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A. Klink
Laboratory for Machine Tools and Production Engineering (WZL), RWTH Aachen University, 52062 Aachen, Germany

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Journal article
Published: 10 July 2021 in Metals
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The surface and subsurface conditions of components are critical for their functional properties. Every manufacturing process modifies the surface condition as a consequence of its mechanical, chemical, and thermal impact or combinations of the three. The depth of the affected zone varies for different machining operations and is related to the process parameters and characteristics. Furthermore, the initial material state has a decisive influence on the modifications that lead to the final surface conditions. With this knowledge, the collaborative research center CRC/Transregio 136 “Process Signatures” started a first joint investigation to analyze the influence of several machining operations on the surface modifications of uniformly premanufactured samples in a broad study. The present paper focusses on four defined process chains which were analyzed in detail regarding the resulting surface conditions as a function of the initial state. Two different workpiece geometries of the same initial material (AISI 4140, 42CrMo4 (1.7225) classified according to DIN EN ISO 683-2) were treated in two different heat treating lines. Samples annealed to a ferritic-perlitic microstructure were additionally deep rolled as starting condition. Quenched and tempered samples were induction hardened before further process application. These two states were then submitted to six different manufacturing processes, i.e., grinding (with mainly mechanical or thermal impact), precision turning (mainly mechanical), laser processing (mainly thermal), electrical discharge machining (EDM, mainly thermal) and electrochemical machining (ECM, (mainly chemical impact). The resulting surface conditions were investigated after each step of the manufacturing chain by specialized analysis techniques regarding residual stresses, microstructure, and hardness distribution. Based on the process knowledge and on the systematic characterizations, the characteristics and depths of the material modifications, as well as their underlying mechanisms and causes, were investigated. Mechanisms occurring within AISI 4140 steel (42CrMo4) due to thermal, mechanical or mixed impacts were identified as work hardening, stress relief, recrystallization, re-hardening and melting, grain growth, and rearrangement of dislocations.

ACS Style

Florian Borchers; Brigitte Clausen; Lisa Ehle; Marco Eich; Jérémy Epp; Friedhelm Frerichs; Matthias Hettig; Andreas Klink; Ewald Kohls; Yang Lu; Heiner Meyer; Bob Rommes; Sebastian Schneider; Rebecca Strunk; Tjarden Zielinski. The Influence of Former Process Steps on Changes in Hardness, Lattice and Micro Structure of AISI 4140 Due to Manufacturing Processes. Metals 2021, 11, 1102 .

AMA Style

Florian Borchers, Brigitte Clausen, Lisa Ehle, Marco Eich, Jérémy Epp, Friedhelm Frerichs, Matthias Hettig, Andreas Klink, Ewald Kohls, Yang Lu, Heiner Meyer, Bob Rommes, Sebastian Schneider, Rebecca Strunk, Tjarden Zielinski. The Influence of Former Process Steps on Changes in Hardness, Lattice and Micro Structure of AISI 4140 Due to Manufacturing Processes. Metals. 2021; 11 (7):1102.

Chicago/Turabian Style

Florian Borchers; Brigitte Clausen; Lisa Ehle; Marco Eich; Jérémy Epp; Friedhelm Frerichs; Matthias Hettig; Andreas Klink; Ewald Kohls; Yang Lu; Heiner Meyer; Bob Rommes; Sebastian Schneider; Rebecca Strunk; Tjarden Zielinski. 2021. "The Influence of Former Process Steps on Changes in Hardness, Lattice and Micro Structure of AISI 4140 Due to Manufacturing Processes." Metals 11, no. 7: 1102.

Journal article
Published: 22 April 2021 in Materials
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The electrochemical machining (ECM) of 42CrMo4 steel in sodium nitrate solution is mechanistically characterized by transpassive material dissolution and the formation of a Fe3−xO4 mixed oxide at the surface. It is assumed that the efficiency of material removal during ECM depends on the structure and composition of this oxide layer as well as on the microstructure of the material. Therefore, 42CrMo4 in different microstructures (ferritic–pearlitic and martensitic) was subjected to two ECM processes with current densities of about 20 A/cm2 and 34 A/cm2, respectively. The composition of the process electrolyte was analyzed via mass spectrometry with inductively coupled plasma in order to obtain information on the efficiency of material removal and the reaction mechanisms. This was followed by an X-ray photoelectron spectroscopy analysis to detect the chemical composition and the binding states of chemical elements in the oxide formed during ECM. In summary, it has been demonstrated that the efficiency of material removal in both ECM processes is about 5–10% higher for martensitic 42CrMo4 than for ferritic–pearlitic 42CrMo4. This is on one hand attributed to the presence of the cementite phase at ferritic–pearlitic 42CrMo4, which promotes oxygen evolution and therefore has a negative effect on the material removal efficiency. On the other hand, it is assumed that an increasing proportion of Fe2O3 in the mixed oxide leads to an increase in the process efficiency.

