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Holmberg, J., Wretland, A., Berglund, J. & Beno, T. (2020). A detailed investigation of residual stresses after milling Inconel 718 using typical production parameters for assessment of affected depth. Materials Today Communications, 24, Article ID 100958.
Open this publication in new window or tab >>A detailed investigation of residual stresses after milling Inconel 718 using typical production parameters for assessment of affected depth
2020 (English)In: Materials Today Communications, ISSN 2352-4928, Vol. 24, article id 100958Article in journal (Refereed) Published
Abstract [en]

Production of superalloy gas turbine parts involves time consuming milling operations typically performed in a sequence from rough to finish milling. Rough milling using ceramic inserts allows high removal rates but causes severe sub-surface impact. A relatively large allowance is therefore left for subsequent cemented carbide milling. With increased knowledge of the affected depth it will be possible to reduce the machining allowance and increase efficiency of the manufacturing process. Milling Inconel 718 using typical production parameters has been investigated using new and worn ceramic and cemented carbide inserts. Residual stresses in a milled slot were measured by x-ray diffraction. Stresses were measured laterally across the slot and below the surface, to study the depth affected by milling. The most important result from this work is the development of a framework concerning how to evaluate the affected depth for a milling operation. The evaluation of a single milled slot shows great potential for determining the optimum allowance for machining. Our results show that the residual stresses are greatly affected by the ceramic and cemented carbide milling; both regarding depth as well as distribution across the milled slot. It has been shown that it is important to consider that the stresses across a milled slot are the highest in the center of the slot and gradually decrease toward the edges. Different inserts, ceramic and cemented carbide, and tool wear, alter how the stresses are distributed across the slot and the affected depth. © 2020 The Authors

Keywords
Carbide cutting tools; Carbide tools; Carbides; Milling (machining); Residual stresses, Allowance determination; Alloy 718; High speed milling; Material removal rate; Surface integrity, Cutting tools
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology; ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-14992 (URN)10.1016/j.mtcomm.2020.100958 (DOI)2-s2.0-85079036532 (Scopus ID)
Available from: 2020-02-24 Created: 2020-02-24 Last updated: 2020-02-24Bibliographically approved
Tamil Alagan, N., Höier, P., Beno, T., Klement, U. & Wretland, A. (2020). Coolant boiling and cavitation wear: a new tool wear mechanism on WC tools in machining Alloy 718 with high-pressure coolant. Wear, 452-453, Article ID 203284.
Open this publication in new window or tab >>Coolant boiling and cavitation wear: a new tool wear mechanism on WC tools in machining Alloy 718 with high-pressure coolant
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2020 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 452-453, article id 203284Article in journal (Refereed) Published
Abstract [en]

In recent years, research interest in liquid coolant media applied to the tool–workpiece interface (the tertiary shear zone) has grown considerably. In particular, attention has increased for work where the media has been applied under high-pressure. This is most likely triggered by the positive results reported on similar applications, but with coolant media directed towards the rake face of the cutting tool (the secondary shear zone). The most typical applications have not surprisingly been related to the machining of Heat Resistant Super Alloys (HRSA) or other “difficult to machine” alloys where the main intention has been to extend tool life and improve surface finish through reduced shear zone temperatures. Concurrently, these achievements have revealed a knowledge gap and unlocked a new research area in understanding the effects and influences of coolant media applied on super-heated surfaces under high-pressure conditions. The aim of this study is to investigate the “coolant boiling and cavitation” phenomena that emerges during the application of coolant under high-pressure to the flank face of an uncoated WC tool while turning Alloy 718. The experimental campaign was conducted in three aspects: varying flank (coolant media) pressure; varying spiral cutting length (SCL); and varying cutting speed. The results revealed that the location and size of the coolant-boiling region correlated with flank wear, coolant pressure and vapour pressure of the coolant at the investigated pressure levels. Further, the results showed that coolant applied with a lower pressure than the vapour pressure of the coolant itself caused the “Leidenfrost” effect. This then acts as a coolant media barrier and effectively reduces the heat transport from the cutting zone. Further, erosion pits were observed on small areas of the cutting tool, resembling the typical signs of cavitation (usually found in much different applications such as pumps and propellers). The discovered wear mechanism denoted as “Cavitation Wear” was used as base for the discussion aimed to deepen the understanding of the conditions close to the sliding interface between the tool and the workpiece. Even though “Cavitation Wear” has been widely reported in hydraulic systems like pumps and water turbines, it is a new phenomenon to be seen on cutting tools while using high-pressure flank cooling. © 2020 The Authors

