Investigation of the influence of CO2 cryogenic coolant application on tool wear

The use of cryogenic coolants has emerged as an environmentally conscious alternative to emulsion coolant options. Cryogenic media can be delivered with a variety of methods to the cutting edge and they can be used in combination with other traditional coolant options such as Minimum Quantity Lubrication (MQL) and compressed air cooling in order to aid dissipation of heat generated in the cutting zone and maximize the lubrication of the cutting edge and thus prolong tool life. This study focuses on the investigation of tool life when milling aerospace grade titanium (Ti-6Al-4 V) under different coolant delivery options. Tool wear progression was recorded for the following coolant options: cryogenic CO 2 , emulsion flood cooling, dry machining, cryogenic CO 2 combined with air or MQL as well as MQL alone

Investigation of hybrid manufacturing of stainless steel 316L components using direct energy deposition

Direct energy deposition (DED) has been established as one of the methods for additive manufacturing metallic parts. The combination of DED capabilities with traditional machining centre capabilities has enabled over the past few years the creation of Hybrid manufacturing cells that are able to additively manufacture and finish machine components under one platform. This paper investigates the production of geometries using a hybrid, additive and subtractive approach. The parameters for depositing stainless steel 316L are initially investigated followed by an assessment of machinability of the additively manufactured material. Finally the quality of the deposited and machined material was thoroughly examined with a series of destructive and nondestructive methods

Material requirements for wind turbines

In this note, we provide updated estimates of the material intensities of 17 materials, in kg per MW of wind energy installed, based on the existing types of wind turbines.JRC.C.7 - Energy Transition Insights for Polic

Calculation of non-deformed chip and gear geometry in power skiving using a CAD-based simulation

Power skiving is a new machining process that allows the manufacturing of external and internal gears while achieving high throughputs. Although the process was first described during the nineteenth century, it is not until lately that advances in machine tool technology allowed for the process to be implemented on an industrial scale. This paper presents a novel simulation model that enables the accurate prediction of the non-deformed chip geometry, the form and dimensions of the chips produced during the cutting process as well as the characteristics of the gear gap. The simulation model is embedded on a CAD environment in order to take advantage of their increased accuracy. Through the simulation code, the virtual simulation of the manufacturing process is realised. The simulation model was verified with the use of analytical equations regarding the form of the gear. Chip geometry and dimensions for internal and external gears machined with different conditions are also presented

Development of cutting force model and process maps for power skiving using CAD-based modelling

Power skiving is a new gear cutting process that has been recognized to provide a step change in the production rate achieved in the machining of high-precision internal and external involute gears. The process is based on a continuous generating meshing between the workgear and the cutting tool. Understanding of the loads applied in the cutting tool, and therefore some of the sources of tool wear, have not been thoroughly understood. This paper presents a novel model that is able to predict with high accuracy the cutting forces in the power skiving process. The model is based on a solid modelling simulation algorithm that produces high-fidelity solid bodies that are used for the calculations. The results of the model have been experimentally validated. A series of process maps are also produced to assist in the identification of the optimal machining parameters

Comparison of a black-box model to a traditional numerical model for hydraulic head prediction

Two different methodologies for hydraulic head simulation were compared in this study. The first methodology is a classic numerical groundwater flow simulation model, Princeton Transport Code (PTC), while the second one is a black-box approach that uses Artificial Neural Networks (ANNs). Both methodologies were implemented in the Bavaria region in Germany at thirty observation wells. When using PTC, meteorological and geological data are used in order to compute the simulated hydraulic head following the calibration of the appropriate model parameters. The ANNs use meteorological and hydrological data as input parameters. Different input parameters and ANN architectures were tested and the ANN with the best performance was compared with the PTC model simulation results. One ANN was trained for every observation well and the hydraulic head change was simulated on a daily time step. The performance of the two models was then compared based on the real field data from the study area. The cases in which one model outperforms the other were summarized, while the use of one instead of the other depends on the application and further use of the model

