SwePub - search: WFRF:(Ståhl Jan Eric)

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1.	Agic, Adnan, 1967- (author) Edge Geometry Effects on Entry Phase by Forces and Vibrations 2020 Doctoral thesis (other academic/artistic)abstract Intermittent machining is in general strongly related to the large impacts in the entry phase and related vibrations. The influence of the impact forces and vibrations on the cutting process is dependent on workpiece material, structural properties of the tool-workpiece system, cutting edge geometries and cutting parameters. Cutting forces adopt generally a periodic behaviour that gives rise to forced vibrations. In addition, self-induced vibrations may arise because of lowrigidity and insufficient damping in the tool-workpiece system at specific cutting parameters. The ability of the cutting tool to carry the loads during the entry phase and minimize the vibrations is often the key parameter for an effective machining operation.This research work is based on the experiments, analytical studies and modelling. It was carried out through six main studies beginning with a force build-up analysis of the cutting edge entry into the workpiece in intermittent turning. This was followed by a second study, concentrated on modelling of the entry phase which has partly been explored through experiments and theory developed in the first study.The third part was focused on the influence of the radial depth of cut upon the entry of the cutting edge into the workpiece in a face milling application. The methodology for the identification of unfavourable radial depth of cut is also addressed herein. Next, effects of the cutting edge on the vibrations in an end milling application were investigated. This study was related to a contouring operation with the maximum chip thickness in the entry phase when machining steel, ISO P material.The results of this work provide some general recommendations when milling this type of workpiece material. After that, the focus was set on the dynamic cutting forces in milling. The force developments over a tooth engagement in milling showed to be strongly dependent on the cutting edge geometry. A significant difference between highly positive versus highly negative geometry was found.The implication of this phenomena on the stress state in the cutting edge and some practical issues were analysed. Finally, the role of the helix angle on the dynamic response of a workpiece was investigated. The modelling technique using force simulation and computation of the dynamic response by means of modal analysis was presented. Extensive experimental work was conducted to compare the modelling and experimentally obtained results. The modelling results showed a similar trend as the experimental results. The influence of helix angle on the cutting forces and the dynamic response was explained in detail.The research conducted in this work contributes to the deeper understanding of the influence of the cutting edge geometry and the cutting parameters on the force build up process during the entry phase. The presented studies investigate the force magnitudes, force rates and dynamic behaviour of the tools and workpieces when machining at the challenging entry conditions. The methodologies applied are focused on the physical quantities as forces and vibrations rather than the experimental studies that evaluate tool life. The methods and results of the research work are of great interest for the design of the cutting tools and optimization of the cutting processes.
2.	Agmell, Mathias, et al. (author) Investigation of mechanical and thermal loads in pcBN tooling during machining of Inconel 718 2020 In: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 107, s. 1451-1462 Journal article (peer-reviewed)abstract This study investigates machining superalloy Inconel 718 with polycrystalline cubic boron nitride (pcBN) tooling both numerically and experimentally. Particular attention is given to mechanical and thermal stresses in the cutting tool arising from segmented chip formation and associated forces and temperatures. The temperature dependence of the mechanical properties of pcBN has been investigated and incorporated into a numerical model. In order to capture the dynamic loads due to a serrated chip formation, the Johnson–Cook damage model has been used. The extreme deformations during a machining process often results in a numerical difficulties due to a distorted elements. This paper uses the coupled Eulerian–Lagrangian (CEL) formulation in Abaqus/Explicit, where the workpiece is modelled with the Eulerian formulation and the cutting tool by the Lagrangian one. This CEL formulation enables to completely avoid mesh distortion. The finite element simulation results are validated via comparison of the modelled static and dynamic cutting forces and thermal loads induced into the cutting tool. The numerical model predicts a temperature of 1100–1200 ∘C at the cutting interface, which is in line with experimental determined data. The principal stresses at the rake up to 300 MPa are recorded, whereas higher level of stresses up to 450 MPa are found in the notch region of the tool, well correlated with experimental observation.
3.	Bello bermejo, Juan manuel, et al. (author) A Methodology Using Monte-Carlo Simulation on Nanoindentation Deconvolution for Metal Classification 2024 In: Proceedings of the 11th Swedish Production Symposium (SPS2024). - 2352-751X .- 2352-7528. - 9781643685106 - 9781643685113 ; 52, s. 613-627 Book chapter (peer-reviewed)abstract This paper investigates a methodology for the precise statistical deconvolution of hardness properties within various metallic matrix multiphase materials. The central focus is on accurately characterizing mechanical behaviour in the context of complex materials. To meet these objectives, we implemented an approach involving nanoindentation analyses of the selected materials. This technique allowed for the creation of material profiles based on micromechanical properties. Statistical cumulative density function (CDF) deconvolution was employed to disentangle the complex distributions of multiphase material hardness using cross-validation. Throughout the course of this study, several multicomponent CDF combinations were tested, including Weibull, Exponential, and Gaussian distributions. This approach challenges the conventional practice of assuming multiple Gaussian distributions of hardness, revealing the limitations of this approach. In addition, Monte-Carlo simulations were harnessed to generate probability density functions (PDFs) that capture the intricate footprint variations in hardness profiles. By implementing our methodology, we strive to offer a comprehensive and refined approach to materials analysis. This potential for differentiation has the significant implication of investigating the impact of impurities and trace elements on the mechanical properties and thus, machinability of metal materials. The ultimate aim is to enhance their recyclability, thereby advancing the principles of the circular economy and contributing to the sustainable development goals. Our study thus underscores the profound impact of material analysis on environmental sustainability and the efficient use of resources, while offering a fresh perspective on the role of statistics in materials science.
