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  • 51.
    Repo, Jari
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Wretland, Anders
    GKN Aerospace Engine Systems AB, Dept. 9634 – TL-3, SE-46181 Trollhättan, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Tu, Juei-feng
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). North Carolina State University, Dept. of Mechanical and Aerospace Engineering, Raleigh, USA.
    In-Process Tool Wear Detection Using Internal Encoder Signals for Unmanned Robust Machining2016Ingår i: High Speed Machining, Vol. 2, nr 1, s. 37-50Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Automated Tool Condition Monitoring (TCM) often relies on additional sensors sensitive to tool wear to achieve robust machining processes. The need of additional sensors could impede the implementation of tool monitoring systems in industry due to the cost and retrofitting difficulties. This paper has investigated the use of existing position encoder signals to monitor a special face turning process with constant feed per revolution and machining speed. A signal processing method by converting encoder signals into a complex-valued form and a new vibration signature extraction method based on phase function were developed to analyze the encoder signals in the frequency domain. The cumulative spectrum indicated that the spectral energy would shift from the lower to the higher frequency band with increasing cutting load. The embedded vibration signatures extracted from the encoder signals provided real-time detectability of the machining condition with distinguishable spectral modes. The embedded vibration signatures extracted from the encoder signals provided additional detectability of the machining condition with distinguishable spectral modes. In particular, tool chipping manifested itself as significant amplitude changes at a specific frequency band 20-30 Hz in the extracted vibration signatures. A new monitoring metric based on the XY-plane modulations combined with statistical process control charts was proposed and shown to be a robust tool wear and tool wear rate indicator. The results show that when tool chipping occurred, it could be detected in real-time when this this tool wear rate value jumped in combination with breach of the control limits. This confirms that internal encoder signals, together with the proposed metric, could be a robust in-process tool wear monitor.

    Ladda ner fulltext (pdf)
    [HSM 2016] In-Process Tool Wear Detection Using Internal Encoder Signals for U R M
  • 52.
    Tamil Alagan, Nageswaran
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Hoier, Philipp
    Chalmers University of Technology, Department of Industrial and Materials Science, SE-412 96 Gothenburg, Sweden.
    Klement, Uta
    Chalmers University of Technology, Department of Industrial and Materials Science, SE-412 96 Gothenburg, Sweden.
    Wretland, Anders
    GKN Aerospace Engine Systems AB, SE-461 81 Trollhättan, Sweden.
    Influence of Surface Features for Increased Heat Dissipation on Tool Wear2018Ingår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 11, nr 5, artikel-id E664Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The critical problems faced during the machining process of heat resistant superalloys, (HRSA), is the concentration of heat in the cutting zone and the difficulty in dissipating it. The concentrated heat in the cutting zone has a negative influence on the tool life and surface quality of the machined surface, which in turn, contributes to higher manufacturing costs. This paper investigates improved heat dissipation from the cutting zone on the tool wear through surface features on the cutting tools. Firstly, the objective was to increase the available surface area in high temperature regions of the cutting tool. Secondly, multiple surface features were fabricated for the purpose of acting as channels in the rake face to create better access for the coolant to the proximity of the cutting edge. The purpose was thereby to improve the cooling of the cutting edge itself, which exhibits the highest temperature during machining. These modified inserts were experimentally investigated in face turning of Alloy 718 with high-pressure coolant. Overall results exhibited that surface featured inserts decreased flank wear, abrasion of the flank face, cutting edge deterioration and crater wear probably due to better heat dissipation from the cutting zone.