National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:hv:diva-15156 (URN)10.1016/j.wear.2020.203284 (DOI)2-s2.0-85083650341 (Scopus ID)
Funder
Knowledge Foundation, 20140130Region Västra Götaland
Available from: 2020-05-04 Created: 2020-05-04 Last updated: 2020-05-04
Devotta, A. M., Sivaprasad, P. V., Beno, T., Eynian, M., Hurtig, K., Magnevall, M. & Lundblad, M. (2019). A modified Johnson-Cook model for ferritic-pearlitic steel in dynamic strain aging regime. Metals, 9(5), Article ID 528.
Open this publication in new window or tab >>A modified Johnson-Cook model for ferritic-pearlitic steel in dynamic strain aging regime
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2019 (English)In: Metals, ISSN 2075-4701, Vol. 9, no 5, article id 528Article in journal (Refereed) Published
Abstract [en]

In this study, the flow stress behavior of ferritic-pearlitic steel (C45E steel) is investigated through isothermal compression testing at different strain rates (1 s-1, 5 s-1, and 60 s-1) and temperatures ranging from 200 to 700 °C. The stress-strain curves obtained from experimental testing were post-processed to obtain true stress-true plastic strain curves. To fit the experimental data to well-known material models, Johnson-Cook (J-C) model was investigated and found to have a poor fit. Analysis of the flow stress as a function of temperature and strain rate showed that among other deformation mechanisms dynamic strain aging mechanism was active between the temperature range 200 and 400 °C for varying strain rates and J-C model is unable to capture this phenomenon. This lead to the need to modify the J-C model for the material under investigation. Therefore, the original J-C model parameters A, B and n are modified using the polynomial equation to capture its dependence on temperature and strain rate. The results show the ability of the modified J-C model to describe the flow behavior satisfactorily while dynamic strain aging was operative. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.

Place, publisher, year, edition, pages
MDPI AG, 2019
Keywords
flow stress; modified Johnson-Cook model; dynamic strain aging
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-13989 (URN)10.3390/met9050528 (DOI)000478818700046 ()2-s2.0-85066741813 (Scopus ID)
Funder
Swedish Research Council, 20110263, 20140130
Available from: 2019-06-20 Created: 2019-06-20 Last updated: 2020-05-04Bibliographically approved
Agic, A., Eynian, M., Ståhl, J. E. & Beno, T. (2019). Dynamic effects on cutting forces with highly positive versus highly negative cutting edge geometries. International Journal on Interactive Design and Manufacturing, 13(2), 557-565
Open this publication in new window or tab >>Dynamic effects on cutting forces with highly positive versus highly negative cutting edge geometries
2019 (English)In: International Journal on Interactive Design and Manufacturing, ISSN 1955-2513, E-ISSN 1955-2505, Vol. 13, no 2, p. 557-565Article in journal (Refereed) Published
Abstract [en]

Understanding the influence of the cutting edge geometry on the development of cutting forces during the milling process is of high importance in order to predict the mechanical loads on the cutting edge as well as the dynamic behavior on the milling tool. The work conducted in this study involves the force development over the entire engagement of a flute in milling, from peak force during the entry phase until the exit phase. The results show a significant difference in the behavior of the cutting process for a highly positive versus a highly negative cutting edge geometry. The negative edge geometry gives rise to larger force magnitudes and very similar developments of the tangential and radial cutting force. The positive cutting edge geometry produces considerably different developments of the tangential and radial cutting force. In case of positive cutting edge geometry, the radial cutting force increases while the uncut chip thickness decreases directly after the entry phase; reaching the peak value after a certain delay. The radial force fluctuation is significantly higher for the positive cutting edge geometry. The understanding of such behavior is important for modelling of the milling process, the design of the cutting edge and the interactive design of digital applications for the selection of the cutting parameters.

Keywords
Milling, Cutting force, Cutting edge geometry, Frequency spectrum, RMS
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-13302 (URN)10.1007/s12008-018-0513-5 (DOI)000468115700013 ()2-s2.0-85058211299 (Scopus ID)
Funder
Knowledge Foundation
Note

Funders: Seco Tools

Available from: 2019-01-08 Created: 2019-01-08 Last updated: 2020-02-03Bibliographically approved
Tamil Alagan, N., Hoier, P., Zeman, P., Klement, U., Beno, T. & Wretland, A. (2019). Effects of high pressure cooling in the flank and rake faces of WC tool on the tool wear mechanism and process conditions in turning of alloy 718. Wear, 434-435, Article ID 102922.
Open this publication in new window or tab >>Effects of high pressure cooling in the flank and rake faces of WC tool on the tool wear mechanism and process conditions in turning of alloy 718
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2019 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 434-435, article id 102922Article in journal (Refereed) Published
Abstract [en]