4.	Bjerke, Axel, et al. (author) Onset of the degradation of CVD alpha-Al2O3 coating during turning of Ca-treated steels 2021 In: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 477 Journal article (peer-reviewed)abstract The ability to control the shape, distribution and composition of non-metallic inclusions has had an important impact on many aspects of steel making. One such impact is on the machinability. Ca-treatments have shown to be able to reduce the abrasiveness of oxide inclusions, improve chip-breaking and lead to formation of deposits that reduce tool wear. However, machining Ca-treated steels with Al2O3 coated cemented carbide tools has not been as advantageous as expected. This study investigates the mechanisms behind the anomalous wear of Al2O3 coatings when turning soft Ca-treated steels. Longitudinal turning tests at a range of speeds (vc = 100-600 m/min) show rapid localized degradation of the Al2O3 coating limited to the sliding zone. Detailed analysis of the degradation mechanisms was performed using scanning and transmission electron microscopy. The results demonstrate a presence of chemical interactions between the alumina coating and non-metallic inclusions. The interaction resulted in the formation of mainly calcium aluminates and partly alumina-magnesia spinel. In-operando infrared thermography measurements indicate cutting temperatures of 850-1000 degrees C. Thermodynamic calculations give that CaO and MgO readily reacts with Al2O3, while the reaction with CaS requires presence of additional oxygen at these cutting conditions. Additional turning experiments investigate the influence of oxygen by controlling the cutting environment by adding oxygen (compressed air) or removing oxygen (supply argon). These additional tests show that the presence of additional oxygen has a limited impact on the possible Ca-Al2O3 interaction. This demonstrat a potential for further machinability improvements by controlling the chemical interaction between Ca and Mg based non-metallic inclusions and alumina coatings.
5.	Bushlya, Volodymyr, et al. (author) Effect of ageing on machining performance of grey cast iron and its compensation by cutting speed management 2024 In: CIRP Annals. - 0007-8506. Journal article (peer-reviewed)abstract Grey cast iron is known for its poor machinability directly after casting, but attains excellent machining performance after ageing. The present work explores the impact of cutting speed on the performance of pcBN machining for non-aged material. Findings suggest that tool wear can be minimized by identifying an optimal cutting speed that supports the formation of a stable Al2O3 and MnS build-up layer (BUL). Insufficient BUL protection accelerates pcBN wear by diffusion, while at very high speeds protective Al2O3 is replaced by weaker (Fe,Mn)2SiO4 and (Fe,Mn)O, and oxidation accelerates tool wear. The higher mechanical properties of aged GCI facilitate generation of high enough temperatures for stable deposition of Al2O3 BUL.
6.	Can, Antionette (creator_code:cre_t) Polycrystalline cubic boron nitride material 2023 Patent (other academic/artistic)abstract This disclosure relates to a polycrystalline cubic boron nitride, PCBN, material that includes a binder matrix material containing nitride compounds. The nitride compounds are selected from HfN, VN, and/or NbN.
7.	Hrechuk, Andrii, et al. (author) Novel metric “Implenarity” for characterization of shape and defectiveness : The case of CFRP hole quality 2021 In: Composite Structures. - : Elsevier BV. - 0263-8223. ; 265 Journal article (peer-reviewed)abstract Image Processing is rapidly expanding as a technique for object and defect analysis because of the high ease of its coupling to automation and IT solutions. Yet, issues with transferability of the measurement approaches and metrics currently used in mechanical systems often remain unsolved. Study reports on the developed approach for shape and defectiveness characterization by combining Delaunay triangulation of object's contour with uniformity analysis of triangles in the generated mesh using developed metric “Implenarity”. When analyzing hole drilling in CFRP, experimental validation found that for highest quality of CFRP holes, implenarity shifts from its maximum of I = 0.22 for a circle to I ≈ 0.16 for microdefects below 100 µm—normally not quantifiable with conventional techniques. In presence of larger hole defects, implenarity demonstrated similar capabilities to standard metrics, but avoided their inherent flaws. Implenarity continued distinguishing degree of defectiveness for the same area of uncut fibers (Fa-cov) and the same delamination diameter (Fd,Fda).
