Digital Twin of an Optical Measurement System.

Digital twins of measurement systems are used to estimate their measurement uncertainty. In the past, virtual coordinate measuring machines have been extensively researched. Research on digital twins of optical systems is still lacking due to the high number of error contributors. A method to describe a digital twin of an optical measurement system is presented in this article. The discussed optical system is a laser line scanner mounted on a coordinate measuring machine. Each component of the measurement system is mathematically described. The coordinate measuring machine focuses on the hardware errors and the laser line scanner determines the measurement error based on the scan depth, in-plane angle and out-of-plane angle. The digital twin assumes stable measurement conditions and uniform surface characteristics. Based on the Monte Carlo principle, virtual measurements can be used to determine the measurement uncertainty. This is demonstrated by validating the digital twin on a set of calibrated ring gauges. Two validation tests are performed: the first verifies the virtual uncertainty estimation by comparison with experimental data. The second validates the measured diameter of different ring gauges by comparing the estimated confidence interval with the calibrated diameter.

A Micro-Computed Tomography Comparison of the Porosity in Additively Fabricated CuCr1 Alloy Parts Using Virgin and Surface-Modified Powders.

Recently, the use of novel CuCr1 surface-modified powder for reliable laser powder-bed fusion (LPBF) manufacturing has been proposed, enabling a broader LPBF processing window and longer powder storage life. Nevertheless, virgin CuCr1 powder is also LPBF processable, on the condition that a high-energy density is employed. In this work, we compare two dense specimens produced from virgin and surface-modified CuCr1 powder. Furthermore, a third sample fabricated from surface-modified powder is characterized to understand an abnormal porosity content initially detected through Archimedes testing. Utilizing high-resolution micro-CT scans, the nature of the defects present in the different samples is revealed. Pores are analyzed in terms of size, morphology and spatial distribution. The micro-CT data reveal that the virgin CuCr1 dense specimen displays keyhole pores plus pit cavities spanning multiple layer thicknesses. On the other hand, the sample fabricated with the surface-modified CuCr1 powder mainly contains small and spherical equi-distributed metallurgical defects. Finally, the CT analysis of the third specimen reveals the presence of a W contamination, favoring lack-of-fusion pores between subsequent LPBF layers. The LPBF melting mode (keyhole or conductive), the properties of the material, and the potential presence of contaminants are connected to the different porosity types and discussed.

On the influence of second use, future battery technologies, and battery lifetime on the maximum recycled content of future electric vehicle batteries in Europe.

The European Union is promoting the uptake of low emission vehicles to reduce greenhouse gas emissions from transportation. However, this transition will increase the demand for five important battery raw materials; i.e. lithium, nickel, cobalt, copper, and graphite. Therefore, a substance flow analysis and forecasting model are proposed to investigate the flow of these materials through the different lifecycle stages of electric vehicle batteries. The model forecasts that by 2040, the vehicle stock will be from 72 to 78 million vehicles, while the second use stock will be from 3 to 11 million batteries. In addition, the annual recycling waste stream in 2040 will grow to roughly 3 million batteries with a capacity of 125 GWh. Results indicate that this waste stream could cover between 10% and 300% of future raw materials demand for electric vehicles. The width of this range is dominated by uncertainties on the rapidly evolving material composition of automotive batteries and the possible commercialization of cobalt-free battery technologies. The remaining uncertainty is attributed to the battery lifetime in vehicle use and potential second use of retired batteries.

Description and validation of a circular padding method for linear roughness measurements of short data lengths.

Surface topography measurements are vital in industrial quality control. Linear roughness measurements are among the most preferred methods, being quick to perform and easy to interpret. The ISO 16610 standard series prescribes filters that can be used for most cases, but has limitations for restricted measurement lengths. This is because the standard filter type is a Gaussian filter, which like most instances of kernel convolution filters has no output near the edges of the profile, effectively shortening the length of the filtered output profile as compared to the input. In some cases, this leads to a lack of representative data after filtration. Especially in fields such as Additive Manufacturing (AM) this becomes a problem, due to the high "roughness to measurable data length"-ratio that characterizes complex AM parts. This paper describes a method that allows to overcome this limitation:•A method for circular padding of short measured tracks is described and validated.•A flexible profile data post-processing tool was developed in MATLAB to grant users more control over the data analysis. Results obtained from roughness profiles long enough for normal ISO procedures are shown to not change significantly when circularly padded. When only a shorter section of the data is available, where the standard protocol would not be able to compute a filtered profile and related parameters anymore, the circular padding method is shown to lead to results that are in good agreement with the ISO standard procedures.

U-net-based blocked artifacts removal method for dynamic computed tomography.

Airplane engines are vital aircraft components, so regular inspections of the engines are required to ensure their stable operation. A dynamic computed tomography (CT) system has been proposed by our group for in situ nondestructive testing of airplane engines, which takes advantage of the rotor's self-rotation. However, static parts of the engines cause blocked artifacts in the reconstructed image, leading to misinterpretations of the condition of engines. In this paper, in order to remove the artifacts produced by the projection of the static parts in CT reconstruction, two deep-learning-based methods are proposed, which use U-Net to perform correction in the projection domain. The projection of static parts can be estimated by a well-trained U-Net and subsequently can be subtracted from the projections of the engine. Finally, the rotor can be reconstructed from the corrected projections. The results shown in this paper indicate that the proposed methods are practical and effective for removing those blocked artifacts and recovering the details of rotating parts, which will, in turn, maximize the utilization of the dynamic CT system for in situ engine tests.