ACS Style

Alexander Schupp; Oliver Beyss; Bob Rommes; Andreas Klink; Daniela Zander. Insights on the Influence of Surface Chemistry and Rim Zone Microstructure of 42CrMo4 on the Efficiency of ECM. Materials 2021, 14, 2132 .

AMA Style

Alexander Schupp, Oliver Beyss, Bob Rommes, Andreas Klink, Daniela Zander. Insights on the Influence of Surface Chemistry and Rim Zone Microstructure of 42CrMo4 on the Efficiency of ECM. Materials. 2021; 14 (9):2132.

Chicago/Turabian Style

Alexander Schupp; Oliver Beyss; Bob Rommes; Andreas Klink; Daniela Zander. 2021. "Insights on the Influence of Surface Chemistry and Rim Zone Microstructure of 42CrMo4 on the Efficiency of ECM." Materials 14, no. 9: 2132.

Journal article
Published: 15 January 2021 in Materials
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The efficiency of material removal by electrochemical machining (ECM) and rim zone modifications is highly dependent on material composition, the chemical surface condition at the break through potential, the electrolyte, the machining parameters and the resulting current densities and local current density distribution at the surfaces. The ECM process is mechanistically determined by transpassive anodic metal dissolution and layer formation at high voltages and specific electrolytic compositions. The mechanisms of transpassive anodic metal dissolution and oxide formation are not fully understood yet for steels such as 42CrMo4. Therefore, martensitic 42CrMo4 was subjected to ECM in sodium nitrate solution with two different current densities and compared to the native oxide of ground 42CrMo4. The material removal rate as well as anodic dissolution and transpassive oxide formation were investigated by mass spectroscopic analysis (ICP-MS) and (angle-resolved) X-ray photoelectron spectroscopy ((AR)XPS) after ECM. The results revealed the formation of a Fe3−xO4 mixed oxide and a change of the oxidation state for iron, chromium and molybdenum, e.g., 25% Fe (II) was present in the oxide at 20.6 A/cm2 and was substituted by Fe (III) at 34.0 A/cm2 to an amount of 10% Fe (II). Furthermore, ECM processing of 42CrMo4 in sodium nitrate solution was strongly determined by a stationary process with two parallel running steps: 1. Transpassive Fe3−xO4 mixed oxide formation/repassivation; as well as 2. dissolution of the transpassive oxide at the metal surface.

ACS Style

Daniela Zander; Alexander Schupp; Oliver Beyss; Bob Rommes; Andreas Klink. Oxide Formation during Transpassive Material Removal of Martensitic 42CrMo4 Steel by Electrochemical Machining. Materials 2021, 14, 402 .

AMA Style

Daniela Zander, Alexander Schupp, Oliver Beyss, Bob Rommes, Andreas Klink. Oxide Formation during Transpassive Material Removal of Martensitic 42CrMo4 Steel by Electrochemical Machining. Materials. 2021; 14 (2):402.

Chicago/Turabian Style

Daniela Zander; Alexander Schupp; Oliver Beyss; Bob Rommes; Andreas Klink. 2021. "Oxide Formation during Transpassive Material Removal of Martensitic 42CrMo4 Steel by Electrochemical Machining." Materials 14, no. 2: 402.

Journal article
Published: 25 August 2020 in Journal of Engineering for Gas Turbines and Power
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The demand for higher efficiency in aircraft propulsion engines leads to materials with increasing thermomechanical strengths and new designs inducing filigree geometries of blisks and disks. Because of new designs which induce tighter tolerances, the high mechanical process forces in conventional cutting processes like broaching cause inacceptable geometrical deviations and high tooling costs. Due to the electro-thermal material removal mechanism, electrical discharge machining (EDM) ensures a force free and thus precise machining. The manufacture of fir tree slots in nickel-based alloys by wire EDM has been investigated in the last few years and the process was verified as an alternative technology for broaching. To get a better competitive position, the productivity can be prospectively increased by using an additional indexing rotary axis which ensures a precise and automated production of rotationally symmetric components and reduce production times, e.g., for the manufacture of fir tree slots on a disk. Nevertheless, the application of these axes cause changed flushing conditions and can also affect the electrical contacting as well. Both influence the process performance and demand a technology development or adjustment of standard machining technologies. The influence of these changed machining conditions has not been investigated scientifically to date. In this paper, the surface integrity and process performance of fir tree slots machined by wire EDM on the machine table are compared with the manufacture by using an additional indexing rotary axis.