8.	Johansson, Jakob, et al. (author) On the function of lead (Pb) in machining brass alloys 2022 In: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 120:11-12, s. 7263-7275 Journal article (peer-reviewed)abstract Lead has traditionally been added to brass alloys to achieve high machinability, but the exact mechanisms at work are still debated. Lead-free brass alternatives could be developed if these mechanisms were better understood. Accordingly, machinability characteristics were investigated for two brass alloys with similar mechanical properties and phase composition, but with very different machining characteristics because one has 3 wt.% lead (CuZn38Pb3) while the other has only 0.1 wt.% (CuZn42). The effect of the lead was investigated using infrared temperature measurement, electron microscopy, secondary ion mass spectroscopy, quick-stop methods, and high-speed filming. Neither melting of lead nor its deposition on the tool rake surface takes place during machining thus confirming its limited lubrication and tribological effects. Instead, the main role of lead is to promote discontinuous chip formation. Lead deforms to flake-like shapes that act as crack initiation points when the workpiece material passes through the primary deformation zone. This effect prevents the development of stable tool–chip contact, thus lowering cutting forces, friction, and process temperature.
9.	Jönsson, Alexander, et al. (author) Strategies for Effective Chip Management in Machining of Ductile Cast Iron 2024 In: Proceedings of the 11th Swedish Production Symposium (SPS2024) : Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning - Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning. - 2352-751X .- 2352-7528. - 9781643685106 - 9781643685113 ; 52, s. 50-61 Conference paper (peer-reviewed)abstract A continuously growing and mutating market with increasing demands on environmental sustainability, illuminated by unraveling environmental threats, highlights the need for greater resource efficiency in modern manufacturing industries. Machining has become pivotal in the pursuit of sustainability given its superior efficiency in manufacturing of metallic products. In theory, the efficiency of a machining operation is dictated by the material removal rate and chip formation behavior. However, this may also present additional challenges as chips can be difficult to evacuate from the workpiece, and cause chip carryover. Chip management aims to contain manufacturing costs by addressing this issue and simultaneously pursuing higher machining efficiency. Persistent chips trapped in internal cavities is particularly challenging and can affect quality, and result in costly re-manufacturing, scrapping of portions of produced volume. Effective chip management strategies is therefore crucial to avoid these problems. While there is established research on machining theory and chip removal, proposed solutions are often focused on a specific implementation and lack a holistic perspective on the phenomenon. This study aims to fill this gap in the knowledge by providing a strategic and practical application to tie together information that would otherwise be disaggregated. A case study was conducted to investigate the role of machining, and identify the source of chip carryover and its effect on subsequent production stages. Practical verification demonstrated the effectiveness of the proposed interventions in reducing production costs by decreasing the cycle time and reducing waste, and improving product quality. The future of sustainable manufacturing processes relies on the adoption of strategies and interventions that contribute to the efficiency and sustainability of the manufacturing industry. This study provides a valuable contribution to this effort.
10.	Lindvall, Rebecka, et al. (author) Degradation of multi-layer CVD-coated cemented carbide in finish milling compacted graphite iron 2023 In: Wear. - : Elsevier BV. - 0043-1648. ; 522 Journal article (peer-reviewed)abstract Stricter regulations on emissions and higher demands on engine performance drive automotive industries to replace conventional gray cast iron with compacted graphite iron (CGI). CGI has a higher wear resistance, strength, elastic modulus, and almost double fatigue strength as to gray cast iron, yet the same positive properties make CGI more difficult to machine. This study focuses on finish milling CGI EN-GJV-450 with current industrial standard of tooling: cemented carbide with multi-layer CVD-coating of Ti(C,N)–Al2O3. At cutting speed of 150 m/min a total of 3126 cm3 of material after 190 passes was removed, while 1645 cm3 was removed after 100 passes in case of 250 m/min. Studying the wear evolution at different engagement times demonstrated an accelerated chemical wear of the Al2O3 top coating due to its reaction with MgO-containing inclusions that creates a softer reaction product of (Mg,Fe,Mn)Al2O4 spinel which is abraded and removed with the chip flow. Ti(C,N) coating layer experiences diffusional and mechanical (abrasion, debonding, micro-fracture) wear mechanisms. Exposure of cemented carbide substrate resulted in its rapid wear in the form of cratering and massive material loss on the flank where the latter eventually causes tool failure. The adherence of CGI to WC-Co facilitates diffusional loss of carbon and tungsten from WC grains. Carbon reacts with iron at the interface forming iron carbide, while residual tungsten alloys it thus forming (Fex,W1-x)3C. This phase can reduce the wear rate as it acts as a diffusion barrier, but its high brittleness enables its periodic removal by adhesive wear. Outward cobalt diffusion was also an active wear mechanism that facilitates further diffusion of carbon and tungsten but also weakens the WC-grain bonding, further facilitating adhesive wear by CGI flow. Deposition of oxide inclusions to exposed WC-Co work as an anti-stick for CGI adhesion and thus reduces the wear rate.