The exceptional properties of Heat Resistant Super Alloys (HRSA) justify the search for advanced technologiesthat can improve the capability of machining these materials. One such advanced technology is the applicationof a coolant at high pressure while machining, a strategic solution known for at least six decades. The aim is toachieve extended tool life, better chip control and improved surface finish. Another aim is to control the temperature in the workpiece/tool interface targeting for optimum cutting conditions. In most of the existing applications with high-pressure coolant media, the nozzles are positioned on the rake face side of the insert andthey are directed towards the cutting edge (the high-temperature area). The coolant is applied at high-pressureto improve the penetration of the cooling media along the cutting edge in the interface between the insert andworkpiece material (chip) as well as to increase chip breakability. However, the corresponding infusion ofcoolant media in the interface between the flank face of the insert and the work material (tertiary shear zone) hasbeen previously only scarcely addressed, as is the combined effect of coolant applications on rake and clearancesides of the insert. The present work addresses the influence of different pressure conditions in (flank: 0, 4 and8 MPa; rake: 8 and 16 MPa) on maximum flank wear, flank wear area, tool wear mechanism, and overall processperformance. Round uncoated inserts are used in a set of face turning experiments, conducted on the widely usedHRSA "Alloy 718" and run in two condition tests with respect to cutting speed (45 (low) and 90 (high) m/min).The results show that an increase in rake pressure from 8 to 16 MPa has certainly a positive impact on tool life.Furthermore, at higher vc of 90 m/min, cutting edge deterioration: due to an extensive abrasion and crack in thewear zone were the dominant wear mechanism. Nevertheless, the increase in coolant pressure condition to16 MPa reduced the amount of abrasion on the tool compared to 8 MPa. At the lower cutting speed, no crack orplastic deformation or extensive abrasion were found. When using 8 MPa pressure of coolant media on the flank,the wear was reduced by 20% compared to flood cooling conditions. Application of high-pressure cooling on theflank face has a positive effect on tool life and overall machining performance of Alloy 718.

Keywords
Alloy 718, Cemented tungsten carbide, High-pressure coolant, Tool wear mechanism, Crack, Coolant-boiling
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology; ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-14330 (URN)10.1016/j.wear.2019.05.037 (DOI)000487194500001 ()2-s2.0-85070612386 (Scopus ID)
Funder
Knowledge Foundation, 20140130Region Västra Götaland
Note

Funders:ESIF , EU Operational Programme Research , Development and Education; the Centre of Advanced Aerospace Technology ( CZ.02.1.01/0.0/0.0/16_019/0000826 )

Available from: 2019-08-26 Created: 2019-08-26 Last updated: 2020-01-30Bibliographically approved
Holmberg, J., Wretland, A., Berglund, J. & Beno, T. (2019). Evaluation of surface integrity after high energy machining with EDM, Laser Beam Machining and Abrasive Water Jet Machining of Alloy 718. The International Journal of Advanced Manufacturing Technology, 100(5-8), 1575-1591
Open this publication in new window or tab >>Evaluation of surface integrity after high energy machining with EDM, Laser Beam Machining and Abrasive Water Jet Machining of Alloy 718
2019 (English)In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 100, no 5-8, p. 1575-1591Article in journal (Refereed) Published
Abstract [en]

Development of future aero engine components based on new design strategies utilising topological optimisation and additive manufacturing has in the past years become a reality. This allows for designs that involve geometries of "free form" surfaces and material combinations that could be difficult to machine using conventional milling. Hence, alternative manufacturing routes using non-conventional high energy methods are interesting to explore. In this investigation, the three high energy machining methods abrasive water jet machining (AWJM), electrical discharge machining (EDM) and laser beam machining (LBM) have been compared in terms of surface integrity to the reference, a ball nosed end milled surface. The results showed great influence on the surface integrity from the different machining methods. It was concluded that AWJM resulted in the highest quality regarding surface integrity properties with compressive residual stresses in the surface region and a low surface roughness with texture from the abrasive erosion. Further, it was shown that EDM resulted in shallow tensile residual stresses in the surface and an isotropic surface texture with higher surface roughness. However, even though both methods could be considered as possible alternatives to conventional milling they require post processing. The reason is that the surfaces need to be cleaned from either abrasive medium from AWJM or recast layer from EDM. It was further concluded that LBM should not be considered as an alternative in this case due to the deep detrimental impact from the machining process.Keywords

