Pub Date : 2021-09-03DOI: 10.1080/10910344.2021.1971704
Tuğçe Tezel
Abstract Fused deposition modeling (FDM) is an additive manufacturing (AM) technique that has emerged as a suitable application in different areas, including machine design and manufacturing. The main advantages of this method over conventional methods include that it is faster and produces less material waste. Besides, AM offers computer-aided design and manufacturing but does not include any limitations on the product's geometry and does not require any extra tools. End milling is a conventional manufacturing process used for profiling, slotting, and facing. In this study, at the point of overcoming the weaknesses of AM surface quality, it was investigated whether the cast polymer's surface quality could be reached with hybrid manufacturing (AM + milling). For this reason, the parts produced by FDM were subjected to end milling, and the effect of cutting depth, feed rate, and rotation speed on surface quality and chip type were investigated. The results obtained are compared with the results of the milling operation of cast polyamide. For all results, surface quality increases with a rising feed rate. In general, the surface quality obtained by milling parts produced using FDM is low, but each manufacturing technique is affected differently by the end milling conditions. Low rotation speed and high feed rates should be preferred to obtain the desired surface quality from FDM printed polyamide parts.
{"title":"The effect of machining parameters on the surface quality of 3D printed and cast polyamide","authors":"Tuğçe Tezel","doi":"10.1080/10910344.2021.1971704","DOIUrl":"https://doi.org/10.1080/10910344.2021.1971704","url":null,"abstract":"Abstract Fused deposition modeling (FDM) is an additive manufacturing (AM) technique that has emerged as a suitable application in different areas, including machine design and manufacturing. The main advantages of this method over conventional methods include that it is faster and produces less material waste. Besides, AM offers computer-aided design and manufacturing but does not include any limitations on the product's geometry and does not require any extra tools. End milling is a conventional manufacturing process used for profiling, slotting, and facing. In this study, at the point of overcoming the weaknesses of AM surface quality, it was investigated whether the cast polymer's surface quality could be reached with hybrid manufacturing (AM + milling). For this reason, the parts produced by FDM were subjected to end milling, and the effect of cutting depth, feed rate, and rotation speed on surface quality and chip type were investigated. The results obtained are compared with the results of the milling operation of cast polyamide. For all results, surface quality increases with a rising feed rate. In general, the surface quality obtained by milling parts produced using FDM is low, but each manufacturing technique is affected differently by the end milling conditions. Low rotation speed and high feed rates should be preferred to obtain the desired surface quality from FDM printed polyamide parts.","PeriodicalId":51109,"journal":{"name":"Machining Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2021-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42463044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-03DOI: 10.1080/10910344.2021.1971706
Ramazan Hakkı Namlu, B. L. Sadigh, S. E. Kilic
Abstract Ti-6Al-4V is widely used in aerospace, medical and defense industries where materials with superior characteristics are needed. However, Ti-6Al-4V is categorized as a difficult-to-cut material, and machining of this alloy is highly challenging. Ultrasonic Assisted Milling (UAM) is a quite recent method to facilitate the machining of difficult-to-cut materials. This method has numerous advantages over the Conventional Milling (CM) method, such as reduced cutting forces and increased surface quality. Besides, Minimum Quantity Lubrication (MQL) is an alternative cooling method to enhance the process efficiency with respect to conventional cooling methods. Cutting force and surface roughness are essential measures to evaluate the cutting performance of a machining process. However, the simultaneous effects of implementing MQL and ultrasonic vibrations in milling operations are not much researched yet. In this study, the combined effects of UAM and MQL on cutting forces and surface roughness during the machining of Ti-6AL-4V are investigated. Results show that the combination of MQL and UAM enhances the cutting forces in rough cutting operations and the surface roughness in both finish and rough cutting operations significantly compared to conventional processes. Consequently, it is concluded that simultaneous implementation of UAM and MQL enhances overall cutting performance in end-milling operation of Ti-6Al-4V.
