This paper presents an analysis of primary chatter under velocity-induced negative process damping in the peripheral outer diameter turning of medium carbon steel. A first-order approximation model of the instant specific cutting force with respect to dynamic cutting speed was established and the slope was defined as the specific process damping coefficient (SPDC) to investigate the negative process damping with respect to cutting speed, depth of cut, and chip thickness. The process damping coefficient was defined as the product of the specific process damping coefficient and chip load. The total system damping coefficient as the sum of the process damping coefficient and structural damping coefficient determines the system stability and predict primary chatter. The SPDCs were obtained through experiments under various speeds, feeds, and depths of cut by using a tool system with force sensors and accelerometers. The SPDCs were insensitive to cutting speeds of 2.5 to 5.5 m/sec and ranged from −1514 and −716 MPa·s/m for feeds per revolution of 0.058 to 0.118 mm, respectively. The higher negative SPDC at smaller chip thickness reduces the limiting stable chip load. Equations for the limiting chip load and limiting depth of cut were derived and validated by experiments. Stability diagrams of limiting chip load and limiting depth with respect to feed per revolution were created to provide guidance on preventing primary chatter.
{"title":"Primary Chatter and Limiting Chip Load in Turning Under Negative Process Damping","authors":"Ming-Jen Hsu, Jiunn-Jyh Wang","doi":"10.1115/msec2022-85293","DOIUrl":"https://doi.org/10.1115/msec2022-85293","url":null,"abstract":"\u0000 This paper presents an analysis of primary chatter under velocity-induced negative process damping in the peripheral outer diameter turning of medium carbon steel. A first-order approximation model of the instant specific cutting force with respect to dynamic cutting speed was established and the slope was defined as the specific process damping coefficient (SPDC) to investigate the negative process damping with respect to cutting speed, depth of cut, and chip thickness. The process damping coefficient was defined as the product of the specific process damping coefficient and chip load. The total system damping coefficient as the sum of the process damping coefficient and structural damping coefficient determines the system stability and predict primary chatter. The SPDCs were obtained through experiments under various speeds, feeds, and depths of cut by using a tool system with force sensors and accelerometers. The SPDCs were insensitive to cutting speeds of 2.5 to 5.5 m/sec and ranged from −1514 and −716 MPa·s/m for feeds per revolution of 0.058 to 0.118 mm, respectively. The higher negative SPDC at smaller chip thickness reduces the limiting stable chip load. Equations for the limiting chip load and limiting depth of cut were derived and validated by experiments. Stability diagrams of limiting chip load and limiting depth with respect to feed per revolution were created to provide guidance on preventing primary chatter.","PeriodicalId":23676,"journal":{"name":"Volume 2: Manufacturing Processes; Manufacturing Systems; Nano/Micro/Meso Manufacturing; Quality and Reliability","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81688495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Baral, Ali Al-Jewad, A. Breunig, J. Ha, P. Groche, Y. Korkolis, B. Kinsey
Elastic waves are generated and propagate when a material undergoes plastic deformation and can be detected by acoustic emission (AE). In this work, AE measurements are obtained during a uniaxial tension (UT) test using a custom-made sensor employing piezoelectric crystals. The UT tests are performed on an MTS machine with two AE sensors clamped on each end of the specimen gage section. A low pass Butterworth filter is designed to attenuate the high frequency noise from the AE signals. Also, full-field strain measurements on the specimen surface are acquired using the 2-D digital image correlation (DIC) method. A typical result from a UT test reveals, as the plastic deformation increases, the AE signals from each sensor increase until they reach a maximum value followed by a drop of signal until the specimen fractures. It is found through interrogation of the DIC images that the maximum amplitude from the AE signals corresponds to the early onset of localized necking. The goal of this work is to implement the UT findings in an actual forming process (e.g., cup drawing) and monitor the event in real time using closed loop control to achieve improved formability.
