Six Degrees of Freedom (DOF) robotic manipulators can use non-planar layers to deposit materials in additive manufacturing. Conformal material deposition requires accurately positioning and orienting the deposition tool on non-planar surfaces. Using industrial manipulators to move the deposition tool enables 6 DOF motion and avoids collision between the tool and the pre-existing substrate. Regular articulated industrial robots have high repeatability but do not exhibit high accuracy. Therefore, performing printing that involves small features becomes challenging. In this paper, we present advances in non-planar surface registration with respect to the robot frame, deposition tool calibration, and gap compensation scheme to enable accurate positioning of the tool tip with respect to the non-planar substrate. This enables us to maintain an accurately controlled gap between the tool tip and the underlying surface to allow printing of mesoscale features on curved surfaces. We test the efficacy of the proposed approach by printing a single layer of ink patterns with approximately 130 μm line width on spherical (radius < 1 cm), cylindrical, and planar substrates. We also demonstrate the capability of changing tool orientation enabled by the 6 DOF robotic manipulator and show that adjusting tool orientation is critical in enabling conformal printing on highly curved surfaces. Finally, the gap variation is characterized and accurate control of the gap is demonstrated.
{"title":"Using an Articulated Industrial Robot to Perform Conformal Deposition With Mesoscale Features","authors":"Y. Cai, P. Bhatt, Hangbo Zhao, Satyandra K. Gupta","doi":"10.1115/msec2022-85950","DOIUrl":"https://doi.org/10.1115/msec2022-85950","url":null,"abstract":"\u0000 Six Degrees of Freedom (DOF) robotic manipulators can use non-planar layers to deposit materials in additive manufacturing. Conformal material deposition requires accurately positioning and orienting the deposition tool on non-planar surfaces. Using industrial manipulators to move the deposition tool enables 6 DOF motion and avoids collision between the tool and the pre-existing substrate. Regular articulated industrial robots have high repeatability but do not exhibit high accuracy. Therefore, performing printing that involves small features becomes challenging. In this paper, we present advances in non-planar surface registration with respect to the robot frame, deposition tool calibration, and gap compensation scheme to enable accurate positioning of the tool tip with respect to the non-planar substrate. This enables us to maintain an accurately controlled gap between the tool tip and the underlying surface to allow printing of mesoscale features on curved surfaces. We test the efficacy of the proposed approach by printing a single layer of ink patterns with approximately 130 μm line width on spherical (radius < 1 cm), cylindrical, and planar substrates. We also demonstrate the capability of changing tool orientation enabled by the 6 DOF robotic manipulator and show that adjusting tool orientation is critical in enabling conformal printing on highly curved surfaces. Finally, the gap variation is characterized and accurate control of the gap is demonstrated.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"11 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90929100","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}
Ben Wang, Hong Lu, Qi Liu, Shaojun Wang, Hengchen Pan, Jiashun Dai
Dual-drive feed system (DDFS) is widely used in computer numerical control (CNC) machine tools. In the process of machining, it is necessary to ensure the complete synchronization of the two axes of the feed system, otherwise it will affect the machining accuracy and shorten the life of the machine tool. Due to the structure error of the DDFS and the uneven distribution of the load on the two axes in the process of machining irregular workpiece, there are synchronization errors between the two axes. Therefore, it is of great significance to reduce the synchronization errors by studying the dual-drive synchronous control strategy. In this paper, fuzzy control is introduced into traditional PID synchronous control strategy. Compared with traditional PID control, fuzzy control has the characteristics of high robustness and high control performance. Firstly, the PID model of single-axis servo feed system is established. Then, the master-slave control strategy is selected as the dual-drive synchronous control strategy and the model of master-slave control strategy based on conventional PID (MSCS-CPID) is established. Next, the fuzzy PID control is introduced into the current loop of the servo feed system and the model of master-slave control strategy based on fuzzy PID (MSCS-FPID) is established. The simulation results of the MSCS-CPID and the MSCS-FPID show that the DDFS under the MSCS-FPID has faster response speed and smaller synchronization errors. Moreover, the DDFS under the MSCS-FPID has better synchronization performance after external interference. Experiment confirmed that the synchronization performance of the MSCS-FPID is better than that of the MSCS-CPID.
