SRD). An inaccurate definition of either thereof distances leads to error in voxel size which by itself results in scale error of the reconstructed volume. A correct assessment of these distances is therefore of paramount importance. In this work, a new methodology to correctly assess SDD and SRD is presented. The procedure bases itself in the use of radiographs acquired along the magnification axis rather than whole 3D scans. The newly developed method provides an accurate and fast way of calibrating both distances, improving dimensional metrology and quality control by X-ray CT. Boundary conditions, that enable the new methodology to work, were studied, tested and validated with both simulation and real data sets. Preliminary results indicate that the proposed calibration methodology reduces length error deviations in the measurements of a calibrated test object ispartof: pages:1-2 ispartof: 7th Conference on Industrial Computed Tomography, Leuven, Belgium (iCT 2017) pages:1-2 ispartof: 7th Conference on Industrial Computed Tomography, Leuven, Belgium (iCT 2017) location:Leuven - Belgium date:1 Jan - 2 Jan 2017 status: published

Cone-beam computed tomography (CT) with circular scanning trajectory is known to suffer from so called cone-beam artifacts. Cone-beam artifacts are errors in the reconstructed volume due to incomplete radon data. These artifacts increase with increasing distance of the reconstructed plane from the midplane, i.e. the plane containing the X-ray source. Theoretically, the midplane represents the ideal data set for tomographic reconstruction as the entire set of line integrals, i.e. the X-ray attenuation trajectories, are parallel to the plane they are used to reconstruct. The angle between the reconstructed plane and the line integrals used to reconstruct it increases with increasing distance from the midplane. Cone-beam artifacts generally result in a degradation of tomographically reconstructed edges, subsequently affecting dimensional measurements. Appearance of cone-beam artifacts depends on the position and orientation of the object under investigation in the measurement volume. In this paper we propose an algorithm that takes as an input the triangulated surface, e.g. a CAD model, of a scanned object and predicts where the object's surface cannot be reconstructed properly due to cone-beam artifacts. We apply Tuy's data sufficiency condition to define the analytical relationship between each surface triangle in the object model and the ability to reconstruct it using circular scan CT. The output of the proposed algorithm is the object position and orientation that reduces the effects of cone beam artifacts. The proposed algorithm is highly parallelizable and provides computational benefits when compared to conventional CT simulation methods. Operators of CT can use the proposed algorithm to reduce the influence of the cone-beam artifact on the measurements results. ispartof: The e-Journal of Nondestructive Testing issue:2017 ispartof: 7th Conference on Industrial Computed Tomography (iCT) location:KU Leuven, Leuven, Belgium date:7 Feb - 9 Feb 2017 status: published

ispartof: Metaforum position paper 15 pages:1-34 status: published

The focus of the presented research is on the mechanical recycling of post-consumer plastics from Waste Elec-trical and Electronic Equipment (WEEE) and End-of-Life Vehicles (ELVs). Currently only a limited number of these plastics are mechanically recycled on an industrial scale while the majority is thermally treated for en-ergy recovery. Since there is a significant potential for value recovery and to lower the environmental impact of plastics, the aim of the present research is to develop new mechanical recycling processes based on the dis-assembly of plastic components and the identification of the plastic by spectroscopic methods. This paper will present this distinct recycling process based on a case study of the recycling of Acrylonitrile Butadiene Sty-rene copolymer (ABS) from Liquid Crystal Display (LCD) TVs. The quality of the achieved recyclates is evaluated by mechanical testing and results showed high mechanical properties when compared to commer-cially recycled ABS. no ISSN ispartof: pages:307-312 ispartof: Proceedings of the 7th Bi-Annual International Polymers & Moulds Innovations Conference pages:307-312 ispartof: Polymers & Moulds Innovations location:Ghent status: published

The quality of dimensional measurements made by industrial X-ray computed tomography (CT) dependson a variety of influence factors in the measurement process. In this paper, the effects of angular misalignments of a flat-panel detector are investigated. First, a forward projection model is applied to evaluate distortions of the radiographic pixel coordinates assigned to X-ray intensities due to various detector rotation angles. Distortion maps are presented for a set of representative detector rotations and the sensitivity of image distortions to each rotation is discussed. It is shown from a simulation study that detector angular misalignments result in systematic errors of the reconstructed volume. The distortion model is inversely applied to generate correction maps that are used to correct the simulated radio-graphs from a misaligned detector. A new volume is reconstructed from the corrected radiographs and the new deviations are compared to the uncorrected results. The reduction of observed volumetric errors after radiographic correction validates the efficacy of the radiographic distortion model. Additionally,the output of this study can contribute to the development of a geometrical error model for volumetric measurements made by CT.