{"title":"Acoustic Emission Sensors to Monitor Early Onset of Necking During Uniaxial Tension","authors":"M. Baral, Ali Al-Jewad, A. Breunig, J. Ha, P. Groche, Y. Korkolis, B. Kinsey","doi":"10.1115/msec2022-85554","DOIUrl":"https://doi.org/10.1115/msec2022-85554","url":null,"abstract":"\u0000 Elastic waves are generated and propagate when a material undergoes plastic deformation and can be detected by acoustic emission (AE). In this work, AE measurements are obtained during a uniaxial tension (UT) test using a custom-made sensor employing piezoelectric crystals. The UT tests are performed on an MTS machine with two AE sensors clamped on each end of the specimen gage section. A low pass Butterworth filter is designed to attenuate the high frequency noise from the AE signals. Also, full-field strain measurements on the specimen surface are acquired using the 2-D digital image correlation (DIC) method. A typical result from a UT test reveals, as the plastic deformation increases, the AE signals from each sensor increase until they reach a maximum value followed by a drop of signal until the specimen fractures. It is found through interrogation of the DIC images that the maximum amplitude from the AE signals corresponds to the early onset of localized necking. The goal of this work is to implement the UT findings in an actual forming process (e.g., cup drawing) and monitor the event in real time using closed loop control to achieve improved formability.","PeriodicalId":23676,"journal":{"name":"Volume 2: Manufacturing Processes; Manufacturing Systems; Nano/Micro/Meso Manufacturing; Quality and Reliability","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88705886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the era of Industry 4.0, the machining sound has been extensively adopted in tool condition monitoring systems, virtual machining environment, and remote machining solutions. However, only limited attention has been paid to understand how experienced machinists detect tool wear and improper cutting conditions based on their hearing in the real machining environment. This paper aims to experimentally investigate and analyze the auditory perception of CNC operators during the cutting process and their capabilities of detecting unfavorable cutting conditions and faults using their sense of hearing and expertise. The sound in the machining environment was analyzed in the aspect of sound pressure levels (SPL). Optimal positions for sound sample acquisition were determined and audio data was recorded for future analysis. Experimental cutting tests with simulated process faults were conducted, where machinists with varying degrees of experience observed the process, listened to the machining sound and tried to determine whether cutting conditions were normal or if faults occurred. The primary research goal was to analyze how well operators can monitor the process using their various senses and to investigate the role of sound and auditory perceptions of trained professionals in cutting process supervision and monitoring. SPL measurements have shown that the sound pressure varies substantially in the machining environment, which is expected to affect the quality and volume of recorded machining sound depending on microphone positioning. Cutting tests have shown that the machinists use various senses to determine faults in the process, relying most significantly on auditory stimuli, with other factors, such as vibrations or visual examination of the workpiece having a secondary effect in the assessment of cutting process conditions and outcomes.
{"title":"Investigating the Role of Auditory Perception of Cutting Process Conditions in CNC Machining","authors":"K. Jarosz, Yunbo Zhang, R. Liu","doi":"10.1115/msec2022-85804","DOIUrl":"https://doi.org/10.1115/msec2022-85804","url":null,"abstract":"\u0000 In the era of Industry 4.0, the machining sound has been extensively adopted in tool condition monitoring systems, virtual machining environment, and remote machining solutions. However, only limited attention has been paid to understand how experienced machinists detect tool wear and improper cutting conditions based on their hearing in the real machining environment. This paper aims to experimentally investigate and analyze the auditory perception of CNC operators during the cutting process and their capabilities of detecting unfavorable cutting conditions and faults using their sense of hearing and expertise. The sound in the machining environment was analyzed in the aspect of sound pressure levels (SPL). Optimal positions for sound sample acquisition were determined and audio data was recorded for future analysis. Experimental cutting tests with simulated process faults were conducted, where machinists with varying degrees of experience observed the process, listened to the machining sound and tried to determine whether cutting conditions were normal or if faults occurred. The primary research goal was to analyze how well operators can monitor the process using their various senses and to investigate the role of sound and auditory perceptions of trained professionals in cutting process supervision and monitoring. SPL measurements have shown that the sound pressure varies substantially in the machining environment, which is expected to affect the quality and volume of recorded machining sound depending on microphone positioning. Cutting tests have shown that the machinists use various senses to determine faults in the process, relying most significantly on auditory stimuli, with other factors, such as vibrations or visual examination of the workpiece having a secondary effect in the assessment of cutting process conditions and outcomes.","PeriodicalId":23676,"journal":{"name":"Volume 2: Manufacturing Processes; Manufacturing Systems; Nano/Micro/Meso Manufacturing; Quality and Reliability","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88612773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohammad Aman Ullah Al Amin, Yiran Yang, Md Humaun Kobir, Lei Di
Selective laser sintering has become one of the most popular additive manufacturing technologies owing to its great capability of fabricating complex structures with reduced or even eliminated need for the support structure. Meanwhile, an average of 50% to 70% of the consumed powder materials is not directly used for part fabrication. To reduce material waste and enhance material usage efficiency, research studies have been conducted to facilitate the recycling and/or reusing of the waste powder in selective laser sintering. In this research, polyamide 12 powders are studied including virgin powder, waste powder, recycled powder, and mixed powder (with a 30% refresh rate) in terms of their microscopic morphology and material properties. In addition, the location of the powder sampled from the build chamber is also studied for its impact on the powder size and shape. Experimental results show that the average particle size does not change much in different samples, but the standard deviation increases in waste powder. Furthermore, the averaged ultimate tensile strength of test specimens fabricated with virgin powder is around 25% higher than specimens made with mixed powder (30% virgin powder and 70% recycled powder), showing a clear mechanical degradation.