11.	Lindvall, Rebecka, et al. (author) Performance and wear mechanisms of PCD and pcBN cutting tools during machining titanium alloy Ti6Al4V 2020 In: Wear. - : Elsevier BV. - 0043-1648. ; 454-455 Journal article (peer-reviewed)abstract The need for increased productivity in difficult-to-machine titanium alloys has pushed manufacturers to examine the potential of ultrahard cutting tool materials such as polycrystalline diamond and polycrystalline cubic boron nitride as alternative solutions to conventional cemented carbide tools. This study examines the performance of such advanced tool materials in high speed finishing machining of Ti6Al4V, with attained PCD superiority compared to pcBN. Wear mechanisms are experimentally investigated based on in-depth microscopic analyses using techniques such as scanning electron microscopy, transmission electron microscopy, electron diffraction and X-ray energy-dispersive spectroscopy. Main wear morphologies were flank wear and cratering in both tool materials. Flank fracture caused by micro-cracking was an additional deterioration mechanism of pcBN tooling. Diamond burn-out, likely in combination with graphitization of diamond, was causing channel like wear morphology. The PCD wear mechanism was diffusion dissolution of carbon in Ti6Al4V. (Ti,V)C diffusional barrier or Tool Protection Layer (TPL) was formed due to reaction of workpiece and tool materials in presence of cobalt. Controlled grain size and increased cobalt content resulted in higher performance as protective caps of (Ti,V)C merged to form a continuous TPL. Similarly for pcBN, (Ti,V)B2 and (Ti,V,Cr)B2 reaction products acted as TPLs which reduced the tool deterioration rate.
12.	Lindvall, Rebecka, et al. (author) Performance and wear mechanisms of uncoated cemented carbide cutting tools in Ti6Al4V machining 2021 In: Wear. - : Elsevier BV. - 0043-1648. ; 477 Journal article (peer-reviewed)abstract The primary tool material when machining Ti6Al4V titanium alloy is uncoated straight cemented carbide. This study examines the performance of these materials during high-speed finish turning, and uses the advanced microscopy methods of SEM, (S)TEM, XEDS, and SAED to explore the fundamental tool wear mechanisms. The wear modes include a combination of flank wear and rake cratering. Four individual TEM lamellae were extracted from the crater and flank of one as-worn tool to investigate the wear mechanisms of cemented carbide exposed to different temperatures and contact conditions. The main wear mechanism identified is temperature-driven diffusion. Outward carbon diffusion occurs from surface WC grains into the adhered Ti alloy, which results in a layer of metallic tungsten. Dissolution of the W layer leads to doping of the α-Ti, thus causing its transformation into the β-Ti phase. At the same time, carbon-depleted WC grains interact with the Co binder, inducing formation of Co3W. Additional wear mechanisms include inward titanium diffusion, resulting in formation of TiC on both sides of the W layer. Simultaneously, TiCo2 is formed in Co-rich regions in the vicinity of the tool-chip interface. These reaction products retard direct dissolution of tool material in Ti6Al4V, thus acting as localized tool protection layers.
13.	Lindvall, Rebecka (creator_code:cre_t) Polycrystalline cubic boron nitride material 2023 Patent (other academic/artistic)abstract This disclosure relates to a high cBN content polycrystalline cubic boron nitride, PCBN, material. The binder matrix material comprises 19 to 50 wt. % chromium, or a compound thereof.
14.	Lindvall, Rebecka (creator_code:cre_t) Polycrystalline cubic boron nitride material 2023 Patent (other academic/artistic)abstract This disclosure relates to a high cBN content polycrystalline cubic boron nitride, PCBN, material. The binder matrix material comprises 2 to 15 wt.% titanium diboride (TiB2).
15.	Lindvall, Rebecka, et al. (author) Predicting wear mechanisms of ultra-hard tooling in machining Ti6Al4V by diffusion couples and simulation 2023 In: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 43:2, s. 291-303 Journal article (peer-reviewed)abstract Conventional cemented carbide is recommended for machining Ti6Al4V. However, polycrystalline diamond (PCD) and polycrystalline cubic boron nitride (pcBN) also show promise. Demands for higher productivity accelerate diffusional dissolution and chemically driven wear mechanisms in these tool materials. This study investigates active wear mechanisms by studying the interactions between Ti6Al4V and PCD, pcBN, and cemented carbide tools in diffusion couples at temperatures from 900° to 1300°C. All tool materials suffered from diffusion to varying degrees, and different chemical reactions occurred. Titanium carbide with minor vanadium alloying (Ti,V)C reaction products act as diffusion barriers when using PCD and cemented carbide, while the reaction products acting as diffusion barrier in pcBN is (Ti,V)B2. The presence of Mo and W in binder sites of pcBN reduces diffusional dissolution of cBN. Diffusion simulations agreed well with microscopy investigations and were enabled by the known temperature and pressure conditions of the static diffusion couples.