Surface and sub-surface integrity of Ti-6Al-4V components produced by selective electron beam melting with post-build finish machining

The emergence of metal additive manufacturing (AM) processes offer manufacturers a promising alternative to traditional forging and casting techniques for the production of near net shape titanium alloy components. However, limitations in both the surface finish quality and the geometric accuracy of parts produced by AM means that post-build finish machining of the part remains to be a requirement to produce high precision components. Furthermore, the fatigue performance of material produced directly by these processes is often limited by both the poor surface finish and porosity related defects which occur within the material. This study investigates the implications of machining stock allowance on the surface integrity of Ti-6Al-4V specimens produced by selective electron beam melting (SEBM) followed by post-build finish machining. The study revealed that the exposure of porosity related defects on the newly machined surface varied depending on the depth of material removed from the as-built specimen surface during machining. Four point bend fatigue testing of the specimens was carried out to determine the effect of the exposed surface defects on the fatigue performance of the material. This study highlights that the non-uniform distribution of pores within SEBM Ti-6Al-4V means that careful considerations must be given regarding machining stock allowance in the design of these components due to the implications of material removal depth on surface integrity

European Climate Neutral Industry Competitiveness Scoreboard 2022

This policy brief is a self-standing summary based on the second annual report of European Climate Neutral Industry Scoreboard, which builds on the findings and framework developed in the study, ‘Climate neutral market opportunities and EU competitiveness’, conducted by the ICF and Cleantech Group for DG GROW in 2019-2020. The policy brief includes a short description of the scope of the study, a synthesis of the findings, summary scoreboards for the climate neutral solutions assessed and a summary of messages relevant for policy making The objective of the scoreboard is to assess the EU’s competitive position in climate-neutral solutions across important industrial ecosystems related to the energy transition. The previous assessment, the 2021 annual report, analysed 20 climate-neutral solutions, in the ecosystems of renewable energy, energy-intensive industry, mobility-transport-automotive, construction and electronics. This report provides an update of these 20 solutions and adds eight new climate-neutral solutions. The scoreboard is based on ten key indicators: public R&D investment, early and later stage private investment, patenting activity, number of innovating companies, employment, production, turnover, imports & exports and trade balance. For more details on the methodology, readers should consult the respective CIndECS technical document, on the protocol of the assessment methodology.JRC.C.7 - Energy Transition Insights for Polic

Climate change impact on the frequency of hydrometeorological extremes in the island of Crete

© 2019 by the authors. Frequency analysis on extreme hydrological and meteorological events under the effect of climate change is performed in the island of Crete. Data from Regional Climate Model simulations (RCMs) that follow three Representative Concentration Pathways (RCP2.6, RCP4.5, RCP8.5) are used in the analysis. The analysis was performed for the 1985-2100 time period, divided into three equal-duration time slices (1985-2010, 2025-2050, and 2075-2100). Comparison between the results from the three time slices for the different RCMs under different RCP scenarios indicate that drought events are expected to increase in the future. The meteorological and hydrological drought indices, relative Standardized Precipitation Index (SPI) and Standardized Runoff index (SRI), are used to identify the number of drought events for each RCM. Results from extreme precipitation, extreme flow, meteorological and hydrological drought frequency analysis over Crete show that the impact of climate change on the magnitude of 100 years return period extreme events will also increase, along with the magnitude of extreme precipitation and flow events

Milling of aerospace alloys using supercritical CO2 assisted machining

Novel “sub-zero” cooling methods are an emerging technology employed in machining of aerospace alloys that has been the focus of substantial ongoing research. A series of different cooling media have been used in an effort to decrease the friction and the amount of heat generated in the cutting zone. This study focused on the use of supercritical carbon dioxide (scCO2) as a coolant in the face milling of titanium alloy Ti-6Al-4V. Traditional flood emulsion coolant was compared with through tool scCO2 as well as scCO2 with minimum quantity lubrication (MQL)