{"title":"Research on Synchronous Control Strategy of Dual-Drive Feed System Based on Fuzzy PID Control","authors":"Ben Wang, Hong Lu, Qi Liu, Shaojun Wang, Hengchen Pan, Jiashun Dai","doi":"10.1115/msec2022-85458","DOIUrl":"https://doi.org/10.1115/msec2022-85458","url":null,"abstract":"\u0000 Dual-drive feed system (DDFS) is widely used in computer numerical control (CNC) machine tools. In the process of machining, it is necessary to ensure the complete synchronization of the two axes of the feed system, otherwise it will affect the machining accuracy and shorten the life of the machine tool. Due to the structure error of the DDFS and the uneven distribution of the load on the two axes in the process of machining irregular workpiece, there are synchronization errors between the two axes. Therefore, it is of great significance to reduce the synchronization errors by studying the dual-drive synchronous control strategy. In this paper, fuzzy control is introduced into traditional PID synchronous control strategy. Compared with traditional PID control, fuzzy control has the characteristics of high robustness and high control performance. Firstly, the PID model of single-axis servo feed system is established. Then, the master-slave control strategy is selected as the dual-drive synchronous control strategy and the model of master-slave control strategy based on conventional PID (MSCS-CPID) is established. Next, the fuzzy PID control is introduced into the current loop of the servo feed system and the model of master-slave control strategy based on fuzzy PID (MSCS-FPID) is established. The simulation results of the MSCS-CPID and the MSCS-FPID show that the DDFS under the MSCS-FPID has faster response speed and smaller synchronization errors. Moreover, the DDFS under the MSCS-FPID has better synchronization performance after external interference. Experiment confirmed that the synchronization performance of the MSCS-FPID is better than that of the MSCS-CPID.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"25 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79184542","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}
Heebum Chun, Jungsub Kim, Jungsoo Nam, Songhyun Ju, Chabum Lee
In this study, we investigated a novel approach that enables the in-process machining process monitoring at the tool-chip interface (TCI) by utilizing the impedance characteristics of the dielectric coating layer of the cutting tool. This study first analyzes the Nyquist diagram that characterizes the impedance response of a few micrometer-thick dielectric layers coated on the surface of the cutting tool by using an impedance analyzer under various temperature conditions for establishing the relationship between the relative permittivity of the dielectric layer and temperature. Consequently, the impedance of the dielectric layer was subject to change according to given temperature conditions. Thus, under its temperature-dependent impedance characteristics, the machining processes could be in-situ tracked and analyzed by directly probing the localized TCI, the so-called cutting hot spot, during the machining. The current source was implemented with the machining system and the variations of impedance at TCI were monitored during the facing process. As a result, impedance responses were remarkably changed under various machining conditions. The impedance was further characterized under the varying depth of contact and the impedance was decreased as the depth of contact increased. Therefore, the preliminary study demonstrated that an electrical impedance model of the dielectric coating layer may be applied for an in-process machining process monitoring method to analyze and assess the phenomenon of the machining process at the local TCI region. This study is expected to potentially provide utilization in advanced manufacturing to improve final part quality and productivity.