Laser Sintering is an Additive Manufacturing technique increasingly used to produce functional parts, with polyamide-12 (PA12) being by far the most processed material. It is common practice in industry to process a mix of recycled and virgin PA12 powder; however it is not yet fully understood how the Laser Sintering process parameters influence the microstructural composition for this mixture, namely the degree of crystallinity, the porosity characteristics and the distribution of the pores within the sintered parts. In this work X-ray Computed Tomography (CT) is used to investigate the porosity of tensile bars printed flatwise using a 50/50 mix of used and virgin PA12 processed with different Laser Sintering energy densities (EDs). Analysis of the pores characteristics and image processing of the CT-slices parallel to the building platform provide insights into the link between Laser Sintering process parameters, pores formation and their arrangement into the sintered polymer for different energy density levels. This information combined with the crystallinity values measured by Differential Scanning Calorimetry, gives a complete picture of the microstructure of the sintered material and its link with the resulting tensile properties. Published version

ispartof: pages:1112-1125 ispartof: Proceedings of 26th International Solid Freeform Fabrication Symposium pages:1112-1125 ispartof: International Solid Freeform Fabrication Symposium location:Austin date:8 Aug - 10 Aug 2016 status: published

Industrial x-ray computed tomography (XCT) is seen as a potentially effective tool for the industrial inspection of complex parts. In particular, XCT is an attractive solution for the measurement of internal geometries, which are inaccessible by conventional coordinate measuring systems. While the technology is available and the benefits are recognized, methods to establish the measurement assurance of XCT systems are lacking. More specifically, the assessment of measurement uncertainty and the subsequent establishment of measurement traceability is a largely unknown process. This paper is a review of research that contributes to the development of a geometrical calibration procedure for XCT systems. A brief introduction to the geometry of cone-beam tomography systems is given, after which the geometrical influence factors are outlined. Mathematical measurement models play a significant role in understanding how geometrical offsets and misalignments contribute to error in measurements; therefore, the application of mathematical models in simulating geometrical errors is discussed and the corresponding literature is presented. Then, the various methods that have been developed to measure certain geometrical errors are reviewed. The findings from this review are discussed and suggestions are provided for future work towards the development of a comprehensive and practical geometrical calibration procedure.

An extensive amount of today’s research within the field of dimensional metrology is dedicated to multi-sensor and non-contact measurements. Tactile probing on a coordinate measuring machine (CMM) however is inherently different. Although tactile probing is considered more accurate, it often ignores smaller surface details. In essence it means that tactile approaches measure a mechanically filtered surface while the non-contact measurement principles take into account most surface details. The research presented focuses on the offsets due to surface roughness between touch-trigger probing on a CMM and three non-contact measurement principles (X-ray computed tomography (CT), CMM camera vision and CMM laser line scanning). Results show significantly correlating trends between the offset and the surface roughness. ispartof: pages:189-190 ispartof: Proceedings of the 15th international conference of the european society for precision engineering and nanotechnology pages:189-190 ispartof: International conference of the european society for precision engineering and nanotechnology location:Leuven date:1 Jun - 5 Jun 2015 status: published

Polymeric parts produced by Laser Sintering (LS) present a consistent amount of pores with a wide pore size distribution. The knowledge about the porosity value and its distribution within the part allows to perform a quality control of the LS process, and gives insights on how to improve it. In this work the influence of the sample size on the porosity measurement is discussed, as well as its representativeness of the LS process itself. The reliability of the porosity measurement of those parts is assessed taking into account the influence of the Computed Tomography (CT) scanning parameters, the reconstruction and noise reduction algorithms. The quality of the CT datasets produced is assessed by calculating contrast-to-noise-ratio and signal-to-noise-ratio on representative reconstructed images. Repeatability of the measurements is also assessed along the entire workflow: CT acquisition, reconstruction and porosity measurement using commercial software packages. ispartof: International Symposium on Digital Industrial Radiology and Computed Tomography location:Ghent, Belgium date:22 Jun - 25 Jun 2015 status: published