16.	Lindvall, Rebecka, et al. (author) Wear mechanisms in Ti(C,N)-Al2O3 coated carbide during sustainable machining CGI 2024 In: International Journal of Refractory Metals and Hard Materials. - : ELSEVIER SCI LTD. - 0263-4368. ; 119 Journal article (peer-reviewed)abstract By replacing conventional gray cast iron (GI) with compacted graphite iron (CGI), automotive industry could keep up with stricter regulations on emissions and demands on higher engine performance. CGI has improved properties as to GI but is more difficult to machine. This study evaluates sustainable machining performance during finish face milling when using minimum quantity lubrication applied vegetable oil, resulting in 8% or 17–23% improved tool life respectively as to dry conditions. The main part of the study investigates the wear mechanisms in commercial Ti(C,N)-Al2O3 CVD-coated cemented carbide. The coating degrades by mechanically induced cracking and fractures, oxidation of adhered CGI inside cracks, diffusional dissolution of Ti(C,N) layer. Formation of softer (Mg,Fe,Mn)Al2O4 spinel is not observed but could be an expected reaction product. Other oxide inclusions, when deposited on cemented carbide surfaces, prevents adhesion of CGI material, and can reduce the wear rate where they are present. CGI adhering to cemented carbide induces diffusional loss of cobalt and carbon that eventually forms (Fex,Co1-x)3C iron carbide at the tool-workpiece interface which can reduce the diffusion rate. Novel findings also relates to the formation of 15 μm deep cracks in the cemented carbide due to inward diffusion of Fe accompanied by its oxidation that speeds up the oxygen ingress and further oxidation of W and Co. Oxidation was found to provide a positive effect when the adhered CGI completely oxidized to form Fe2SiO4 oxide ceramic Tool Protection Layer which slowed down tool material degradation.
17.	Olsson, Mike, et al. (author) Cryogenic and hybrid induction-assisted machining strategies as alternatives for conventional machining of refractory tungsten and niobium 2021 In: International Journal of Refractory Metals and Hard Materials. - : Elsevier BV. - 0263-4368. ; 97 Journal article (peer-reviewed)abstract Tungsten (W) and niobium (Nb) belong to the refractory metal group and are used as alloying elements in steels and superalloys for high demand products. These metals are also used in a high purity single-phase state for products within nuclear, space, military and research facilities.In the current study, tool wear development and surface quality at different cutting conditions have been evaluated when machining high purity W 99.95% and Nb 99.7% in longitudinal turning. Cryogenic LN2 cooling and hybrid induction-assisted machining strategies were applied in order to alter W and Nb material state with respect to the ductile-to-brittle transformation temperature, and thus to attempt controlling their machinability. These advanced machining strategies were benchmarked against the more conventional machining solutions of dry, flood and high pressure cooling.It was found that the use of LN2 cooling demonstrated the best result in terms of tool life when machining W followed by induction-assisted heating, dry and flood. All machining strategies provided similar surface quality which is related to strong build-up edge formation and respective surface alteration. When machining Nb, high pressure coolant results in best performance in terms of tool life and surface quality, then followed by flood and cryogenic strategies. Overall, substantial improvement of surface quality (Ra = 0.4–0.6 μm) was observed for high cutting speeds vc ≥ 225 m/min.
18.	Olsson, Mike, et al. (author) Evaluation of tool wear mechanisms and tool performance in machining single-phase tungsten 2021 In: International Journal of Refractory Metals and Hard Materials. - : Elsevier BV. - 0263-4368. ; 94 Journal article (peer-reviewed)abstract Tungsten is commonly used in cemented carbide tooling solutions and as an alloying element in superalloys and steels. In pure form, as a single-phase tungsten, it is used in nuclear and research facilities. Tungsten is known for its poor machinability resulting in excessive tool wear, which puts high requirements on the selected tooling solution. Also, single-phase tungsten is a highly brittle material, thus often leading to surface damage when machining. In this study, eleven different tool materials: ceramics, coated and uncoated cemented carbide, cermet, PcBN and PCD have been tested in longitudinal turning of high purity tungsten (W > 99.9%) in order to identify suitable tool candidates. Seven cutting tool solutions consistently suffered from excessive tool wear or breakage after a few seconds of engagement time. Only two tool materials, PCD and PVD (TiAlN – TiSiN) coated cemented carbide provided sufficient performance. Analysis of their wear mechanisms with scanning and transmission electron microscopy revealed abrasion, oxidation and cracking of WC grains and diffusional dissolution of WC and Co in case of carbide tools. For PCD tools the main identified mechanisms are abrasion and diffusional dissolution. Cracking, formation of build-up edges, presence of workpiece porosity and W adhesion on the machined surface was found to be responsible for poor surface quality and sub-surface damage. Surface roughness for the PCD ranged within Ra = 1.3–1.7 μm and for the PVD coated carbide tool Ra = 1.0–1.5 μm.
19.	Olsson, Mike, et al. (author) Study of wear mechanisms of cemented carbide tools during machining of single-phase niobium 2020 In: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 450-451 Journal article (peer-reviewed)abstract In particle accelerator facilities, single-phase niobium is used in superconducting accelerator components. Machining induced surface quality of such components is strongly connected to the functionality of accelerators. In this study, tool wear development and its influence on the surface quality of Nb workpiece have been investigated in longitudinal turning. Uncoated cemented carbide cutting tools were used under finishing conditions (cutting speed vc = 300 m/min and feed f = 0.05 mm/rev) up to the wear criterion of VBmax = 300 μm. A detailed analysis of wear mechanisms of the cutting tool was conducted with help of high resolution electron microscopy (SEM and TEM). Further, the results obtained were correlated with controlled diffusion couples experiments under high pressure – high temperature conditions (2 GPa and 1000 °C). Diffusion of carbon from WC and formation of NbC was found to occur on the niobium – cemented carbide interface. Electron microscopy of the worn tools reports identical mechanisms of diffusion and chemical interaction which lead to rapid flank wear, yet formation of NbC on the rake completely inhibits tool degradation and thus acts as tool protection layer.