Keywords
Non-conventional machining, EDM, Laser beam machining, Abrasive water jet machining, Surface integrity, Residual stress, EBSD, Topography
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology; ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-12189 (URN)10.1007/s00170-018-2697-z (DOI)2-s2.0-85054583255 (Scopus ID)
Funder
Vinnova, 2013-04666; 2015-06047
Note

First Online: 05 October 2018

Available from: 2018-03-02 Created: 2018-03-02 Last updated: 2020-01-15Bibliographically approved
Agic, A., Eynian, M., Ståhl, J.-E. -. & Beno, T. (2019). Experimental analysis of cutting edge effects on vibrations in end milling. CIRP - Journal of Manufacturing Science and Technology, 24, 66-74
Open this publication in new window or tab >>Experimental analysis of cutting edge effects on vibrations in end milling
2019 (English)In: CIRP - Journal of Manufacturing Science and Technology, ISSN 1755-5817, E-ISSN 1878-0016, Vol. 24, p. 66-74Article in journal (Refereed) Published
Abstract [en]

The ability to minimize vibrations in milling by the selection of cutting edge geometry and appropriate cutting conditions is an important asset in the optimization of the cutting process. This paper presents a measurement method and a signal processing technique to characterize and quantify the magnitude of the vibrations in an end milling application. Developed methods are then used to investigate the effects of various cutting edge geometries on vibrations in end milling. The experiments are carried out with five cutting edge geometries that are frequently used in machining industry for a wide range of milling applications. The results show that a modest protection chamfer combined with a relatively high rake angle has, for the most of cutting conditions, a reducing effect on vibration magnitudes. Furthermore, dynamics of a highly positive versus a highly negative cutting geometry is explored in time domain and its dependency on cutting conditions is presented. The results give concrete indications about the most optimal cutting edge geometry and cutting conditions in terms of dynamic behavior of the tool.

Keywords
Milling, Acceleration, Cutting edge, Frequency spectrum, Rake angle, Chamfer
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-13735 (URN)10.1016/j.cirpj.2018.11.001 (DOI)000460558000007 ()2-s2.0-85057229226 (Scopus ID)
Funder
Knowledge Foundation
Note

Funders: Seco Tools

Available from: 2019-03-21 Created: 2019-03-21 Last updated: 2020-02-04Bibliographically approved
Tamil Alagan, N., Zeman, P., Hoier, P., Beno, T. & Klement, U. (2019). Investigation of micro-textured cutting tools used for face turning of alloy 718 with high-pressure cooling. Journal of manufacturing processes, 37, 606-616
Open this publication in new window or tab >>Investigation of micro-textured cutting tools used for face turning of alloy 718 with high-pressure cooling
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2019 (English)In: Journal of manufacturing processes, ISSN 1526-6125, Vol. 37, p. 606-616Article in journal (Refereed) Published
Abstract [en]

There is an increasing demand to improve the service life of cutting tools during machining of heat resistant superalloys (HRSA). Various studies showed that textured cutting tools improved the tribological properties and reduced cutting forces, temperature, and tool wear. Surface texturing can be seen as a futuristic design to improve the performance of the cutting tool and to increase productivity. However, only limited research has been conducted in machining superalloys with textured inserts and high-pressure coolant. In this work, three different micro texture designs on both rake and flank face are investigated in combination with high-pressure coolant in machining Alloy 718. Due to better tool life predictability, carbide cutting tools are used in machining components made from superalloys. However, the disadvantage is that machining can only be done at lower cutting speed/feed rate/depth of cut with high tool wear rates. The experimental investigation using different tool wear analysis methods showed that the combination of a cylindrical dimple on the rake and the square pyramid texture on the flank surface improved the wear resistance of the tool. An increase in tool life of about 30% was achieved as compared with a regular insert for the investigated cutting conditions. Different levels of adhering workpiece material were observed on the rake face of textured tools. Furthermore, the chip backside showed imprints from the tool textures. The tool textures on the rake face have influenced the tool-chip friction conditions during cutting.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Alloy 718Face turningHigh-pressure coolantNext generation cutting toolsTextured insertsTool wear
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology; ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-13430 (URN)10.1016/j.jmapro.2018.12.023 (DOI)000465052000058 ()2-s2.0-85060085875 (Scopus ID)
Funder
Region Västra GötalandKnowledge Foundation, 20140130
Available from: 2019-01-21 Created: 2019-01-21 Last updated: 2020-02-04Bibliographically approved
Bonilla Hernández, A. E., Lu, T., Beno, T., Fredriksson, C. & Jawahir, I. S. (2019). Process sustainability evaluation for manufacturing of a component with the 6R application. Paper presented at Conference of 16th Global Conference on Sustainable Manufacturing, GCSM 2018 ; Conference Date: 2 October 2018 Through 4 October 2018. Procedia Manufacturing, 33, 546-553
Open this publication in new window or tab >>Process sustainability evaluation for manufacturing of a component with the 6R application
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2019 (English)In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 33, p. 546-553Article in journal (Refereed) Published
Abstract [en]