Ease of disassembly of products to support circular economy strategies.

Circular economy strategies encourage, among others, concrete actions to extend the product lifetime. Product's repair and reuse, and component harvesting for reuse, all require the facilitated access to product components. Consequently, a reduction of the disassembly time and the related costs will increase the economic feasibility of product lifetime extension and therefore increase the viability of a circular economy in industrialised regions. Furthermore, disassembly has the potential to significantly increase the recycling yield and purity for precious metals, critical metals and plastics. For this reason, the European Commission and several ecolabels have considered to include design for disassembly requirements in legislation or voluntary environmental instruments. However, up to date, there is no standardised method to evaluate the ease of disassembly in an unambiguous manner with a good trade-off between the efforts required to apply the method and the accuracy of the determined disassembly time. The article proposes a robust method "eDiM" (ease of Disassembly Metric), to calculate the disassembly time based on the Maynard operation sequence technique (MOST). A straightforward calculation sheet is employed in eDiM to calculate the disassembly time given the sequence of actions and basic product information. This makes the results fully verifiable in an unambiguous manner, which makes eDiM suited to be used in policy measures in contrast to the results of prior developed methods One of the innovative aspects of eDiM is the categorization of disassembly tasks in six categories, which provides better insights on which disassembly tasks are the most time consuming and how the product design could be improved. The proposed method is illustrated by means of a case study of an LCD monitor. The presented case study demonstrates how the proposed method can be used in a policy context and how the calculated disassembly times per category can provide insights to manufacturers to improve the disassemblability of their products. The results also demonstrate how the proposed method can produce realistic results with only limited detail of input data.

Forecasting waste compositions: A case study on plastic waste of electronic display housings.

Because of the rapid succession of technological developments, the architecture and material composition of many products used in daily life have drastically changed over the last decades. As a result, well-adjusted recycling technologies need to be developed and installed to cope with these evolutions. This is essential to guarantee continued access to materials and to reduce the ecological impact of our material consumption. However, limited information is currently available on the material composition of arising waste streams and even less on how these waste streams will evolve. Therefore, this paper presents a methodology to forecast trends in the material composition of waste streams. To demonstrate the applicability and value of the proposed methodology, it is applied to forecast the evolution of plastic housing waste from flat panel display (FPD) TVs, FPD monitors, cathode ray tube (CRT) TVs and CRT monitors. The results of the presented forecasts indicate that a wide variety of plastic types and additives, such as flame retardants, are found in housings of similar products. The presented case study demonstrates that the proposed methodology allows the identification of trends in the evolution of the material composition of waste streams. In addition, it is demonstrated that the recycling sector will need to adapt its processes to deal with the increasing complexity of plastics of end-of-life electronic displays while respecting relevant directives.

Spark Plasma Sintering As a Solid-State Recycling Technique: The Case of Aluminum Alloy Scrap Consolidation.

Recently, "meltless" recycling techniques have been presented for the light metals category, targeting both energy and material savings by bypassing the final recycling step of remelting. In this context, the use of spark plasma sintering (SPS) is proposed in this paper as a novel solid-state recycling technique. The objective is two-fold: (I) to prove the technical feasibility of this approach; and (II) to characterize the recycled samples. Aluminum (Al) alloy scrap was selected to demonstrate the SPS effectiveness in producing fully-dense samples. For this purpose, Al alloy scrap in the form of machining chips was cold pre-compacted and sintered bellow the solidus temperature at 490 °C, under elevated pressure of 200 MPa. The dynamic scrap compaction, combined with electric current-based joule heating, achieved partial fracture of the stable surface oxides, desorption of the entrapped gases and activated the metallic surfaces, resulting in efficient solid-state chip welding eliminating residual porosity. The microhardness, the texture, the mechanical properties, the microstructure and the density of the recycled specimens have been investigated. An X-ray computed tomography (CT) analysis confirmed the density measurements, revealing a void-less bulk material with homogeneously distributed intermetallic compounds and oxides. The oxide content of the chips incorporated within the recycled material slightly increases its elastic properties. Finally, a thermal distribution simulation of the process in different segments illustrates the improved energy efficiency of this approach.

Environmental impact of incineration of calorific industrial waste: rotary kiln vs. cement kiln.

Rotary kiln incinerators and cement kilns are two energy intensive processes, requiring high temperatures that can be obtained by the combustion of fossil fuel. In both processes, fossil fuel is often substituted by high or medium calorific waste to avoid resource depletion and to save costs. Two types of industrial calorific waste streams are considered: automotive shredder residue (ASR) and meat and bone meal (MBM). These waste streams are of current high interest: ASR must be diverted from landfill, while MBM can no longer be used for cattle feeding. The environmental impact of the incineration of these waste streams is assessed and compared for both a rotary kiln and a cement kiln. For this purpose, data from an extensive emission inventory is applied for assessing the environmental impact using two different modeling approaches: one focusing on the impact of the relevant flows to and from the process and its subsystems, the other describing the change of environmental impact in response to these physical flows. Both ways of assessing emphasize different aspects of the considered processes. Attention is paid to assumptions in the methodology that can influence the outcome and conclusions of the assessment. It is concluded that for the incineration of calorific wastes, rotary kilns are generally preferred. Nevertheless, cement kilns show opportunities in improving their environmental impact when substituting their currently used fuels by more clean calorific waste streams, if this improvement is not at the expense of the actual environmental impact.