{"title":"An experimental investigation on the effects of combined application of ultrasonic assisted milling (UAM) and minimum quantity lubrication (MQL) on cutting forces and surface roughness of Ti-6AL-4V","authors":"Ramazan Hakkı Namlu, B. L. Sadigh, S. E. Kilic","doi":"10.1080/10910344.2021.1971706","DOIUrl":"https://doi.org/10.1080/10910344.2021.1971706","url":null,"abstract":"Abstract Ti-6Al-4V is widely used in aerospace, medical and defense industries where materials with superior characteristics are needed. However, Ti-6Al-4V is categorized as a difficult-to-cut material, and machining of this alloy is highly challenging. Ultrasonic Assisted Milling (UAM) is a quite recent method to facilitate the machining of difficult-to-cut materials. This method has numerous advantages over the Conventional Milling (CM) method, such as reduced cutting forces and increased surface quality. Besides, Minimum Quantity Lubrication (MQL) is an alternative cooling method to enhance the process efficiency with respect to conventional cooling methods. Cutting force and surface roughness are essential measures to evaluate the cutting performance of a machining process. However, the simultaneous effects of implementing MQL and ultrasonic vibrations in milling operations are not much researched yet. In this study, the combined effects of UAM and MQL on cutting forces and surface roughness during the machining of Ti-6AL-4V are investigated. Results show that the combination of MQL and UAM enhances the cutting forces in rough cutting operations and the surface roughness in both finish and rough cutting operations significantly compared to conventional processes. Consequently, it is concluded that simultaneous implementation of UAM and MQL enhances overall cutting performance in end-milling operation of Ti-6Al-4V.","PeriodicalId":51109,"journal":{"name":"Machining Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2021-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46653354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-03DOI: 10.1080/10910344.2021.1971705
Jing Shu, W. Liao, K. Zheng, Amro M. Fikry Hussein Youssef
Abstract Carbon-carbon composites (C/C composites) is typical high temperature resistant material. Therefore it is applied in solid rocket motor (SRM) throat mostly. Because the throat is mostly single piece and mini-batch, which is not suitable for mold forming. Usually, numerical control machining is still the main method. Due to high strength and heterogeneous composites, the machining damage defects are obvious and quality is poor. Thus, from the perspective of C/C composites ablation resistance, rotary ultrasonic machining technology effect on C/C composites surface defects and damage is investigated. Moreover, the influence of ultrasonic vibration on fiber cutting angle and machined surface morphology is analyzed. Meanwhile, based on comparative experiment, fiber pull-out length and surface porosity are presented as characterization parameters. The results show that ultrasonic vibration not only improves fiber cutting angle effectively, but also reduces pores and cracks on machined surfaces. Moreover, it reduces fiber pull-out length by 10%–50% numerically when along fiber milling. When fiber is perpendicular to the cutting direction, the pull-out length becomes shorter. The above study provides a theoretical basis for subsequent machined damage influence on ablation resistance of C/C throat.
{"title":"Surface morphology on carbon fiber composites by rotary ultrasonic milling","authors":"Jing Shu, W. Liao, K. Zheng, Amro M. Fikry Hussein Youssef","doi":"10.1080/10910344.2021.1971705","DOIUrl":"https://doi.org/10.1080/10910344.2021.1971705","url":null,"abstract":"Abstract Carbon-carbon composites (C/C composites) is typical high temperature resistant material. Therefore it is applied in solid rocket motor (SRM) throat mostly. Because the throat is mostly single piece and mini-batch, which is not suitable for mold forming. Usually, numerical control machining is still the main method. Due to high strength and heterogeneous composites, the machining damage defects are obvious and quality is poor. Thus, from the perspective of C/C composites ablation resistance, rotary ultrasonic machining technology effect on C/C composites surface defects and damage is investigated. Moreover, the influence of ultrasonic vibration on fiber cutting angle and machined surface morphology is analyzed. Meanwhile, based on comparative experiment, fiber pull-out length and surface porosity are presented as characterization parameters. The results show that ultrasonic vibration not only improves fiber cutting angle effectively, but also reduces pores and cracks on machined surfaces. Moreover, it reduces fiber pull-out length by 10%–50% numerically when along fiber milling. When fiber is perpendicular to the cutting direction, the pull-out length becomes shorter. The above study provides a theoretical basis for subsequent machined damage influence on ablation resistance of C/C throat.","PeriodicalId":51109,"journal":{"name":"Machining Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2021-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46874245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-03DOI: 10.1080/10910344.2021.1971711
Deepak Sharma, S. Hiremath
Abstract Electric discharge machining (EDM) is a nontraditional machining process based on the thermal erosion of the electrically conductive workpiece and tool electrodes. The product cost manufactured by the EDM process mainly depends on the tooling cost, which comprises the cost of tool material, tool fabrication, and tool maintenance. The properties of tool material affect the machining performance parameters like material removal rate (MRR), tool wear rate (TWR), and surface roughness. The performance parameters are also influenced by the tool geometry, tool fabrication method, and the way by which both tools and workpiece interact with each other. In the EDM process, tool wear is difficult to avoid and high TWR decreases the accuracy of the machined parts. Therefore, to obtain the desired accuracy it is necessary to calculate TWR and provide wear compensation. The tool electrode fabrication method also decides the TWR. Tool electrodes are generally manufactured by metal forming techniques like forging and drawing, other than that, powder metallurgy, additive manufacturing are also being used. The process performance of the tool can be improved by cryogenic treatment and coating of the tool electrodes. This review provides the literature survey about the different types of tools used in the EDM process, methods of fabrication, tool wear types; measurement and compensation techniques.