Sustainability in manufacturing can be evaluated at product, process and system levels. The 6R methodology for sustainability enhancement in manufacturing processes includes: reduced use of materials, energy, water and other resources; reusing of products/components; recovery and recycling of materials/components; remanufacturing of products; and redesigning of products to utilize recovered materials/resources. Although manufacturing processes can be evaluated by their productivity, quality and cost, process sustainability assessment makes it a complete evaluation. This paper presents a 6R-based evaluation method for sustainable manufacturing in terms of specific metrics within six major metrics clusters: environmental impact, energy consumption, waste management, cost, resource utilization and society/personnel health/operational safety. Manufacturing processes such as casting, welding, turning, milling, drilling, grinding, etc., can be evaluated using this methodology. A case study for machining processes is presented as an example based on the proposed metrics. © 2019 The Authors. Published by Elsevier B.V.

National Category
Production Engineering, Human Work Science and Ergonomics
Research subject
Production Technology; ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-14467 (URN)10.1016/j.promfg.2019.04.068 (DOI)2-s2.0-85068575451 (Scopus ID)
Conference
Conference of 16th Global Conference on Sustainable Manufacturing, GCSM 2018 ; Conference Date: 2 October 2018 Through 4 October 2018
Funder
Knowledge Foundation
Available from: 2019-10-01 Created: 2019-10-01 Last updated: 2020-01-27Bibliographically approved
Devotta, A. M., Beno, T. & Eynian, M. (2019). Simulation-Based Product Development Framework for Cutting Tool Geometry Design. In: Dimitrov, D., Hagedorn-Hansen, D. & Von Leipzig, K. (Ed.), Conference Proceedings: International Conference on Competitive Manufacturing, COMA19, presented at Stellenbosch Univerisy, January 30 - February 1 2019, Stellenbosch University, Stellenbosch, South Africa.. Paper presented at International Conference on Competitive Manufacturing, COMA19, presented at Stellenbosch Univerisy, January 30 - February 1 2019, Stellenbosch University, Stellenbosch, South Africa. (pp. 47-52). Stellenbosch University
Open this publication in new window or tab >>Simulation-Based Product Development Framework for Cutting Tool Geometry Design
2019 (English)In: Conference Proceedings: International Conference on Competitive Manufacturing, COMA19, presented at Stellenbosch Univerisy, January 30 - February 1 2019, Stellenbosch University, Stellenbosch, South Africa. / [ed] Dimitrov, D., Hagedorn-Hansen, D. & Von Leipzig, K., Stellenbosch University , 2019, p. 47-52Conference paper, Published paper (Refereed)
Abstract [en]

Cutting tool geometry design has traditionally relied on experimental studies; while engineering simulations, to the level of industrial deployment, have been developed only in the last couple of decades. With the development of simulation capability across length scales from micro to macro,cutting tool geometry development includes engineering data development for its efficient utilization. This calls for the design of a simulation-based approach in the design of cutting tool geometry so that the engineering data can be generated for different machining applications (e.g.digital twin). In this study, the needs for engineering model development of different stages of cutting tool design evaluation is assessed. To this end, some of the previously developed engineering models have been evaluated for evaluation of chip form morphology in industrially relevant nose turning process, work piece material behavior modeling and damage modeling for the prediction of chip shape morphology. The study shows the possibility for the developed models to act as building blocks of a digital twin. It also shows the need for engineering model development for different aspects of cutting tool design, its advantages, limitations, and prospects.

Place, publisher, year, edition, pages
Stellenbosch University, 2019
Keywords
Product design, Simulation, Finite element method
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology; ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-14863 (URN)978-0-7972-1779-9 (ISBN)
Conference
International Conference on Competitive Manufacturing, COMA19, presented at Stellenbosch Univerisy, January 30 - February 1 2019, Stellenbosch University, Stellenbosch, South Africa.
Available from: 2020-01-15 Created: 2020-01-15 Last updated: 2020-01-15Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0976-9820

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