ACS Style

Thomas Bergs; Ugur Tombul; Tim Herrig; Andreas Klink; David Welling. Influence of an Additional Indexing Rotary Axis on Wire Electrical Discharge Machining Performance for the Automated Manufacture of Fir Tree Slots. Journal of Engineering for Gas Turbines and Power 2020, 142, 1 .

AMA Style

Thomas Bergs, Ugur Tombul, Tim Herrig, Andreas Klink, David Welling. Influence of an Additional Indexing Rotary Axis on Wire Electrical Discharge Machining Performance for the Automated Manufacture of Fir Tree Slots. Journal of Engineering for Gas Turbines and Power. 2020; 142 (9):1.

Chicago/Turabian Style

Thomas Bergs; Ugur Tombul; Tim Herrig; Andreas Klink; David Welling. 2020. "Influence of an Additional Indexing Rotary Axis on Wire Electrical Discharge Machining Performance for the Automated Manufacture of Fir Tree Slots." Journal of Engineering for Gas Turbines and Power 142, no. 9: 1.

Journal article
Published: 05 July 2020 in Metals
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The surface and subsurface conditions of components are significant for their functional properties. Every manufacturing process step changes the surface condition due to its mechanical, chemical and/or thermal impact. The depth of the affected zone varies for different machining operations, and is predetermined by the process parameters and characteristics. Furthermore, the initial state has a decisive influence on the interactions that lead to the final surface conditions. The aim of the investigation presented here is to compare the influence of the load characteristics over the depth applied to manufactured components by several different machining operations and to determine the causing mechanisms. In order to ensure better comparability between the surface modifications caused by different machining operations, the same material was used (AISI 4140; German steel grade 42CrMo4 acc. to DIN EN 10083-3) and annealed to a ferritic-pearlitic microstructure. Based on interdisciplinary cooperation within the collaborative research center CRC/Transregio 136 “Process Signatures”, seven different manufacturing processes, i.e., grinding, turning, deep rolling, laser processing, inductive heat treatment, electrical discharge machining (EDM) and electrochemical machining (ECM), were used, and the resulting surface zones were investigated by highly specialized analysis techniques. This work presents the results of X-ray measurements, hardness measurements and electron microscopic investigations. As a result, the characteristics and depths of the material modifications, as well as their underlying mechanisms and causes, were studied. Mechanisms occurring within 42CrMo4 steel due to thermal, mechanical, chemical or mixed impacts were identified as phase transformation, solidification and strengthening due to dislocation generation and accumulation, continuum dynamic recrystallization and dynamic recovery, as well as chemical reactions.

ACS Style

Florian Borchers; Brigitte Clausen; Sandro Eckert; Lisa Ehle; Jeremy Epp; Simon Harst; Matthias Hettig; Andreas Klink; Ewald Kohls; Heiner Meyer; Markus Meurer; Bob Rommes; Sebastian Schneider; Rebecca Strunk. Comparison of Different Manufacturing Processes of AISI 4140 Steel with Regard to Surface Modification and Its Influencing Depth. Metals 2020, 10, 895 .

AMA Style

Florian Borchers, Brigitte Clausen, Sandro Eckert, Lisa Ehle, Jeremy Epp, Simon Harst, Matthias Hettig, Andreas Klink, Ewald Kohls, Heiner Meyer, Markus Meurer, Bob Rommes, Sebastian Schneider, Rebecca Strunk. Comparison of Different Manufacturing Processes of AISI 4140 Steel with Regard to Surface Modification and Its Influencing Depth. Metals. 2020; 10 (7):895.

Chicago/Turabian Style

Florian Borchers; Brigitte Clausen; Sandro Eckert; Lisa Ehle; Jeremy Epp; Simon Harst; Matthias Hettig; Andreas Klink; Ewald Kohls; Heiner Meyer; Markus Meurer; Bob Rommes; Sebastian Schneider; Rebecca Strunk. 2020. "Comparison of Different Manufacturing Processes of AISI 4140 Steel with Regard to Surface Modification and Its Influencing Depth." Metals 10, no. 7: 895.