{"title":"Experimental Study of Microscopic Morphology and Material Property for Recycled Polyamide 12 Powder in Selective Laser Sintering","authors":"Mohammad Aman Ullah Al Amin, Yiran Yang, Md Humaun Kobir, Lei Di","doi":"10.1115/msec2022-85618","DOIUrl":"https://doi.org/10.1115/msec2022-85618","url":null,"abstract":"\u0000 Selective laser sintering has become one of the most popular additive manufacturing technologies owing to its great capability of fabricating complex structures with reduced or even eliminated need for the support structure. Meanwhile, an average of 50% to 70% of the consumed powder materials is not directly used for part fabrication. To reduce material waste and enhance material usage efficiency, research studies have been conducted to facilitate the recycling and/or reusing of the waste powder in selective laser sintering. In this research, polyamide 12 powders are studied including virgin powder, waste powder, recycled powder, and mixed powder (with a 30% refresh rate) in terms of their microscopic morphology and material properties. In addition, the location of the powder sampled from the build chamber is also studied for its impact on the powder size and shape. Experimental results show that the average particle size does not change much in different samples, but the standard deviation increases in waste powder. Furthermore, the averaged ultimate tensile strength of test specimens fabricated with virgin powder is around 25% higher than specimens made with mixed powder (30% virgin powder and 70% recycled powder), showing a clear mechanical degradation.","PeriodicalId":23676,"journal":{"name":"Volume 2: Manufacturing Processes; Manufacturing Systems; Nano/Micro/Meso Manufacturing; Quality and Reliability","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75290282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ajanta Saha, Sarath Gopalakrishnan, J. Waimin, S. Sedaghat, Ye Mi, N. Glassmaker, Mukkerem Cakmak, A. Shakouri, R. Rahimi, Muhammad A. Alam
Roll-to-Roll (R2R) process is well suited for manufacturing low cost, miniaturized, solid contact Ion-selective electrodes (ISEs) of potentiometric sensors to be used for continuous monitoring of various analytes in environmental, industrial, and health-care applications. It is presumed that the intrinsic thickness variability of the R2R process would limit the accuracy of the ISE-based sensors and would make them inferior to sensors fabricated by higher precision manufacturing processes. Instead, in this paper we propose to use the intrinsic variability of R2R process as a “resource” to achieve high-accuracy sensing even when the sensors are operated in uncontrolled field conditions. This is achieved by applying a fundamentally new physics-guided statistical approach involving: (i) ‘Self calibration’ where we calculate temperature from differential measurement of the ISEs induced by R2R variability to calibrate the sensors in uncontrolled temperature condition, and (ii) ‘Quorum sensing’ where we use a collection of R2R manufactured sensors to estimate the true concentration considering credibility of each sensor calculated by Bayesian Maximum Likelihood Estimation method. With these two new techniques, we demonstrate the use of “low-precision” R2R sensors to measure nitrate concentration of an agricultural field continuously over a period of 15 days within 10% of the ground-truth measured by the traditional high-precision commercial nitrate sensor.