20.	Persson, Henrik, et al. (author) Performance and wear mechanisms of different PcBN tools when machining superalloy AD730 2022 In: Ceramics International. - : Elsevier BV. - 0272-8842. ; 48:16, s. 22733-22742 Journal article (peer-reviewed)abstract Nickel-based superalloys are known to be difficult to machine. These alloys are generally machined with cemented carbide tools under low productivity process conditions. Superhard polycrystalline cubic boron nitride (PcBN) tooling offers the possibility of increased production rates, however, a thorough understanding of the material performance and degradation is required before a transition from carbide tools occurs. This study investigated the performance and wear mechanism of three different PcBN tools with low (50 vol. %), medium (65 vol. %), and high (90 vol. %) cBN content, when turning AD730, a new Ni–Co-based superalloy. Due to the novelty of the material, little research has been done on its machinability with carbide and even less with PcBN tooling. The results showed the high-cBN grade was the best performer in terms of machining time. However, an undesirable wear morphology is generated, leading to excessively high cutting forces. Both the medium-cBN and low-cBN showed promise with stable rake and flank wear, but with notching as a drawback. Degradation analysis of medium-cBN grade revealed diffusional dissolution of cBN and formation of a reaction layer atop the cBN grains. The reaction layer, which acts as a diffusional barrier, consisted of three sub-layers: (1) Al2O3, (2) (Ti, Nb, Zr)N, and (3) (Ti, Cr, Nb, Zr)N. The low-cBN grade also showed a reaction layer; however, the smaller cBN grain size of this grade did not allow the layer to sufficiently stabilize.
21.	Persson, Henrik, et al. (author) Wear mechanisms of PcBN tools when machining AISI 316L 2021 In: Ceramics International. - : Elsevier BV. - 0272-8842. ; 47:22, s. 31894-31906 Journal article (peer-reviewed)abstract This paper investigates the machinability of AISI 316L stainless steel without and with NMI treatment, when machined with three different PcBN tool grades: low cBN content (50% vol.), medium (65% vol.) and high (90% vol.). The NMI treatment consisted of resulfurized and Ca-treated steels with two different Si/Al ratio. The tool materials were evaluated in terms of tool life, showing the best performance for the medium cBN content grade. Results showed that the crater wear has a more significant effect on the tool performance than the standard wear criteria of maximum flank wear. The worn tools were examined using scanning electron microscopy (SEM), focused ion beam (FIB) and transmission electron microscopy (TEM). In most cases, the crater exhibited three distinct regions from the edge to the end of the contact zone: the plateau, middle crater, and the upper region. Plateau and crater region displayed tool protective layer (TPL), consisting mostly of Al, Si, Mg and Ca-oxides; and some dimples in the tool from preferential wear of cBN grains. In the upper region of the best performing material, a ~1.5 μm thick TPL of mostly MnCr2O4 spinel was found, a result of the transfer of Mn- and Cr-rich oxide NMIs found in this material or oxidation of workpiece material, during the machining process.
22.	Rai, Chinthan, et al. (author) Additive Manufacturing Decision Support Systems : A Systematic Literature Review Discerning Current and Future Directions 2022 In: SPS 2022 - Proceedings of the 10th Swedish Production Symposium. - 2352-7528 .- 2352-751X. - 9781614994398 ; 21, s. 553-565 Conference paper (peer-reviewed)abstract Additive manufacturing (AM) was introduced the 1980's for rapid prototyping (RP) purposes but now AM provides complementary techniques to conventional manufacturing processes and offers advantages when components can be exacting, impossible, and too costly to be produced by conventional methods due to complex structures and geometric configurations, which require tailored designs. They are also often mass-customized components, with custom-made properties and low volume production requirements making AM the 'technology of choice' since its added-value aspects cannot be achieved by any other manufacturing technologies. These advancements in manufacturing, demand standardized fact-based decision support systems (DSSs), to support AM practitioners in their task selecting the most suitable techniques for given applications. Hence, this paper aims to increase the understanding of what - of how - DSSs are used in selecting and utilizing AM in various applications. This paper's core message, considering practical implications, is to guide and support AM researchers with an overview of the DSSs for AM landscape. This paper presents and compares different models and tools classified within four categories used as DSS for AM and identifies their advantages and disadvantages by conducting a 3-step systematic literature review (SLR). A total of 388 literatures were initially retrieved, and according to an inclusion criteria analysis, the literatures were evaluated. This is the first SLR emphasizing and synthesizing obtainable literatures on AM DSS. Until now, this topic has acquired narrow exploration; however, the authors believe it is of rapidly growing importance to both scientists and practitioners.