Journal article
Published: 21 May 2020 in CIRP Annals
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Modelling of ECM is a powerful tool to improve the cost- and time intensive tool-development process. However, for certain combinations of process and geometric parameters, the simulation results include non-physical negative pressure values inside the electrolyte flow. These phenomena occur near the narrow opening into the machining gap. According to Bernoulli's law, it is plausible that low-pressure values are present in this region possibly leading to evaporation. Based on these facts, it was hypothesized that cavitation could occur during ECM. In order to successfully validate this hypothesis, the electrolyte flow is analysed both in experimental as well as simulation-based studies.

ACS Style

A. Klink; L. Heidemanns; B. Rommes. Study of the electrolyte flow at narrow openings during electrochemical machining. CIRP Annals 2020, 69, 157 -160.

AMA Style

A. Klink, L. Heidemanns, B. Rommes. Study of the electrolyte flow at narrow openings during electrochemical machining. CIRP Annals. 2020; 69 (1):157-160.

Chicago/Turabian Style

A. Klink; L. Heidemanns; B. Rommes. 2020. "Study of the electrolyte flow at narrow openings during electrochemical machining." CIRP Annals 69, no. 1: 157-160.

Journal article
Published: 01 January 2020 in Procedia CIRP
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The thermal, mechanical and chemical stability of a material can theoretically be estimated by the Gibbs free energy of formation. Based on this, a new class of alloys – High Entropy Alloys (HEAs) – was designed in the past two decades, maximizing the entropy for a minimum free energy and consequently outstanding material properties. However, the machinability by conventional cutting is limited due to the increased stability. Therefore, electrical discharge machining (EDM) as well as electrochemical machining (ECM) are investigated as alternatives. This includes the fundamental analysis of surface morphology as well as resulting subsurface properties for two state-of-the-art second generation HEAs.

ACS Style

Andreas Klink; Simon Harst; Marcel Olivier; Ugur Tombul; Thomas Bergs. High Entropy Alloy machining by EDM and ECM. Procedia CIRP 2020, 95, 178 -182.

AMA Style

Andreas Klink, Simon Harst, Marcel Olivier, Ugur Tombul, Thomas Bergs. High Entropy Alloy machining by EDM and ECM. Procedia CIRP. 2020; 95 ():178-182.

Chicago/Turabian Style

Andreas Klink; Simon Harst; Marcel Olivier; Ugur Tombul; Thomas Bergs. 2020. "High Entropy Alloy machining by EDM and ECM." Procedia CIRP 95, no. : 178-182.

Journal article
Published: 01 January 2020 in Procedia CIRP
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The microstructure evolution induced in the workpiece during a manufacturing process influences the functionality of the final product. Therefore, there is a high interest for prediction of the induced microstructure evolution in surface and sub-surface layers of the workpiece. Up to the present day, determination of the final state of microstructure is mostly based on the personal experience obtained from numerous experiments. The microstructure evolution simulation is an alternative to the old trial and error approaches. The recent developments in the computational capacity lead to considerable advances in the material simulation science. In the previous years the authors of this work used the phase field approach for modeling of the microstructure evolution in a steel workpiece under thermal cycle with high temperature gradients. As follow up to the previous works, the presented model is modified to be adjustable for real microstructure of material as well as considerably higher temperature gradients. This model can further be used for modeling of the microstructure evolution during processes with main thermal impact. To evaluate the phase field model, the results of simulations were compared with the experimental data.

ACS Style

T. Bergs; M. Mohammadnejad; R. Hess; L. Heidemanns; A. Klink. Simulation of the Evolutions in Real Microstructure of Material under Thermal Cycle with High Thermal Gradients. Procedia CIRP 2020, 95, 238 -243.

AMA Style

T. Bergs, M. Mohammadnejad, R. Hess, L. Heidemanns, A. Klink. Simulation of the Evolutions in Real Microstructure of Material under Thermal Cycle with High Thermal Gradients. Procedia CIRP. 2020; 95 ():238-243.

Chicago/Turabian Style

T. Bergs; M. Mohammadnejad; R. Hess; L. Heidemanns; A. Klink. 2020. "Simulation of the Evolutions in Real Microstructure of Material under Thermal Cycle with High Thermal Gradients." Procedia CIRP 95, no. : 238-243.

Book chapter
Published: 05 June 2019 in CIRP Encyclopedia of Production Engineering
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ACS Style

Andreas Klink. Electric Discharge Machining. CIRP Encyclopedia of Production Engineering 2019, 555 -559.

AMA Style

Andreas Klink. Electric Discharge Machining. CIRP Encyclopedia of Production Engineering. 2019; ():555-559.

Chicago/Turabian Style

Andreas Klink. 2019. "Electric Discharge Machining." CIRP Encyclopedia of Production Engineering , no. : 555-559.