Sensors for coordinate measuring machines (CMM) are nowadays assessed within a measurement system, i.e. while mounted onto a CMM. This means that the accuracy or uncertainty of the sensor or probe is not really identified on its own, but may be influenced by the accuracy or uncertainty of the CMM on which the accuracy testing is done. Determining the accuracy and repeatability of a sensor, apart from the machines uncertainty, could yield useful information in several cases. For instance sensor damage can be ruled out after a machine crash if the sensor could be tested apart from the machines uncertainty. Also testing a new sensor on an older machine sometimes poses a problem, as the sensors inaccuracy can vanish in the total uncertainty of the measuring system due to a high CMM uncertainty. This paper describes the current standardised and accepted methods for evaluating the integration of a CMM sensor in the environment of the machine. Furthermore tests are described to exclude the CMM uncertainty as best as possible to come to an assessment that characterises the sole sensor uncertainty. This is done through smart positioning of the reference tool, using another reference tool in combination with another measurement strategy or using extra equipment to exclude CMM errors. Preliminary results are presented and discussed. ispartof: pages:244-253 ispartof: Laser Metrology and Machine Performance XI pages:244-253 ispartof: 11th International Conference and Exchibition on Laser Metrolgy, Machine Tool, CMM & Robotic Performance location:Queensgate, West Yorkshire, UK. date:17 Mar - 18 Mar 2015 status: published

In industrialized countries, recycling of complex products, such as electronics, is predominantly based on mechanical comminution and automated material sorting. This recycling scheme is characterized by high recovery rates for certain materials, such as steel and aluminium, but underperforms for other materials like precious metals, critical metals and plastics, which are of high importance from both an environmental and economic perspective. On the other hand, disassembly or selective destructive removal of certain components can significantly increase the recovery rate of these materials. Recent initiatives to revise the European eco-label for electronic products recognize this issue, and aim to influence the design of electronic products in a way that disassembly becomes economically preferable for key components at end-of-life. For example, in the draft version of the eco-label criteria for LCD televisions, maximum disassembly times are proposed for Printed Wiring Boards and specific plastic components. The aim of this article is to analyse the environmental relevance of such an approach, and to provide insights to manufacturers on the improvements required to decrease disassembly time. Therefore, an in-depth analysis of both material composition and disassembly times for LCD TVs and monitors is performed. Environmental assessment is carried out by means of Life Cycle Assessment techniques. no isbn ispartof: pages:1-8 ispartof: Going Green – CARE INNOVATION 2014. Towards a Resource Efficient Economy pages:1-8 ispartof: Going Green – CARE INNOVATION 2014 location:Vienna, Austria date:17 Nov - 20 Nov 2014 status: published

Laser line scanning is a laser based measurement method to acquire dimensional information of a workpiece. The most common applications are found in e.g. automotive and medical industry. The advantages of laser line CMM probing are a high data density and a high measurement speed. This makes the probe ideal to measure three dimensional free form surfaces. To align freeform parts in a precise manner however, features (e.g. cylinders, spheres) are used to allocate the position. The newest generation of laser line scanners can have an MPEP of below 10µm. The first part of the paper presents a reference object with drilled holes of different diameters. The influences of the diameter of the feature and the in-plane viewing angle on the measuring depth range are investigated on this reference object. The results can then be converted to an aspect ratio limitation that restricts the feature dimensions for full inspection. The second part compares the accuracy and the repeatability of a Nikon Metrology LC60Dx digital laser line scanner and a Renishaw TP200 touch-trigger probe, using two case study objects that incorporate cylindrical features. The experimental case takes into account different surface finishes and the previously acquired results on the aspect ratio of the measurement. Both investigated sensors are equipped on the same CMM and are operated with the same software. ispartof: 10th IMEKO Symposium : Laser Metrology for Precision Measurement and Inspection in Industry (LMPMI) 2014 ispartof: LMPMI location:Tsukuba, Japan date:2 Sep - 5 Sep 2014 status: published