23.	Sirtuli, Larissa Juliana, et al. (author) Machining of Compacted Graphite Iron : A review 2024 In: Journal of Materials Processing Technology. - 0924-0136. ; 332 Research review (peer-reviewed)abstract Compacted Graphite Iron (CGI) represents a unique combination of the characteristics of grey and spheroidal cast irons, sparking significant interest over the past two decades, particularly as a favoured material in several automotive industry applications, including engine components and heavy-duty vehicle parts. Despite its growing prominence, the full potential of CGI remains underutilised, primarily due to its lower productivity rate compared to grey cast iron. This paper comprehensively reviews existing research on CGI machining, emphasising the challenges and exploring opportunities for development in this field. A detailed comparison between the machining of compacted graphite iron, grey cast iron and spheroidal graphite cast iron is provided, highlighting the unique characteristics associated with CGI. The influence of microstructure and chemical composition on machining processes is thoroughly examined and deliberated. Moreover, this review delves into the effects of various process variables on CGI machining, including cutting tools, lubrication, and cooling methods. The paper concludes by discussing potential future trends and innovations in CGI machining, offering a prospective outlook on how these developments could bridge the productivity and literature gap and enhance the utilisation of CGI in industrial applications.
24.	Slipchenko, Kateryna, et al. (author) CBN-based cutting tools with niobium compounds as a binder phase 2020 In: 9th CIRP Conference on High Performance Cutting, HPC 2020. - : Elsevier BV. - 2212-8271. - 9781713835431 ; 101, s. 254-257 Conference paper (peer-reviewed)abstract cBN-based materials are well known for their high chemical inertness and high performance. The variation of binder phase type and amount enable improvement of performance even more. Comprehensive investigation of the influence of type of niobium compound (NbC and NbN) as a binder phase for cBN-based materials were done. Samples were prepared by high pressure high temperature (HPHT) sintering under pressure of 7.7 GPa. Sintered samples were investigated in terms of phase composition (XRD), microstructure (SEM, EDX) and mechanical properties. Performance of investigated tools were tested in conditions of high speed machining of Inconel 718 alloy and Caldie tool steel.
25.	Slipchenko, Kateryna, et al. (author) Multicomponent binders for PcBN performance enhancement in cutting tool applications 2022 In: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219. ; 42:11, s. 4513-4527 Journal article (peer-reviewed)abstract This study proposes a novel design of binders for polycrystalline cubic boron nitride (PcBN) cutting tool materials. Well-known binder phases TiC and TiN were combined with transitional metal nitrides ZrN, VN, and HfN. Performance screenings of longitudinal turning Inconel 718 and AISI 316 L highlighted the superior performance of PcBN materials with mixed TiC-ZrN and TiC-VN binders. These two systems were further sintered in a wider range of temperatures. XRD and STEM-XEDS analysis confirmed mutual dissolution of both TiC and ZrN, and TiC and VN, thus forming two types of solid solutions (Ti,Zr)(C,N) and (Ti,V)(C,N). Extended performance tests showed that tools with TiC-ZrN binder outperform reference PcBN with TiC binder by up to 20% when machining Inconel 718. When machining hardened Caldie tool steel, the performance of tools with TiC-ZrN and TiC-VN binders were 80–90% higher than the reference tools.
26.	Ståhl, Jan Eric, et al. (author) A Concept from Sensor to Sustainability in Machining - An Interdisciplinary Approach over a Wide TRL Range 2024 In: Proceedings of the 11th Swedish Production Symposium (SPS2024) : Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning - Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning. - 2352-751X .- 2352-7528. - 9781643685106 - 9781643685113 ; 52, s. 148-170 Conference paper (peer-reviewed)abstract This publication describes a concept that intends to enable an optimization of machining with regard to the balance between criteria related to technology, economy and sustainability. The work is of a discussion nature and intends to provide a framework for further research and development in the area. Previous research and development during the 80's and 90's is presented in general terms and in particular the reasons for its limited success in providing real-time feedback on machining operations are highlighted, despite very large financial investments even by today's standards. Ongoing research worldwide in current process optimization and its associated building blocks will be highlighted, and identified important work is referenced. Below are new conditions that can be linked to both process knowledge and its modeling, as well as new conditions for developing integrated sensors that can handle the extreme environment in and around a processing operation. A previous limiting factor has been signal processing and signal transmission, which with new knowledge and developed technology in the last 10 years provides new conditions for process optimization in real time.The need for new and up-to-date principles for process optimization, which also integrate sustainability issues and environmental impact, has increased in importance in several respects. Important issues such as tool utilization, efficient use of materials and high time utilization have become relevant as these process results control both energy consumption and environmental impact. The geopolitical development linked to the availability of critical tool materials such as cobalt and tungsten also drives research issues that can generally optimize and streamline production processes.Finally, the publication describes the possibility of realizing a real-time feedback and optimized machining that takes into account technology, economy and sustainability, through interdisciplinary research across several levels of technology readiness (TRL). The results are expected to have positive effects on several production factors before, during and after machining. Developed technologies in machining can also make valuable contributions to the development of other products and production processes.