Journal article
Published: 29 April 2019 in CIRP Annals
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For the successful implementation of bio-degradable magnesium implants in medicine, a defined corrosion behaviour according to the bone growth needs to be established. While conventional concepts focus on a defined adaptation of the base alloy composition, the presented approach focusses on a defined macro- and microstructuring of the implant. This includes both, a defined surface enlargement and conversion by surface modificaiton as well as the realization of inner channels for ingrowth. This is achieved by a process combination of plasma electrolytic oxidation (PEO) and electrical discharge machining (EDM). Resulting surface characteristics as well as in-vitro and in-vivo degradation behaviour have been comprehensively analyzed.

ACS Style

Alexander Kopp; Ralf Smeets; Ole Jung; Nadja Kröger; Andreas Klink. Defined surface adjustment for medical magnesium implants by electrical discharge machining (EDM) and plasma electrolytic oxidation (PEO). CIRP Annals 2019, 68, 583 -586.

AMA Style

Alexander Kopp, Ralf Smeets, Ole Jung, Nadja Kröger, Andreas Klink. Defined surface adjustment for medical magnesium implants by electrical discharge machining (EDM) and plasma electrolytic oxidation (PEO). CIRP Annals. 2019; 68 (1):583-586.

Chicago/Turabian Style

Alexander Kopp; Ralf Smeets; Ole Jung; Nadja Kröger; Andreas Klink. 2019. "Defined surface adjustment for medical magnesium implants by electrical discharge machining (EDM) and plasma electrolytic oxidation (PEO)." CIRP Annals 68, no. 1: 583-586.

Journal article
Published: 13 December 2018 in Procedia Manufacturing
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The demand for higher efficiency in aircraft propulsion engines leads to materials with increasing thermo-mechanical strengths. The high mechanical process forces in conventional cutting processes cause inacceptable geometrical deviations. Due to the electro-thermal material removal mechanism, wire electrical discharge machining (EDM) is a promising alternative manufacturing process. The manufacturing process is not restricted to thermo-mechanical properties (e.g. hardness or high-temperature strength). However, it is necessary to increase productivity to get a better competitive position. Unstable process conditions limit the productivity of the wire EDM process and the quality of the workpieces. These process conditions are characterized by misdischarges and short discharges, which lead to undesirable changes of material properties and thus to wire breakages. Moreover, a wire breakage interrupts the wire EDM process and extends the machining time. Therefore, this paper deals with the analysis of characteristic parameters to identify unstable process conditions during wire EDM. For that purpose, the differences between characteristic parameters of a stable and unstable wire EDM process are investigated. Furthermore, the distribution of the different types of discharges are analyzed. Results of the investigations are supposed to provide a basis for early detection of possible wire breakages and thus an adaption of control algorithm. Therefore, a stable and an automatable manufacturing process can be achieved and increase the productivity especially when machining relevant turbomachinery parts like fir tree slots in disks.

ACS Style

T. Bergs; U. Tombul; T. Herrig; M. Olivier; A. Klink; F. Klocke. Analysis of Characteristic Process Parameters to Identify Unstable Process Conditions during Wire EDM. Procedia Manufacturing 2018, 18, 138 -145.

AMA Style

T. Bergs, U. Tombul, T. Herrig, M. Olivier, A. Klink, F. Klocke. Analysis of Characteristic Process Parameters to Identify Unstable Process Conditions during Wire EDM. Procedia Manufacturing. 2018; 18 ():138-145.

Chicago/Turabian Style

T. Bergs; U. Tombul; T. Herrig; M. Olivier; A. Klink; F. Klocke. 2018. "Analysis of Characteristic Process Parameters to Identify Unstable Process Conditions during Wire EDM." Procedia Manufacturing 18, no. : 138-145.

Journal article
Published: 13 December 2018 in Procedia Manufacturing
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Due to the continuous enhancements not only of aero engines, novel materials with higher hardness and high-temperature strength are nowadays often applied. The specific material properties limit the economic machining by conventional manufacturing processes while wire electrical discharge machining (EDM) ensures it. In addition, wire EDM is increasingly used to manufacture complex shapes e.g. rotationally symmetric components. For this purpose, multi axes machining is necessary to automate the manufacture. Due to the changed electrical contacting and flushing conditions by using such additional axes, an adaption of the technology is necessary. The development or adaption of a wire EDM technology are a big effort and time consuming. To simplify the adjustment of wire EDM technologies when using an additional axis, the influence of selected process parameters on the process performance is analyzed. The results of the investigations are supposed to serve as a reference for technology adaptions.