{"title":"Review on tools and tool wear in EDM","authors":"Deepak Sharma, S. Hiremath","doi":"10.1080/10910344.2021.1971711","DOIUrl":"https://doi.org/10.1080/10910344.2021.1971711","url":null,"abstract":"Abstract Electric discharge machining (EDM) is a nontraditional machining process based on the thermal erosion of the electrically conductive workpiece and tool electrodes. The product cost manufactured by the EDM process mainly depends on the tooling cost, which comprises the cost of tool material, tool fabrication, and tool maintenance. The properties of tool material affect the machining performance parameters like material removal rate (MRR), tool wear rate (TWR), and surface roughness. The performance parameters are also influenced by the tool geometry, tool fabrication method, and the way by which both tools and workpiece interact with each other. In the EDM process, tool wear is difficult to avoid and high TWR decreases the accuracy of the machined parts. Therefore, to obtain the desired accuracy it is necessary to calculate TWR and provide wear compensation. The tool electrode fabrication method also decides the TWR. Tool electrodes are generally manufactured by metal forming techniques like forging and drawing, other than that, powder metallurgy, additive manufacturing are also being used. The process performance of the tool can be improved by cryogenic treatment and coating of the tool electrodes. This review provides the literature survey about the different types of tools used in the EDM process, methods of fabrication, tool wear types; measurement and compensation techniques.","PeriodicalId":51109,"journal":{"name":"Machining Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2021-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48914410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-03DOI: 10.1080/10910344.2021.1971715
K. Biswas, Shirsendu Das, Swarup Paul, B. Doloi
Abstract The Inconel 718 has captured global attention for its huge applications in the aerospace and defense field. However, a limited approach is noticed to investigate this material's responses and morphological features after electrical discharge machining operation. This study wants to offer a more detailed investigating approach, including the analysis of morphological features, recast layer, microhardness, elemental composition, and several textural defects and basic responses. Scanning electron microscopy is used to investigate several textural features, defects, cracks, and recast layers. The findings claim 538 nm–2.168 µm and 14–41 µm variations in crack width and recast thickness, respectively, which increase with pulse current and pulse on-time. However, the low discharge energy can provide better micro-hardness than higher discharge conditions due to having sufficient time for flushing and heat dissipations. The recast surface and the interfaces are, respectively, 7.58%–13.16% and 22.75%–32.74% harder with low discharge condition than the intermediate and higher discharge condition. Moreover, the Energy Dispersive X-ray analysis reported the emigration of 17.81% of carbon and 0.33% of copper from the dielectric and tool during the machining.
{"title":"A morphological and textural analysis of Inconel-718 aerospace alloy processed through electrical discharging machining","authors":"K. Biswas, Shirsendu Das, Swarup Paul, B. Doloi","doi":"10.1080/10910344.2021.1971715","DOIUrl":"https://doi.org/10.1080/10910344.2021.1971715","url":null,"abstract":"Abstract The Inconel 718 has captured global attention for its huge applications in the aerospace and defense field. However, a limited approach is noticed to investigate this material's responses and morphological features after electrical discharge machining operation. This study wants to offer a more detailed investigating approach, including the analysis of morphological features, recast layer, microhardness, elemental composition, and several textural defects and basic responses. Scanning electron microscopy is used to investigate several textural features, defects, cracks, and recast layers. The findings claim 538 nm–2.168 µm and 14–41 µm variations in crack width and recast thickness, respectively, which increase with pulse current and pulse on-time. However, the low discharge energy can provide better micro-hardness than higher discharge conditions due to having sufficient time for flushing and heat dissipations. The recast surface and the interfaces are, respectively, 7.58%–13.16% and 22.75%–32.74% harder with low discharge condition than the intermediate and higher discharge condition. Moreover, the Energy Dispersive X-ray analysis reported the emigration of 17.81% of carbon and 0.33% of copper from the dielectric and tool during the machining.","PeriodicalId":51109,"journal":{"name":"Machining Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2021-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46445887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-04DOI: 10.1080/10910344.2021.1903922
S. M. Ebrahimi, M. Hadad, A. Araee
Abstract The main objective of this study is to initially simulate the cutting process of hardened AISI630 stainless steel to implement thermally enhanced turning followed by hot turning (HT) experiments to demonstrate the effectiveness of the process and identify cutting parameters that would yield the optimum results in terms of sustainability. To precisely predict the chip morphology, as well as the cutting force and tool temperature, 2 D and 3 D FEM analysis, have been used, respectively using AdvantEdge software. The numerical analysis showed that HT in 300 °C causes a reduction of 28% in cutting forces. The tool wear in HT reduces up to 33% in comparison to conventional turning (CT). Furthermore, the relation between cutting force fluctuation and the machined surface roughness has been investigated applying numerical analysis and experimental data. The results revealed that HT in 300 °C reduces the machined surface roughness up to 23%. In addition, it has been observed that HT technique decreases side flow and surface damages in comparison to CT.