  • 53.
    Tamil Alagan, Nageswaran
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Wretland, Anders
    GKN Aerospace Engine Systems AB, Trollhättan, 461 81, Sweden.
    Investigation of Modified Cutting Insert with Forced Coolant Application in Machining of Alloy 7182016Ingår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 42, s. 481-486Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abstract In the last decades machining methods have witnessed an advancement in both cutting tools and coolant/lubrication, sometimes in combination with high pressure jet. The aim of this work is to investigate a modified cutting insert with forced coolant application, FCA, how it influences the tool-chip contact in the secondary shear zone and how it affects the tool wear when turning Alloy 718. During the machining process the main and frequent problems are heat generation and friction in the cutting zone, which has a direct impact on the cutting tool life. High pressure jet cooling have headwayed the cutting technology for the last five decades, showing an improvment of tool life, reduced temperature in the cutting zone and better surface integrity of the workpiece. These developments have practically enhanced the capability and quality in machining of superalloys. This paper is an advancement of the previous work, increasing surface area of the insert, with a additional channel design to improve the coolant reachability in the tool-chip contact area on the rake face. The influence in tool wear has been investigated. Through a set of experiments, a channel design insert with forced coolant application, has shown about 24-33% decrease in tool wear compared to only a textured insert. Hybrid inserts with its cooling and channel features have even widened the operational cutting region with significantly less tool wear.

  • 54.
    Tamil Alagan, Nageswaran
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Wretland, Anders
    GKN Aerospace Engine Systems AB, Trollhättan, Sweden.
    Next Generation Insert for Forced Coolant Application in Machining of Inconel 7182016Ingår i: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 836-837, s. 340-347Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Machining technology has undergone an extensive evolution throughout the last decades in its capability to machine hard-to-cut material. This paper will discuss about the next generation insert with cooling feature coupled with forced coolant in machining Inconel 718. The geometry of the insert was changed in a way which has enlarged the surface area approximately 12% compared to regular insert named as nusselt insert. The idea applied in “nusselt insert” was the relation of increase in surface area to heat dissipation. Forced coolant application has become a way to improve existing metal cutting concepts and improve their current material removal rates without any need for a reengineered machining process. Experiments conducted on the inserts is that the first experiment of its kind in machining technology together with forced coolant and tested in four different inserts. The primary focus of the work was the investigation of the relation between the heat dissipation with an increase in surface area/mass ratio in the cutting interface based on its influence on tool wear. The experimental results showed the nusselt insert have better ability for heat dissipation which has led to significant reduce in tool wear and successfully facing Inconel 718 at vc 105 m/min, f 0.3 mm/rev and ap 1 mm where the regular insert had a catastrophic failure at vc 90 m/min, f 0.1 mm/rev and ap 1 mm. Nusselt insert has shown to increase MRR significantly compared to regular insert.

  • 55.
    Tamil Alagan, Nageswaran
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Hoier, Philipp
    Chalmers University of Technology, Department of Industrial and Materials Science, Gothenburg, Sweden.
    Zeman, Pavel
    Department of Production Machines and Equipment, Faculty of Mechanica lEngineering, Center of Advanced AerospaceTechnology, CzechTechnical University in Prague, Czech Republic.
    Klement, Uta
    Chalmers University of Technology, Department of Industrial and Materials Science, Gothenburg, Swede.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Wretland, Anders
    GKN Aerospace Engine Systems AB,Trollhättan, Sweden.
    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 7182019Ingår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 434-435, artikel-id 102922Artikel i tidskrift (Refereegranskat)
    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.

  • 56.
    Tamil Alagan, Nageswaran
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Höier, Philipp
    Chalmers University of Technology, Department of Industrial and Materials Science, Göteborg, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Klement, Uta
    Chalmers University of Technology, Department of Industrial and Materials Science, Göteborg, Sweden.
    Wretland, Anders
    GKN Aerospace Engine Systems AB, Trollhättan, Sweden.
    Coolant boiling and cavitation wear: a new tool wear mechanism on WC tools in machining Alloy 718 with high-pressure coolant2020Ingår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 452-453, artikel-id 203284Artikel i tidskrift (Refereegranskat)
    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

  • 57.
    Tamil Alagan, Nageswaran
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Zeman, Pavel
    Czech Technical University in Prague, Research Center of Manufacturing Technology, Prague, Czech Republic.
    Hoier, Philipp
    Chalmers University of Technology, Department of Industrial and Materials Science, Gothenburg, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Klement, Uta
    Chalmers University of Technology, Department of Industrial and Materials Science, Gothenburg, Sweden.
    Investigation of micro-textured cutting tools used for face turning of alloy 718 with high-pressure cooling2019Ingår i: Journal of manufacturing processes, ISSN 1526-6125, Vol. 37, s. 606-616Artikel i tidskrift (Refereegranskat)
    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.