{"title":"In-Process Machining Process Monitoring Method Based on Impedance Model of Dielectric Coating Layer at Tool-Chip Interface","authors":"Heebum Chun, Jungsub Kim, Jungsoo Nam, Songhyun Ju, Chabum Lee","doi":"10.1115/msec2022-85794","DOIUrl":"https://doi.org/10.1115/msec2022-85794","url":null,"abstract":"\u0000 In this study, we investigated a novel approach that enables the in-process machining process monitoring at the tool-chip interface (TCI) by utilizing the impedance characteristics of the dielectric coating layer of the cutting tool. This study first analyzes the Nyquist diagram that characterizes the impedance response of a few micrometer-thick dielectric layers coated on the surface of the cutting tool by using an impedance analyzer under various temperature conditions for establishing the relationship between the relative permittivity of the dielectric layer and temperature. Consequently, the impedance of the dielectric layer was subject to change according to given temperature conditions. Thus, under its temperature-dependent impedance characteristics, the machining processes could be in-situ tracked and analyzed by directly probing the localized TCI, the so-called cutting hot spot, during the machining. The current source was implemented with the machining system and the variations of impedance at TCI were monitored during the facing process. As a result, impedance responses were remarkably changed under various machining conditions. The impedance was further characterized under the varying depth of contact and the impedance was decreased as the depth of contact increased. Therefore, the preliminary study demonstrated that an electrical impedance model of the dielectric coating layer may be applied for an in-process machining process monitoring method to analyze and assess the phenomenon of the machining process at the local TCI region. This study is expected to potentially provide utilization in advanced manufacturing to improve final part quality and productivity.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"56 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87349400","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}
Microsphere photolithography (MPL) has shown promise for the low-cost large-scale manufacturing of infrared (IR) metasurfaces. One challenge of the technique is that the microsphere array needs to be in immediate proximity to the photoresist because of the near-filed effect of the photonic jet. This is typically accomplished by directly transferring the microsphere array onto the photoresist layer. The microspheres are then washed away during the development of the photoresist. While there may be a possibility of recovering, cleaning, and reusing the microspheres, this is not typically done. This work studies the self-assembly of the microspheres on a superstrate which can be reused as a contact mask. The microspheres are fixed to this superstrate to minimize debonding when they are brought into contact with the substrate. IR metasurfaces are fabricated and spectrally characterized. The resonant wavelength of IR metasurfaces is shown to be a good statistical metric for the variation of the patterned surface. The results indicate pressure between the substrate and superstrate is a critical factor in maintaining a minimum gap between the microspheres and photoresist. This work shows a way forward for mask-based microsphere photolithography and provides guidance for future microlens array-based photolithographic techniques.
{"title":"Effects of Pressure on Reusable Self-Assembled Microsphere Masks for Microsphere Photolithography","authors":"Chen Zhu, E. Kinzel","doi":"10.1115/msec2022-85165","DOIUrl":"https://doi.org/10.1115/msec2022-85165","url":null,"abstract":"\u0000 Microsphere photolithography (MPL) has shown promise for the low-cost large-scale manufacturing of infrared (IR) metasurfaces. One challenge of the technique is that the microsphere array needs to be in immediate proximity to the photoresist because of the near-filed effect of the photonic jet. This is typically accomplished by directly transferring the microsphere array onto the photoresist layer. The microspheres are then washed away during the development of the photoresist. While there may be a possibility of recovering, cleaning, and reusing the microspheres, this is not typically done. This work studies the self-assembly of the microspheres on a superstrate which can be reused as a contact mask. The microspheres are fixed to this superstrate to minimize debonding when they are brought into contact with the substrate. IR metasurfaces are fabricated and spectrally characterized. The resonant wavelength of IR metasurfaces is shown to be a good statistical metric for the variation of the patterned surface. The results indicate pressure between the substrate and superstrate is a critical factor in maintaining a minimum gap between the microspheres and photoresist. This work shows a way forward for mask-based microsphere photolithography and provides guidance for future microlens array-based photolithographic techniques.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"28 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77104491","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}
Rana Dabaja, B. Popa, Sun‐Yung Bak, G. Mendonça, M. Banu
Dental implants are a prosthesis for missing teeth that are made to match a natural tooth. Current dental implants experience a high risk of failure in patients that have diseases affecting the oral region. When the patient experiences one or more of these diseases, the interface between the bone and implant is compromised and patients can experience low success rates or insufficient remaining bone structure. The purpose of this research is to create a dental implant technology that is suitable for both healthy and unhealthy patients. In the solutions studied, inducing pores into the Ti6Al4V implant proved to mimic the material properties of natural bone resulting in enhanced osseointegration. We plan to create an innovative solution with enhanced osseointegration that will ensure a gradient in mechanical properties. The complex geometry of the pore-induced dental implant is manufactured using the additive manufacturing method of selective laser melting (SLM). In this research, a functionally graded porous disk was designed using lattice-like pores to mimic the structure of bone. Multiple samples were created with 50-micron pores and printing was studied to test the capabilities of the SLM machine and resolution of the samples. It was found that the parameters play a role in the print resolution of the design. Additional porosity was induced through a keyhole effect during selective melting process.