{"title":"Sustainable machining of hardened AISI630 stainless steel using thermally enhanced turning technique","authors":"S. M. Ebrahimi, M. Hadad, A. Araee","doi":"10.1080/10910344.2021.1903922","DOIUrl":"https://doi.org/10.1080/10910344.2021.1903922","url":null,"abstract":"Abstract The main objective of this study is to initially simulate the cutting process of hardened AISI630 stainless steel to implement thermally enhanced turning followed by hot turning (HT) experiments to demonstrate the effectiveness of the process and identify cutting parameters that would yield the optimum results in terms of sustainability. To precisely predict the chip morphology, as well as the cutting force and tool temperature, 2 D and 3 D FEM analysis, have been used, respectively using AdvantEdge software. The numerical analysis showed that HT in 300 °C causes a reduction of 28% in cutting forces. The tool wear in HT reduces up to 33% in comparison to conventional turning (CT). Furthermore, the relation between cutting force fluctuation and the machined surface roughness has been investigated applying numerical analysis and experimental data. The results revealed that HT in 300 °C reduces the machined surface roughness up to 23%. In addition, it has been observed that HT technique decreases side flow and surface damages in comparison to CT.","PeriodicalId":51109,"journal":{"name":"Machining Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2021-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/10910344.2021.1903922","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49211764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-04DOI: 10.1080/10910344.2021.1925295
Chuangchuang Yuan, A. Pramanik, A. Basak, C. Prakash, Subramaniam Shankar
Abstract In recent years, demand of titanium alloy (Ti6Al4V) in various industries especially aerospace industries drastically increased. Several exceptional properties of titanium alloy that contribute to its popularity include high compressive and tensile strength, fracture toughness oxidation resistance and high strength-to-weight ratio. However, due to these superior properties, titanium alloys are categorized as hard-to-machine materials. The drilling process is accounted for roughly 40%−60% of material removal processes of an aeronautical product. Drilling processes for titanium alloys are categorized into conventional method (twist drilling) and unconventional method (rotary ultrasonic machining [RUM] drilling, laser drilling and electron discharge machining [EDM] drilling). This research aims to identify mechanisms and limitations of each drilling method applicable on titanium alloys. In addition, processing parameters affecting performance measures of each drilling method are discussed. The main problem associated with conventional twist drilling is extreme processing temperature, resulting in rapid tool wear and extensive burrs formation. These issues cause the cost for titanium alloy drilling to be relatively high as compared with twist drilling of other materials. To minimize these issues, researchers have developed several unconventional drilling methods, aiming to minimize issues found in conventional twist drilling.