{"title":"Embrace the Imperfection: How Intrinsic Variability of Roll-to-Roll Manufactured Environmental Sensors Enable Self-Calibrating, High-Precision Quorum Sensing","authors":"Ajanta Saha, Sarath Gopalakrishnan, J. Waimin, S. Sedaghat, Ye Mi, N. Glassmaker, Mukkerem Cakmak, A. Shakouri, R. Rahimi, Muhammad A. Alam","doi":"10.1115/msec2022-84878","DOIUrl":"https://doi.org/10.1115/msec2022-84878","url":null,"abstract":"\u0000 Roll-to-Roll (R2R) process is well suited for manufacturing low cost, miniaturized, solid contact Ion-selective electrodes (ISEs) of potentiometric sensors to be used for continuous monitoring of various analytes in environmental, industrial, and health-care applications. It is presumed that the intrinsic thickness variability of the R2R process would limit the accuracy of the ISE-based sensors and would make them inferior to sensors fabricated by higher precision manufacturing processes. Instead, in this paper we propose to use the intrinsic variability of R2R process as a “resource” to achieve high-accuracy sensing even when the sensors are operated in uncontrolled field conditions. This is achieved by applying a fundamentally new physics-guided statistical approach involving: (i) ‘Self calibration’ where we calculate temperature from differential measurement of the ISEs induced by R2R variability to calibrate the sensors in uncontrolled temperature condition, and (ii) ‘Quorum sensing’ where we use a collection of R2R manufactured sensors to estimate the true concentration considering credibility of each sensor calculated by Bayesian Maximum Likelihood Estimation method. With these two new techniques, we demonstrate the use of “low-precision” R2R sensors to measure nitrate concentration of an agricultural field continuously over a period of 15 days within 10% of the ground-truth measured by the traditional high-precision commercial nitrate sensor.","PeriodicalId":23676,"journal":{"name":"Volume 2: Manufacturing Processes; Manufacturing Systems; Nano/Micro/Meso Manufacturing; Quality and Reliability","volume":"215 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90024599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Asghar Rezasoltani, Matthew Crocker, J. Rice, Avery Black
The robotic incremental sheet forming process, including the CAD design, programming, and robotic manufacturing, as performed to form the school’s Big Red Mascot shape on a flat 30″ × 30″, gauge 26, AL 3003 sheet is explained in this research. This paper explains the technics used in the design, programming, and manufacturing processes to avoid or minimize typical ISF manufacturing problems such as spring-back effect, pillow effect, orange peel effect, and maximum wall angles. The quality of the forming process was investigated visually and by measuring the surface quality and geometric accuracy using a surface tester machine and a 3D scanner. The novelty of the work is the ISF manufacturing of the complex Big Red shape compared to the simple shapes reported in other research, as well as the experimental and measurement setup used in this research.
{"title":"Incremental Sheet Forming of the WKU Big Red Mascot","authors":"Asghar Rezasoltani, Matthew Crocker, J. Rice, Avery Black","doi":"10.1115/msec2022-78600","DOIUrl":"https://doi.org/10.1115/msec2022-78600","url":null,"abstract":"\u0000 The robotic incremental sheet forming process, including the CAD design, programming, and robotic manufacturing, as performed to form the school’s Big Red Mascot shape on a flat 30″ × 30″, gauge 26, AL 3003 sheet is explained in this research. This paper explains the technics used in the design, programming, and manufacturing processes to avoid or minimize typical ISF manufacturing problems such as spring-back effect, pillow effect, orange peel effect, and maximum wall angles.\u0000 The quality of the forming process was investigated visually and by measuring the surface quality and geometric accuracy using a surface tester machine and a 3D scanner. The novelty of the work is the ISF manufacturing of the complex Big Red shape compared to the simple shapes reported in other research, as well as the experimental and measurement setup used in this research.","PeriodicalId":23676,"journal":{"name":"Volume 2: Manufacturing Processes; Manufacturing Systems; Nano/Micro/Meso Manufacturing; Quality and Reliability","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85994444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Under the fourth industrial revolution (Industry 4.0), Augmented Reality (AR) provides new affordances for a variety of applications, such as AR-based human-robot interaction, virtual assembly assistance, and workforce virtual training. The see-through head-mounted displays (STHMDs), based on either optical see-through or video see-through technologies, are the primary AR device to augment the visual perception of the real environment with computer-generated contents through a hand-free headset. Specifically, the video see-through STHMDs process the superimposing of the real environment and virtual contents based on the digital images and output it to users, while optical see-through STHMDs display virtual contents through the optics-based near-eyes display with users’ normal view of the real scene kept. For both types of AR devices, the accuracy of visualization is essential. For example, in AR-based human-robot interaction, the inaccurate rendering of 3D virtual objects with respect to the real environment, will lead to users’ mistaking operations, and therefore, causes an invalid tool path planning result. In spite of many works related to system calibration and error reduction for optical see-through STHMDs, there are few efforts at figuring out the nature and factors of those errors in video see-through STHMDs. In this paper, taking consumer-available AR video see-through STHMDs as an example, we identify error sources of registration and build a mathematical model of the display progress to describe the error propagation in the stereo video see-through systems. Then, based on the mathematical model of the system, the sensitivity of each error source to the final registration error is analyzed. Finally, possible solutions of error correction are suggested and summarized in the general video see-through STHMDs.