{"title":"Design and Manufacturing of a Functionally Graded Porous Dental Implant","authors":"Rana Dabaja, B. Popa, Sun‐Yung Bak, G. Mendonça, M. Banu","doi":"10.1115/msec2022-85426","DOIUrl":"https://doi.org/10.1115/msec2022-85426","url":null,"abstract":"\u0000 Dental implants are a prosthesis for missing teeth that are made to match a natural tooth. Current dental implants experience a high risk of failure in patients that have diseases affecting the oral region. When the patient experiences one or more of these diseases, the interface between the bone and implant is compromised and patients can experience low success rates or insufficient remaining bone structure. The purpose of this research is to create a dental implant technology that is suitable for both healthy and unhealthy patients. In the solutions studied, inducing pores into the Ti6Al4V implant proved to mimic the material properties of natural bone resulting in enhanced osseointegration. We plan to create an innovative solution with enhanced osseointegration that will ensure a gradient in mechanical properties. The complex geometry of the pore-induced dental implant is manufactured using the additive manufacturing method of selective laser melting (SLM). In this research, a functionally graded porous disk was designed using lattice-like pores to mimic the structure of bone. Multiple samples were created with 50-micron pores and printing was studied to test the capabilities of the SLM machine and resolution of the samples. It was found that the parameters play a role in the print resolution of the design. Additional porosity was induced through a keyhole effect during selective melting process.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82595625","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}
Rajdeep Singh Devra, Nishkarsh Srivastava, Madhu Vadali, A. Arora
Low-density polyethylene (LDPE) is a soft thermoplastic with extensive application as a packing material such as plastic bags, dispensing bottles, milk pouches, etc. Many LDPE bags are used and dumped in landfills every year, leading to millions of tons of persistent waste. In addition, the recycling of LDPE is of no commercial interest due to its low stiffness, poor mechanical properties, and limited commercial application. In the current work, we attempt to recycle milk pouches made of LDPE to create polymer filaments for fused deposition modeling (FDM), thereby adding value to waste plastic by converting it into high-value 3D printer filament. This research examines the feasibility of reclamation of waste LDPE milk pouches as filament for 3D printers and studies the changes in filament’s chemical and mechanical properties when produced at different temperatures. The waste milk pouches are cleaned thoroughly, shredded, and extruded using a single screw extruder at three nozzle temperatures, i.e., 150°C, 180°C, 210°C. The extruded specimens are analyzed using an optical microscope and scanning electron microscope (SEM) for surface texture. The effect of change in process temperature on flow behaviors is also studied by integrating a current sensor and an encoder. Fourier transform infrared spectroscopy (FTIR) analysis is performed on the filaments and the used LDPE milk pouches to compare the chemical bondings of the polymer. The mechanical properties of the extruded filaments are examined using dynamic mechanical analysis (DMA). The morphological analysis, chemical characterization, and mechanical characterization of prepared filaments are presented. The results show that the chemical bondings are intact after extrusion at all the temperatures examined in this work. The surface texture and the mechanical properties are better at higher temperatures owing to better fluidity and are more suitable for fused deposition modeling. Thus, it is possible to valorize waste LDPE milk pouches by transforming them into filaments for 3D printing.