{"title":"Drilling of titanium alloy (Ti6Al4V) – a review","authors":"Chuangchuang Yuan, A. Pramanik, A. Basak, C. Prakash, Subramaniam Shankar","doi":"10.1080/10910344.2021.1925295","DOIUrl":"https://doi.org/10.1080/10910344.2021.1925295","url":null,"abstract":"Abstract In recent years, demand of titanium alloy (Ti6Al4V) in various industries especially aerospace industries drastically increased. Several exceptional properties of titanium alloy that contribute to its popularity include high compressive and tensile strength, fracture toughness oxidation resistance and high strength-to-weight ratio. However, due to these superior properties, titanium alloys are categorized as hard-to-machine materials. The drilling process is accounted for roughly 40%−60% of material removal processes of an aeronautical product. Drilling processes for titanium alloys are categorized into conventional method (twist drilling) and unconventional method (rotary ultrasonic machining [RUM] drilling, laser drilling and electron discharge machining [EDM] drilling). This research aims to identify mechanisms and limitations of each drilling method applicable on titanium alloys. In addition, processing parameters affecting performance measures of each drilling method are discussed. The main problem associated with conventional twist drilling is extreme processing temperature, resulting in rapid tool wear and extensive burrs formation. These issues cause the cost for titanium alloy drilling to be relatively high as compared with twist drilling of other materials. To minimize these issues, researchers have developed several unconventional drilling methods, aiming to minimize issues found in conventional twist drilling.","PeriodicalId":51109,"journal":{"name":"Machining Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2021-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/10910344.2021.1925295","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48623362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-18DOI: 10.1080/10910344.2021.1903925
Gaurav Bhakar, Pratik Khandagale, H. Sonawane, S. Joshi
Abstract The uncertainty in the prediction of machining stability increases with the increasing flexibility of the workpiece. The past research showed that the process cannot be stabilized even using the largest pockets in the stability diagrams due to high flexibility of the parts. Therefore, the present research emphasizes extensive experimental analysis where the uncertainty of the stability lobe diagrams was brought into the light, especially in the case of machining of flexible parts. This led to the introduction of a new term “Stability Region Diagram (SRD)” in the present research. The three generalized machining scenarios for chatter-free machining of thin-walled features on low rigidity Ti-6Al-V4 were experimentally analyzed. These include Scenario-I, where workpieces have identical pre-machining stiffness and natural frequency that varies during and after machining. In Scenario-II, workpiece stiffness and natural frequencies vary initially but are identical after machining. In Scenario-III, workpieces have identical pre-machining stiffness and natural frequency but vary during and after machining over central 1/3 part, straddled between bosses. Various machining strategies with an optimum combination of cutting speed-feed-radial depth of cut were developed using stability region diagrams (SRD) to achieve stable machining throughout the length of the cut along the flexible workpiece surface. For Scenario-I and II, stable machining is possible at widths of cut lesser than or equal to the final thickness of workpiece and at a constant spindle speed of 4,000 rpm throughout the length of the workpiece. However, while machining at widths of cut more than the post-machining thickness of the workpiece, the stable machining is possible using a spindle speed ramp-up technique. In the Scenario-III, the surrounding uncut material is found to make machining unstable which can be improved by spindle speed ramp-down technique.
{"title":"Strategy development for chatter-free milling of Ti-6Al-4V thin-walled surfaces using stability region diagram (SRD)","authors":"Gaurav Bhakar, Pratik Khandagale, H. Sonawane, S. Joshi","doi":"10.1080/10910344.2021.1903925","DOIUrl":"https://doi.org/10.1080/10910344.2021.1903925","url":null,"abstract":"Abstract The uncertainty in the prediction of machining stability increases with the increasing flexibility of the workpiece. The past research showed that the process cannot be stabilized even using the largest pockets in the stability diagrams due to high flexibility of the parts. Therefore, the present research emphasizes extensive experimental analysis where the uncertainty of the stability lobe diagrams was brought into the light, especially in the case of machining of flexible parts. This led to the introduction of a new term “Stability Region Diagram (SRD)” in the present research. The three generalized machining scenarios for chatter-free machining of thin-walled features on low rigidity Ti-6Al-V4 were experimentally analyzed. These include Scenario-I, where workpieces have identical pre-machining stiffness and natural frequency that varies during and after machining. In Scenario-II, workpiece stiffness and natural frequencies vary initially but are identical after machining. In Scenario-III, workpieces have identical pre-machining stiffness and natural frequency but vary during and after machining over central 1/3 part, straddled between bosses. Various machining strategies with an optimum combination of cutting speed-feed-radial depth of cut were developed using stability region diagrams (SRD) to achieve stable machining throughout the length of the cut along the flexible workpiece surface. For Scenario-I and II, stable machining is possible at widths of cut lesser than or equal to the final thickness of workpiece and at a constant spindle speed of 4,000 rpm throughout the length of the workpiece. However, while machining at widths of cut more than the post-machining thickness of the workpiece, the stable machining is possible using a spindle speed ramp-up technique. In the Scenario-III, the surrounding uncut material is found to make machining unstable which can be improved by spindle speed ramp-down technique.","PeriodicalId":51109,"journal":{"name":"Machining Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2021-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/10910344.2021.1903925","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42837317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-04DOI: 10.1080/10910344.2021.1903921
Shen-Shun Ying, Shunqi Zhang, Lvgao Lin, Yangyu Wang, R. Schmidt
Abstract Broaching is very efficient for machining complex-shaped slots in turbine disks made of high thermal resistant super-alloys. However, large cutting forces and high thermal flux lead to high tool wear. To reduce the broaching forces, this paper proposes a vibration assisted broaching system, including the main components of a hydraulic horizontal internal broaching machine, an electrohydraulic vibration exciter, a 2-dimensional valve and a control unit. A force measuring structure and vibration signal acquisition module are designed and integrated into the system. By changing the frequency of the active vibration, cutting forces are obtained and analyzed by fast Fourier transformation method. The experimental results show that through the additional imposed vibration, static and dynamic broaching forces are significantly reduced.