ACS Style

T. Bergs; U. Tombul; T. Herrig; A. Klink; F. Klocke. Experimental Analysis of Influence of Discharge Current, Pulse Interval Time and Flushing Conditions on WEDM Performance. Procedia Manufacturing 2018, 18, 130 -137.

AMA Style

T. Bergs, U. Tombul, T. Herrig, A. Klink, F. Klocke. Experimental Analysis of Influence of Discharge Current, Pulse Interval Time and Flushing Conditions on WEDM Performance. Procedia Manufacturing. 2018; 18 ():130-137.

Chicago/Turabian Style

T. Bergs; U. Tombul; T. Herrig; A. Klink; F. Klocke. 2018. "Experimental Analysis of Influence of Discharge Current, Pulse Interval Time and Flushing Conditions on WEDM Performance." Procedia Manufacturing 18, no. : 130-137.

Journal article
Published: 13 December 2018 in Procedia Manufacturing
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The connection between turbine blades and the disc is realized via profiled grooves. For manufacturing these slots into the turbine disc out of hard to machine nickel-based alloys broaching with high speed (HSS) steel is still state of the art (SotA). Compared to other manufacturing processes this technology is less productive. However, alternative manufacturing processes like broaching with cemented carbide or wire electro discharge machining (WEDM) have to be qualified concerning the rim zone and existence of residual stresses as well as productivity and flexibility due to the high demands of the aero engines sector. In this paper, surface analyses of profiled grooves manufactured by cemented carbide broaching and WEDM are made. In carbide broaching a variation of the cutting speed and the effect of its increase on the rim zone are discussed. WEDM tests are performed with four trim cuts to evaluate the effects on the rim zone. All results are compared with the state of the art process. The completion of the investigations will be an economical assessment of the different manufacturing processes.

ACS Style

T. Bergs; G. Smeets; M. Seimann; B. Doebbeler; A. Klink; F. Klocke. Surface integrity and economical assessment of alternative manufactured profiled grooves in a nickel-based alloy. Procedia Manufacturing 2018, 18, 112 -119.

AMA Style

T. Bergs, G. Smeets, M. Seimann, B. Doebbeler, A. Klink, F. Klocke. Surface integrity and economical assessment of alternative manufactured profiled grooves in a nickel-based alloy. Procedia Manufacturing. 2018; 18 ():112-119.

Chicago/Turabian Style

T. Bergs; G. Smeets; M. Seimann; B. Doebbeler; A. Klink; F. Klocke. 2018. "Surface integrity and economical assessment of alternative manufactured profiled grooves in a nickel-based alloy." Procedia Manufacturing 18, no. : 112-119.

Journal article
Published: 26 September 2018 in Procedia CIRP
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Turbochargers boost the performance of combustion engines enormously: the motors are significantly smaller at the same power, consume less fuel and their exhaust emissions are lower. A further increase in performance requires turbine wheels that can withstand even higher specific loads. Gamma titanium aluminide is the ideal material for this. However, to date there is no process chain which permits an economical manufacturing of the component. Responsible for this are the difficult-to-access, filigree flow geometries and the material properties. Thus, there is a high need for a comprehensive evaluation of alternatives for impeller manufacture. In this paper, different manufacturing chains consisting of pre-finishing and finishing of near-net-shape parts are compared to each other for a given example geometry. Electrochemical as well as Electrical Discharge Machining technologies are taken into account as alternatives for conventional milling and grinding processes for the finishing of cast blanks or samples produced by additive manufacturing. Based on a technological analysis a cost comparison is executed, which allows an economical assessment of the different process chains regarding given boundary conditions and varying production quantities.

ACS Style

A. Klink; M. Hlavac; T. Herrig; M. Holsten. Technological and Economical Assessment of Alternative Process Chains for Turbocharger Impeller Manufacture. Procedia CIRP 2018, 77, 586 -589.

AMA Style

A. Klink, M. Hlavac, T. Herrig, M. Holsten. Technological and Economical Assessment of Alternative Process Chains for Turbocharger Impeller Manufacture. Procedia CIRP. 2018; 77 ():586-589.

Chicago/Turabian Style

A. Klink; M. Hlavac; T. Herrig; M. Holsten. 2018. "Technological and Economical Assessment of Alternative Process Chains for Turbocharger Impeller Manufacture." Procedia CIRP 77, no. : 586-589.