  • 58.
    Wanner, Bertil
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för maskinteknik.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för maskinteknik. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för maskinteknik. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pejryd, Lars
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Cutter Exit Effects during Milling of Thin-walled Inconel 7182012Ingår i: Advanced Materials Research, ISSN 1022-6680, E-ISSN 1662-8985, Vol. 590, s. 297-308Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During milling of thin-walled components, chatter vibrations give rise to process issues. These include dimensional inaccuracy, damaged and scrap parts, and damaged cutting tools. This, in turn, leads to loss of production time with increasing cost as a consequence. This paper identifies the force profile during a single cut milling process. It focuses on the exit and post-exit behavior of the cut and discusses the process dynamics. The force profiles of various tool-to-workpiece positions are analyzed as regards the exit and post exit phases. A standard on-the-market cutter and a specially designed zero rake cutter are used in the investigation. Finally, a time-domain simulation of the force is performed and compared to the experimental results. The study concludes that a small change in exit angle may result in a considerable improvement in cutting behavior. In addition, the tool position should be chosen so that the cutter exits in the least flexible direction possible for the workpiece.

  • 59.
    Wanner, Bertil
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pejryd, Lars
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Milling Strategies for Thin-walled Components2012Ingår i: Advanced Materials Research, ISSN 1022-6680, E-ISSN 1662-8985, Vol. 498, s. 177-182Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent developments in the Aerospace industry have led to thin-walled, reduced-weight engine designs. Due to demands in manufacturing, production speeds and material removal rates (MRR) have increased. As component wall thickness gets thinner, the consequence oftentimes is an increase in chatter vibrations. This paper suggests that a correctly chosen tool-to-workpiece offset geometry may lead to a robust and chatter-free process. The results show the differences in force response for three geometries while varying the overhang of the workpiece. This is part of a concerted effort to develop a robust methodology for the prediction of chatter vibrations during milling operations of thin-walled Aerospace components. This paper outlines certain robust machining practices. It also analyzes the criticality of the choice of offset between tool and workpiece during milling setup as well as the effects that the entry and exit of cut have on system vibrations.

  • 60.
    Wanner, Bertil
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pejryd, Lars
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Process Stability Strategies in Milling of Thin-walled Inconel 7182012Ingår i: The 4th Manufacturing engineering society international conference (MESIC 2011): 21–23 September 2011, Cadiz, Spain / [ed] M. Marcos, J. Salguero, American Institute of Physics (AIP), 2012, Vol. 1431, s. 465-472Konferensbidrag (Refereegranskat)
    Abstract [en]

    Trends in Aerospace development have led to thin-walled, reduced-weight engine designs. The demands in manufacturing have forced production speeds and material removal rates (MRR) to increase. As component wall thickness gets thinner, the consequence oftentimes is an increase in chatter vibrations. This paper suggests that a correctly chosen tool-to-workpiece offset geometry may lead to a robust and chatter free process. The results show the differences in force response for three geometries while varying the height overhang of the workpiece. This is part of a concerted effort to develop a robust methodology for the prediction of chatter vibrations during milling operations of thin-walled Aerospace components. This paper gives guidelines on how to accomplish robust machining practices. It also answers the following questions: How critical is the choice of offset between tool and workpiece during milling setup? And what effects do the entry and exit of cut have on system vibrations?

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