{"title":"Visualization Error Analysis for Augmented Reality Stereo Video See-Through Head-Mounted Displays in Industry 4.0 Applications","authors":"Wenhao Yang, Yunbo Zhang","doi":"10.1115/msec2022-85440","DOIUrl":"https://doi.org/10.1115/msec2022-85440","url":null,"abstract":"\u0000 Under the fourth industrial revolution (Industry 4.0), Augmented Reality (AR) provides new affordances for a variety of applications, such as AR-based human-robot interaction, virtual assembly assistance, and workforce virtual training. The see-through head-mounted displays (STHMDs), based on either optical see-through or video see-through technologies, are the primary AR device to augment the visual perception of the real environment with computer-generated contents through a hand-free headset. Specifically, the video see-through STHMDs process the superimposing of the real environment and virtual contents based on the digital images and output it to users, while optical see-through STHMDs display virtual contents through the optics-based near-eyes display with users’ normal view of the real scene kept. For both types of AR devices, the accuracy of visualization is essential. For example, in AR-based human-robot interaction, the inaccurate rendering of 3D virtual objects with respect to the real environment, will lead to users’ mistaking operations, and therefore, causes an invalid tool path planning result. In spite of many works related to system calibration and error reduction for optical see-through STHMDs, there are few efforts at figuring out the nature and factors of those errors in video see-through STHMDs. In this paper, taking consumer-available AR video see-through STHMDs as an example, we identify error sources of registration and build a mathematical model of the display progress to describe the error propagation in the stereo video see-through systems. Then, based on the mathematical model of the system, the sensitivity of each error source to the final registration error is analyzed. Finally, possible solutions of error correction are suggested and summarized in the general video see-through STHMDs.","PeriodicalId":23676,"journal":{"name":"Volume 2: Manufacturing Processes; Manufacturing Systems; Nano/Micro/Meso Manufacturing; Quality and Reliability","volume":"161 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77211568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Sheikh-Ahmad, R. U. Rehman, S. Deveci, F. Almaskari
In this study we investigate the effect of material temperatures on material flow and weld quality in the friction stir welding of bi-modal high density polyethylene (HDPE). The heat input to the process was controlled by varying the tool rotational speed, welding speed and the material initial temperature. Preheating of the HDPE blanks on the bottom surface of the weld was incorporated in order to increase the material flow in this relatively colder region. Temperatures on the boundary surfaces of the HDPE blanks were measured using an infrared camera and thermocouples. Material flow patterns were observed by welding two different colors of the polymer blanks, white on the advancing side and black on the retreating side. Joint quality was assessed using optical microscopy and joint strength was measured by tensile testing. It was found that material temperatures greatly affect the material flow in the weld zone, which in turn affects the tendency to form defects and the overall joint quality. High joint efficiencies and large elongations in excess of 100% were obtained when the material temperatures across the thickness were in excess of 100 °C.