{"title":"Polymer Filament Extrusion Using LDPE Waste Polymer: Effect of Processing Temperature","authors":"Rajdeep Singh Devra, Nishkarsh Srivastava, Madhu Vadali, A. Arora","doi":"10.1115/msec2022-85586","DOIUrl":"https://doi.org/10.1115/msec2022-85586","url":null,"abstract":"\u0000 Low-density polyethylene (LDPE) is a soft thermoplastic with extensive application as a packing material such as plastic bags, dispensing bottles, milk pouches, etc. Many LDPE bags are used and dumped in landfills every year, leading to millions of tons of persistent waste. In addition, the recycling of LDPE is of no commercial interest due to its low stiffness, poor mechanical properties, and limited commercial application. In the current work, we attempt to recycle milk pouches made of LDPE to create polymer filaments for fused deposition modeling (FDM), thereby adding value to waste plastic by converting it into high-value 3D printer filament. This research examines the feasibility of reclamation of waste LDPE milk pouches as filament for 3D printers and studies the changes in filament’s chemical and mechanical properties when produced at different temperatures. The waste milk pouches are cleaned thoroughly, shredded, and extruded using a single screw extruder at three nozzle temperatures, i.e., 150°C, 180°C, 210°C. The extruded specimens are analyzed using an optical microscope and scanning electron microscope (SEM) for surface texture. The effect of change in process temperature on flow behaviors is also studied by integrating a current sensor and an encoder. Fourier transform infrared spectroscopy (FTIR) analysis is performed on the filaments and the used LDPE milk pouches to compare the chemical bondings of the polymer. The mechanical properties of the extruded filaments are examined using dynamic mechanical analysis (DMA). The morphological analysis, chemical characterization, and mechanical characterization of prepared filaments are presented. The results show that the chemical bondings are intact after extrusion at all the temperatures examined in this work. The surface texture and the mechanical properties are better at higher temperatures owing to better fluidity and are more suitable for fused deposition modeling. Thus, it is possible to valorize waste LDPE milk pouches by transforming them into filaments for 3D printing.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"30 5 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77968397","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}
Jian Mei, Yinhuan Zheng, Hong Lu, Zhangjie Li, Wei Zhang, Di Peng, Huang Lin, Qiong Liu
The multi-support rotary shafting system, represented by the ship propulsion shafting, is widely used in the power transmission device of the ship, and its working condition has a great influence on the operational safety of the ship. Therefore, it is necessary to conduct a dynamic analysis of the ship propulsion shafting. The ship propulsion shafting is used as a prototype to design a transmission shaft system fault detection platform based on the dual-engine parallel transmission mode. In order to accurately simulate the load loaded by the magnetic powder brake in the fault detection platform of the transmission shaft system, the control strategy of the magnetic powder brake loading is studied, including conventional PID control, Smith control, fuzzy Smith control and fuzzy Smith with integral action. The control realizes the ideal control effect of the magnetic powder brake. On the basis of the accurate load control effect, use the Adams software to conduct dynamic simulation analysis on the rigid-flexible hybrid model of the ship propulsion shafting. The dynamic characteristics of the shaft system under normal and fault conditions are studied, the research shows that the occurrence of collision and friction faults will increase the force fluctuation range of the shaft system, the shafting vibration will become more complex, and the characteristic frequency will have a large number of high-multiplication frequencies. The above analysis results have certain significance for the fault analysis of the transmission shaft system.
{"title":"Dynamic Simulation Analysis of Multi-Support Rotary Shaft System","authors":"Jian Mei, Yinhuan Zheng, Hong Lu, Zhangjie Li, Wei Zhang, Di Peng, Huang Lin, Qiong Liu","doi":"10.1115/msec2022-85515","DOIUrl":"https://doi.org/10.1115/msec2022-85515","url":null,"abstract":"\u0000 The multi-support rotary shafting system, represented by the ship propulsion shafting, is widely used in the power transmission device of the ship, and its working condition has a great influence on the operational safety of the ship. Therefore, it is necessary to conduct a dynamic analysis of the ship propulsion shafting. The ship propulsion shafting is used as a prototype to design a transmission shaft system fault detection platform based on the dual-engine parallel transmission mode. In order to accurately simulate the load loaded by the magnetic powder brake in the fault detection platform of the transmission shaft system, the control strategy of the magnetic powder brake loading is studied, including conventional PID control, Smith control, fuzzy Smith control and fuzzy Smith with integral action. The control realizes the ideal control effect of the magnetic powder brake. On the basis of the accurate load control effect, use the Adams software to conduct dynamic simulation analysis on the rigid-flexible hybrid model of the ship propulsion shafting. The dynamic characteristics of the shaft system under normal and fault conditions are studied, the research shows that the occurrence of collision and friction faults will increase the force fluctuation range of the shaft system, the shafting vibration will become more complex, and the characteristic frequency will have a large number of high-multiplication frequencies. The above analysis results have certain significance for the fault analysis of the transmission shaft system.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76661818","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. Cleeman, Alex Bogut, Brijesh Mangrolia, Adeline Ripberger, Arad Maghouli, K. Kate, R. Malhotra