Journal article
Published: 26 September 2018 in Procedia CIRP
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Silicon nitride (Si3N4) is a non-oxide ceramic with good thermal and mechanical properties, therefore it can be used for example as cutting edges in high performance turning processes. Because conventional machining is restricted due to hardness and brittleness, the force-free EDM is increasingly used for these ceramics. Due to the decomposition of silicon nitride during Electrical Discharge Machining (EDM) in water-based dielectric, a porous and foamy structure on the surface occurs. This has a negative impact on the workpiece behavior under mechanical load, reducing the usability in high performance processes. Therefore, improving the surface quality is crucial. So far, there are only a few published investigations focusing on wire-EDM finishing of silicon nitrides. Hence, in this paper a combination of main and trim cut technologies in CH-based dielectric for titanium nitride doped silicon nitride are examined. For these investigations, geometrical variations are used to identify the restrictions of the machinability with trim cuts. To determine the improvements, material analyses of the rim zone are applied. Based on literature, investigations regarding wire-EDM finishing of silicon nitrides are carried out.

ACS Style

F. Klocke; M. Olivier; U. Degenhardt; T. Herrig; U. Tombul; A. Klink. Investigation on Wire-EDM Finishing of Titanium Nitride Doped Silicon Nitride in CH-based Dielectrics. Procedia CIRP 2018, 77, 650 -653.

AMA Style

F. Klocke, M. Olivier, U. Degenhardt, T. Herrig, U. Tombul, A. Klink. Investigation on Wire-EDM Finishing of Titanium Nitride Doped Silicon Nitride in CH-based Dielectrics. Procedia CIRP. 2018; 77 ():650-653.

Chicago/Turabian Style

F. Klocke; M. Olivier; U. Degenhardt; T. Herrig; U. Tombul; A. Klink. 2018. "Investigation on Wire-EDM Finishing of Titanium Nitride Doped Silicon Nitride in CH-based Dielectrics." Procedia CIRP 77, no. : 650-653.

Reference work
Published: 26 February 2018 in CIRP Encyclopedia of Production Engineering
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Electro discharge machining; Spark erosion Electric discharge machining (EDM) is defined as the removal of material by electric discharges between two electrodes (workpiece and tool) in a dielectric...

ACS Style

Andreas Klink. Electric Discharge Machining. CIRP Encyclopedia of Production Engineering 2018, 1 -6.

AMA Style

Andreas Klink. Electric Discharge Machining. CIRP Encyclopedia of Production Engineering. 2018; ():1-6.

Chicago/Turabian Style

Andreas Klink. 2018. "Electric Discharge Machining." CIRP Encyclopedia of Production Engineering , no. : 1-6.

Journal article
Published: 01 January 2018 in Procedia CIRP
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ACS Style

F. Klocke; S. Harst; M. Zeis; A. Klink. Modeling and Simulation of the Microstructure Evolution of 42CrMo4 Steel During Electrochemical Machining. Procedia CIRP 2018, 68, 505 -510.

AMA Style

F. Klocke, S. Harst, M. Zeis, A. Klink. Modeling and Simulation of the Microstructure Evolution of 42CrMo4 Steel During Electrochemical Machining. Procedia CIRP. 2018; 68 ():505-510.

Chicago/Turabian Style

F. Klocke; S. Harst; M. Zeis; A. Klink. 2018. "Modeling and Simulation of the Microstructure Evolution of 42CrMo4 Steel During Electrochemical Machining." Procedia CIRP 68, no. : 505-510.

Journal article
Published: 01 January 2018 in Procedia CIRP
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In comparison to steel, titanium alloys react differently to the choice of process parameters in sinking electrical discharge machining (EDM), especially concerning the applied electrical polarity of the tool. With an anodic tool polarity, sinking EDM removal on titanium Ti6Al4 V is scarce due to titanium carbide formation, while on steel removal occurs as expected. To understand the behavior of titanium alloys, a comparative study between titanium and iron alloys in single and successive discharge experiments is performed. Ironically, single discharge removal is scarce with an anodic tool on both iron and titanium alloys. However, in ten successive discharges experiments, removal with an anodic tool increases disproportionately. Finally, the continuous EDM process with an anodic tool stops to be effective for the Ti6Al4 V machining while for steel is effective as well as efficient in terms of low tool wear. The explanation proposed is the recast layer that has a lower thermal conductivity on which successive discharges would remove material more easily. As a result, the formation of titanium carbide in Ti6Al4 V machining is likely not occurring in single discharges due to lack of continuous heat needed for carbon transfer.

ACS Style

F. Klocke; M. Mohammadnejad; M. Holsten; L. Ehle; M. Zeis; A. Klink. A Comparative Study of Polarity-related Effects in Single Discharge EDM of Titanium and Iron Alloys. Procedia CIRP 2018, 68, 52 -57.