{"title":"Process Temperatures and Material Flow in Friction Stir Welding of High Density Polyethylene (HDPE)","authors":"J. Sheikh-Ahmad, R. U. Rehman, S. Deveci, F. Almaskari","doi":"10.1115/msec2022-85464","DOIUrl":"https://doi.org/10.1115/msec2022-85464","url":null,"abstract":"\u0000 In this study we investigate the effect of material temperatures on material flow and weld quality in the friction stir welding of bi-modal high density polyethylene (HDPE). The heat input to the process was controlled by varying the tool rotational speed, welding speed and the material initial temperature. Preheating of the HDPE blanks on the bottom surface of the weld was incorporated in order to increase the material flow in this relatively colder region. Temperatures on the boundary surfaces of the HDPE blanks were measured using an infrared camera and thermocouples. Material flow patterns were observed by welding two different colors of the polymer blanks, white on the advancing side and black on the retreating side. Joint quality was assessed using optical microscopy and joint strength was measured by tensile testing. It was found that material temperatures greatly affect the material flow in the weld zone, which in turn affects the tendency to form defects and the overall joint quality. High joint efficiencies and large elongations in excess of 100% were obtained when the material temperatures across the thickness were in excess of 100 °C.","PeriodicalId":23676,"journal":{"name":"Volume 2: Manufacturing Processes; Manufacturing Systems; Nano/Micro/Meso Manufacturing; Quality and Reliability","volume":"116 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84922895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study highlighted the effect of alloying elements in Al alloy on the interfacial microstructure, and the corresponding fracture behaviour of the Al alloy/steel inertia friction welded joint by selectively adopting two types of Al alloys. A strong texture of <111>//radial direction was formed on the Al alloy side in both types of joints, while no obvious changes were identified on the steel side. Different types of intermetallic compounds (IMCs) were formed at the weld interface. In the Al-Mg-Si alloy/steel joint produced at a low heat input, the interfacial microstructure was composed of a nanoscale amorphous layer and partially crystallised layer, while it turned into a fully crystallised Fe2Al5 phase with Si enriched when the heat input was enhanced. In the Al-Cu alloy/steel joint, Cu was enriched at the weld interface, with the possible formation of Fe-Al-Cu based IMCs. Moreover, a two-layered structure of IMC with different compositions of Cu appeared when the joint was prepared at a high heat input. Such distinct interfacial microstructure caused different fracture behaviours of joints. An interfacial reaction layer less than 130 nm thick led to the failure of Al alloy rather than the weld interface which easily happened at a thicker IMC.
{"title":"Effect of Alloying Elements of Al Alloy on the Interfacial Microstructure and Fracture Behaviour of Al Alloy/Steel Inertia Friction Welded Joint: A Comparative Study","authors":"Hong Ma, Peihao Geng, G. Qin","doi":"10.1115/msec2022-85196","DOIUrl":"https://doi.org/10.1115/msec2022-85196","url":null,"abstract":"\u0000 The present study highlighted the effect of alloying elements in Al alloy on the interfacial microstructure, and the corresponding fracture behaviour of the Al alloy/steel inertia friction welded joint by selectively adopting two types of Al alloys. A strong texture of <111>//radial direction was formed on the Al alloy side in both types of joints, while no obvious changes were identified on the steel side. Different types of intermetallic compounds (IMCs) were formed at the weld interface. In the Al-Mg-Si alloy/steel joint produced at a low heat input, the interfacial microstructure was composed of a nanoscale amorphous layer and partially crystallised layer, while it turned into a fully crystallised Fe2Al5 phase with Si enriched when the heat input was enhanced. In the Al-Cu alloy/steel joint, Cu was enriched at the weld interface, with the possible formation of Fe-Al-Cu based IMCs. Moreover, a two-layered structure of IMC with different compositions of Cu appeared when the joint was prepared at a high heat input. Such distinct interfacial microstructure caused different fracture behaviours of joints. An interfacial reaction layer less than 130 nm thick led to the failure of Al alloy rather than the weld interface which easily happened at a thicker IMC.","PeriodicalId":23676,"journal":{"name":"Volume 2: Manufacturing Processes; Manufacturing Systems; Nano/Micro/Meso Manufacturing; Quality and Reliability","volume":"217 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86499063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Richie Garg, Harish Singh Dhami, Priti Ranjan Panda, K. Viswanathan
Metal additive manufacturing (AM) enables the production of non-trivial geometries and intricate internal structures. Directed energy deposition (DED) is one such AM process that has the inherent advantage of producing multi-material components on complex pre-existing geometries. Significant recent interest in DED processes has been driven by the need for inexpensive powders and potential material recycling. In this work, we explore the possibility of using non-standard arbitrary shaped metal powders within the DED process. A standard numerical model, comprising a three-dimensional viscous, compressible, turbulent solver with two-way discrete phase coupling is employed to understand the mechanics of gas-driven non-spherical powder flow. Spatial distributions of non-spherical powder on a set of pre-existing geometric features (e.g., corners, curved surfaces) are evaluateds and compared with standard spherical powders. The effect of particle collisions on the substrate is evaluated and corresponding density distributions are quantified. Non-spherical particles are generally found to exhibit higher velocities, and greater deposition track width, compared to spherical particles. Our simulations also reveal the effect of particle shape on their flow properties and final powder density. Using a custom-built DED configuration, we present preliminary experimental results of single-track depositions using both spherical and non-spherical powder particles. Based on our findings, we make a case for the use of non-spherical powders for DED applications.
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