Due to increasing energy and resource costs at the one hand and upcoming regulations on energy and resource efficiency at the other, a growing interest of machine tool builders to the environmental performance of their machine tools can be observed today. The last decade, academic as well as industrial research groups started to assess the energy demand of discrete part manufacturing processes and indicated a significant potential for improvement. In contrast to conventional machining processes (e.g. milling, turning…), (sheet) metal forming processes are still less well documented in terms of their energy demand. In consequence, potential energy efficiency improvement measures for these processes are often not yet recognized. This contribution provides a short discussion on energy assessment methods followed by a structured overview of available studies on the energy demand of (sheet) metal forming processes. A range of identified energy efficiency improvement measures, suitable for these processes, is presented and quantified. ispartof: pages:59-72 ispartof: New Developments in Sheet Metal Forming pages:59-72 ispartof: Int. Conference on New Developments in Sheet Metal Forming location:Stuttgart date:12 May - 14 May 2014 status: published

Compared to other base metals, the refining options for aluminium during the final metallurgical recycling stage are very limited. These limited melt purification options, along with the relatively large number of alloys and the accumulation of alloying and foreign elements during the different life cycle stages, force the aluminium industry to operate in a cascade recycling chain. A Life Cycle Assessment (LCA) based,resource oriented approach, is presented in order to: i) assess the environmental impact calculation during aluminium recycling, ii) examine the scrap recycling loops and iii) express and quantify dilution and quality losses during recycling. Finally, this paper discusses, from an environmental point of view, strategies and opportunities for improved recycling as well as opportunities for more sustainable scrap management.Case studies focusing on major post-consumer scrap streams are examined based on their environmental performance in two different recycling scenarios. ispartof: pages:305-310 ispartof: , Proceedings of the 11th Global Conference on Sustainable Manufacturing - Innovative Solutions pages:305-310 ispartof: Global Conference on Sustainable Manufacturing location:Berlin date:23 Sep - 25 Sep 2013 status: published

Computed tomography is already a well established technology in medical and material analysis. Also for dimensional metrology applications, CT is a promising technique for measuring internal and external geometries. Nowadays, most industrial CT scanners, use 120 to 225 kV sources. To scan thicker and more absorbing materials, more power is needed. The Nikon Metrology XT H450 has a range up to 450 kV. However the accuracy of these new, more powerful machines has to be investigated. This accuracy study uses a calibrated reference object and simulations, to get a better understanding of the existing errors. This reference object is developed and produced by fixing CMM probing styli on a socket. It has been produced in several materials and used together with simulations to analyze the accuracy of single and multi-material CT measurements. For single material, accuracies up to 10-15 μm are achieved. In the case of multi material this accuracy deteriorates to 70-80 μm. Besides some mechanical errors which cause these deviations, the main factor is the edge detection. ispartof: pages:297-300 ispartof: Proceedings of the 11th IMEKO TC14 International Symposium on Measurement and Quality Control (ISMQC 2013) pages:297-300 ispartof: IMEKO TC14 International Symposium on Measurement and Quality Control (ISMQC 2013) location:Cracow, Poland date:11 Sep - 13 Sep 2013 status: published

Recently, X-ray CT technology has entered the application field of dimensional metrology, as alternative to tactile and optical 3D coordinate measuring techniques. Nevertheless, the measurement quality of industrial CT machines is affected by many parameters and phenomenon, among which beam hardening plays a crucial role. It has been proven that the accuracy and uncertainty of CT dimensional measurements is largely influenced by the applied beam hardening correction method. As a routine procedure in industry, the beam hardening effect is corrected by applying hardware pre-filtration complemented with a software correction that implies linearization using predefined polynomial fitting curves. This correction method can largely eliminate beam hardening artifacts e.g. cupping effect and streaks. However, measurement results reveal that the effectiveness of such method is closely related to the selected X-ray power and hardware filter. Over-correction often occurs with inappropriate machine settings, which results in dimensional errors. This paper investigates the correlation between X-ray power, filter and beam hardening correction parameters, and aims at establishing a procedure for defining the optimal beam hardening correction parameters for CT dimensional metrology applications. ispartof: pages:137-143 ispartof: International Conference on Competitive Manufacturing pages:137-143 ispartof: International Conference on Competitive Manufacturing location:Stellenbosch, South Africa date:30 Jan - 1 Feb 2013 status: published