AMA Style

F. Klocke, M. Mohammadnejad, M. Holsten, L. Ehle, M. Zeis, A. Klink. A Comparative Study of Polarity-related Effects in Single Discharge EDM of Titanium and Iron Alloys. Procedia CIRP. 2018; 68 ():52-57.

Chicago/Turabian Style

F. Klocke; M. Mohammadnejad; M. Holsten; L. Ehle; M. Zeis; A. Klink. 2018. "A Comparative Study of Polarity-related Effects in Single Discharge EDM of Titanium and Iron Alloys." Procedia CIRP 68, no. : 52-57.

Journal article
Published: 01 January 2018 in Procedia CIRP
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The advantages of ECM regarding productivity and best surface qualities are always challenged by high costs for process development and complex electrolyte flow devices. Combining the working principle of electrochemical machining (ECM) with a universal tool, like a wire, could meet these challenges. Such a wire ECM process might be able to machine flexible and efficient 2.5-dimensional geometries like fir tree slots in turbine discs. Nowadays, established manufacturing technologies for such geometries are broaching and wire electrical discharge machining (wire EDM). Nevertheless, high requirements on surface integrity of turbine parts need an intensive process development and – in case of wire EDM – trim cuts to reduce the heat affected rim zone. In the past, few studies dealt with the development of a wire ECM process to meet these challenges. However, previous concepts of wire ECM were only suitable for micro machining applications. Due to insufficient flushing concepts, the application of the process for machining macro geometries with higher cutting rates failed. Therefore, this paper presents experimental investigations on wire electrochemical machining of macro geometries. An axial flushing approach with a rotating tool electrode is used in order to optimize electrolyte flushing and thus, to increase cutting rates. The influences of different machining parameters on cutting kerf, surface integrity and cutting rate will be presented.

ACS Style

F. Klocke; T. Herrig; M. Zeis; A. Klink. Experimental Investigations of Cutting Rates and Surface Integrity in Wire Electrochemical Machining with Rotating Electrode. Procedia CIRP 2018, 68, 725 -730.

AMA Style

F. Klocke, T. Herrig, M. Zeis, A. Klink. Experimental Investigations of Cutting Rates and Surface Integrity in Wire Electrochemical Machining with Rotating Electrode. Procedia CIRP. 2018; 68 ():725-730.

Chicago/Turabian Style

F. Klocke; T. Herrig; M. Zeis; A. Klink. 2018. "Experimental Investigations of Cutting Rates and Surface Integrity in Wire Electrochemical Machining with Rotating Electrode." Procedia CIRP 68, no. : 725-730.

Journal article
Published: 01 January 2018 in Procedia CIRP
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Because of their lightweight, high-temperature corrosion resistance and fatigue property, titanium alloys are ideal for use in turbomachinery, medical and chemical areas with corrosive environments and precision mechanics as used in aeronautical applications. Wire electro discharge machining (WEDM) is a nearly force free process and hence beneficial compared to classical production technologies when it comes to the production of filigree parts with high aspect ratios. Beside the well-known fact of the heat affected rim zone at WEDM machined parts, titanium alloys have another material specific drawback, called ‘alpha case’, which is developed by diffusion driven interstitials, such as carbon, nitrogen and especially oxygen. The alpha-case is a hard to remove superficial defect, which leads to crack initiation and propagation. The influence of water- and CH-based dielectrics as a source of diffusitives on the formation of alpha-case have to be investigated to predict the part’s fatigue strength.

ACS Style

F. Klocke; G. Smeets; M. Kittel; M. Olivier; R. Hama-Saleh; S. Harst; A. Klink. Comparison of material specific rim zone effects of Ti6Al4V machined by wire EDM in water- and CH- based dielectrics. Procedia CIRP 2018, 71, 238 -243.

AMA Style

F. Klocke, G. Smeets, M. Kittel, M. Olivier, R. Hama-Saleh, S. Harst, A. Klink. Comparison of material specific rim zone effects of Ti6Al4V machined by wire EDM in water- and CH- based dielectrics. Procedia CIRP. 2018; 71 ():238-243.

Chicago/Turabian Style

F. Klocke; G. Smeets; M. Kittel; M. Olivier; R. Hama-Saleh; S. Harst; A. Klink. 2018. "Comparison of material specific rim zone effects of Ti6Al4V machined by wire EDM in water- and CH- based dielectrics." Procedia CIRP 71, no. : 238-243.