{"title":"Experimental investigation on reduction of broaching forces by active external vibrations","authors":"Shen-Shun Ying, Shunqi Zhang, Lvgao Lin, Yangyu Wang, R. Schmidt","doi":"10.1080/10910344.2021.1903921","DOIUrl":"https://doi.org/10.1080/10910344.2021.1903921","url":null,"abstract":"Abstract Broaching is very efficient for machining complex-shaped slots in turbine disks made of high thermal resistant super-alloys. However, large cutting forces and high thermal flux lead to high tool wear. To reduce the broaching forces, this paper proposes a vibration assisted broaching system, including the main components of a hydraulic horizontal internal broaching machine, an electrohydraulic vibration exciter, a 2-dimensional valve and a control unit. A force measuring structure and vibration signal acquisition module are designed and integrated into the system. By changing the frequency of the active vibration, cutting forces are obtained and analyzed by fast Fourier transformation method. The experimental results show that through the additional imposed vibration, static and dynamic broaching forces are significantly reduced.","PeriodicalId":51109,"journal":{"name":"Machining Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2021-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/10910344.2021.1903921","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49458014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-04DOI: 10.1080/10910344.2021.1903923
Preeti Maurya, V. G. S., R. C., B. Shivamurthy
Abstract Elastomers have visco-elastic behavior and are widely used in general utility as well as sophisticated applications. Generally, elastomer components are produced by molding process. But it is not economical for complicated geometrical elastomeric components of small batch size. Hence, machining is an alternative method of the molding. However, high elasticity, low Young’s modulus and low thermal conductivity in addition to the difficulty of holding elastomer component hinder its machining. To address these challenges, in last two decades, cryogenic assisted milling/turning, cryogenic abrasive jet micromachining (CAJM), ultra-high-pressure water jet machining and low-power CO2 laser cutting were reported and noticed that both machining parameters and cryogenic condition affect the quality of the end-product. The structure-property changes on the surface of elastomer due to cryogenic condition helps in improvement of cutting force, erosion rate, chip formation, surface morphology, and reduction in the abrasive particle embedding at the machined surface. In addition to this, cryogenic assisted machining is a safe environmental alternative approach and it reduces the possibility of abrasive contamination at the machined surface. Hence, this article makes a comprehensive review of developments in elastomer machining over the last two decades and discusses the pros and cons of the same.
{"title":"Cryogenic machining of elastomers: a review","authors":"Preeti Maurya, V. G. S., R. C., B. Shivamurthy","doi":"10.1080/10910344.2021.1903923","DOIUrl":"https://doi.org/10.1080/10910344.2021.1903923","url":null,"abstract":"Abstract Elastomers have visco-elastic behavior and are widely used in general utility as well as sophisticated applications. Generally, elastomer components are produced by molding process. But it is not economical for complicated geometrical elastomeric components of small batch size. Hence, machining is an alternative method of the molding. However, high elasticity, low Young’s modulus and low thermal conductivity in addition to the difficulty of holding elastomer component hinder its machining. To address these challenges, in last two decades, cryogenic assisted milling/turning, cryogenic abrasive jet micromachining (CAJM), ultra-high-pressure water jet machining and low-power CO2 laser cutting were reported and noticed that both machining parameters and cryogenic condition affect the quality of the end-product. The structure-property changes on the surface of elastomer due to cryogenic condition helps in improvement of cutting force, erosion rate, chip formation, surface morphology, and reduction in the abrasive particle embedding at the machined surface. In addition to this, cryogenic assisted machining is a safe environmental alternative approach and it reduces the possibility of abrasive contamination at the machined surface. Hence, this article makes a comprehensive review of developments in elastomer machining over the last two decades and discusses the pros and cons of the same.","PeriodicalId":51109,"journal":{"name":"Machining Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2021-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/10910344.2021.1903923","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46125462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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