27.	Ståhl, Jan Eric, et al. (author) Key Performance Index for Creating an Integrated and Sustainable Academy - A University with the Ability to Meet Future Needs and Challenges Identified in Society and Industry 2024 In: Moving Integrated Product Development to Service Clouds in the Global Economy - Proceedings of the 21st ISPE Inc. International Conference on Concurrent Engineering, CE 2014. - 2352-7528 .- 2352-751X. - 9781643685113 - 9781643685106 ; 52, s. 643-659 Conference paper (peer-reviewed)abstract Key performance indexes (KPIs) in various forms have always been used in one way or another in the production and processing of raw materials. The need for KPIs was accentuated with the advent of industrialism in the western world. The way and strategy of manufacturing industrial products has been divided into several so-called developmental transformations. Primarily after the depression of the 1930s and after the Second World War, a way of working and a basic view was gradually created that has resource efficiency and goal achievement as a fundamental idea. This publication describes how KPIs can be used in higher education to create a sustainable academy to meet challenges in industry and society over time. This with a focus on sustainability and continuity as well as a strategic integration between the academy's various missions. These missions consist of teaching, research and collaboration. Furthermore, according to the Higher Education Ordinance, teaching shall rest on a scientific basis and, when appointing senior positions, equal weight shall be attached to the merits that can be linked to teaching and research. In addition to teaching and research, collaboration must be conducted with the surrounding society. Society places increasing demands on the knowledge conveyed in teaching to harmonize with current needs and to prepare for future needs and challenges. A starting point for the publication is that needs and challenges can best be met through a conscious and strategic integration between the academy's various missions. Another aspect that is highlighted in this publication is the importance of strengthening the collaboration between basic subjects and more applied and industry-related subjects, which provides renewal in the applied subjects at the same time as the basic research can be utilized at a higher rate. In an industrial perspective, a more continuous TRL scale is obtained, which provides a more effective implementation of research results. A development path that strengthens the Academy's mission areas is the principle of affiliation of personnel from industry and other sectors of society and increased admission of industrial doctoral students and other external doctoral students. In order to monitor the development of the respective mission areas of academia and its integration, the use of KPIs will be addressed. A discussion of their benefits will be highlighted but also the associated difficulties, especially when conditions change. The conducted literature study shows that there are very few or rather no found publications dealing with KPIs for the integration of the Academy's different missions. KPIs are well developed for higher education in terms of its implementation and associated economics. Corresponding published work related to KPIs in research deals primarily with conventional academic bibliometrics.
28.	Ståhl, Jan Eric, et al. (author) Relationship Between Tool Temperature Distribution and Stagnation Point Behavior for Different Process Factors in Machining Operations 2024 In: Moving Integrated Product Development to Service Clouds in the Global Economy - Proceedings of the 21st ISPE Inc. International Conference on Concurrent Engineering, CE 2014. - 2352-751X .- 2352-7528. - 9781643685106 ; 52, s. 69-89 Conference paper (peer-reviewed)abstract Metal cutting is physically defined by a tool separating a chip by developing a stagnation point after the work material has passed a shear plane. This distinguishes the method group metal cutting or machining from shearing and wedging processes. The development of the stagnation point is central to the functioning of a metal cutting process. The stagnation point and its behavior has a great influence on the different load conditions of the tool as it controls both the temperature distribution and the mechanical load distribution around the tool's edge-line. This publication shows that there is a temperature drop at the stagnation point where the shear stress changes sign, which means that the shear stress at this point assumes the value zero. Furthermore, it is demonstrated that there is a correlation between the position of the temperature dip, its size and the selected cutting data as well as tool geometry and current work material. The knowledge of the interaction between the position of the stagnation point and the tool coating type in combination with the tool's micro- and macro-geometry will be of importance for the development of high-performance tools optimized for different machining applications.
29.	Weng, Jian, et al. (author) A machine learning based approach for determining the stress-strain relation of grey cast iron from nanoindentation 2020 In: Mechanics of Materials. - : Elsevier BV. - 0167-6636. ; 148 Journal article (peer-reviewed)abstract Apart from microhardness and elastic modulus, the stress-strain relation is another important characteristic that more and more scholars have been trying to extract from nanoindentation. With the development of artificial intelligence and computer technology, a machine learning based method is proposed in this paper to extract stress-strain curve of grey cast iron using sharp nanoindentation. Firstly, the average curve is achieved by the grid-design nanoindentation to avoid the influence of different phases on indentation results. The plastic behavior is considered as a power law function in this paper. Then, finite element method supports to generate a simulation data set, with full-factor and full-level design of constants of stress-strain relation. With the simulation data set, the support vector regression machine establishes a surrogate model to correlate the input (constants of stress-strain function) and output (the mean error between predicted and measured results). The best parameters of support vector machine are determined through grid search and cross-validation. PSO serves as the optimization algorithm to find the optimum of input related to the measured results, with an inertia factor to improve the local search ability. Finally, the simulation loading curve with the optimal constants provided by PSO perfectly fits the measured loading curve, which shows the effectiveness of the inverse method proposed in this paper.

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