Extrusion-based additive manufacturing of large thermoplastic structures has significant emerging applications. The most popular approach to economically achieving such 3D printing is to increase the polymer flow rate along with the layer height and line width. However, this creates a fundamental compromise between the achievable geometric fidelity and the printing throughput. We explore a Multiplexed Fused Filament Fabrication (MF3) approach in which an array of FFF extruders concurrently prints different sections of the same part using small layer heights and line widths. Mounting all the extruders on one cartesian gantry without individual control of each extruder’s motion enables simple machine construction and control. 3D geometric complexity is realized by rastering the extruder array across the smallest rectangle bounding each 2D layer and by spatially specific deposition via “dynamic” filament retraction/ advancement in the extruders. The dynamic moniker is because, unlike conventional single extruder FFF, the extruder array does not stop during dynamic filament retraction/advancement. This achieves higher throughput at greater resolution without material-intensive overprinting and machining, geometrically-limited throughput of the dual-extruder strategy, cost and geometric limitations of robot-based multiplexing, and the complexity and geometric limitations of previous gantry-based multiplexing efforts. Our experiments reveal the parameters that affect dynamic retraction and advancement, and show a previously unknown coupling between the efficacy of dynamic filament retraction and dynamic filament advancement. We create part-scale thermal simulations to model temperature evolution in the part under the action of multiple concurrently acting extruders, revealing a unique temperature history that can affect bonding and mechanical properties. We show that MF3 can enable resilience to extruder failure by allowing other extruders to take over part fabrication while the damaged extruder is being replaced. We also demonstrate that MF3 enables flexibility in part scale and geometry, i.e., the ability to make multiple smaller parts of similar or distinct geometries in one production run and lesser number of larger parts of similar or distinct geometries in the next production run. Finally, we quantitatively analyze the future potential of MF3 to achieve similar or greater throughput than state-of-the-art Big Area Additive Manufacturing while significantly enhancing the geometric resolution.
{"title":"Multiplexed 3D Printing of Thermoplastics","authors":"J. Cleeman, Alex Bogut, Brijesh Mangrolia, Adeline Ripberger, Arad Maghouli, K. Kate, R. Malhotra","doi":"10.1115/msec2022-80882","DOIUrl":"https://doi.org/10.1115/msec2022-80882","url":null,"abstract":"\u0000 Extrusion-based additive manufacturing of large thermoplastic structures has significant emerging applications. The most popular approach to economically achieving such 3D printing is to increase the polymer flow rate along with the layer height and line width. However, this creates a fundamental compromise between the achievable geometric fidelity and the printing throughput. We explore a Multiplexed Fused Filament Fabrication (MF3) approach in which an array of FFF extruders concurrently prints different sections of the same part using small layer heights and line widths. Mounting all the extruders on one cartesian gantry without individual control of each extruder’s motion enables simple machine construction and control. 3D geometric complexity is realized by rastering the extruder array across the smallest rectangle bounding each 2D layer and by spatially specific deposition via “dynamic” filament retraction/ advancement in the extruders. The dynamic moniker is because, unlike conventional single extruder FFF, the extruder array does not stop during dynamic filament retraction/advancement. This achieves higher throughput at greater resolution without material-intensive overprinting and machining, geometrically-limited throughput of the dual-extruder strategy, cost and geometric limitations of robot-based multiplexing, and the complexity and geometric limitations of previous gantry-based multiplexing efforts. Our experiments reveal the parameters that affect dynamic retraction and advancement, and show a previously unknown coupling between the efficacy of dynamic filament retraction and dynamic filament advancement. We create part-scale thermal simulations to model temperature evolution in the part under the action of multiple concurrently acting extruders, revealing a unique temperature history that can affect bonding and mechanical properties. We show that MF3 can enable resilience to extruder failure by allowing other extruders to take over part fabrication while the damaged extruder is being replaced. We also demonstrate that MF3 enables flexibility in part scale and geometry, i.e., the ability to make multiple smaller parts of similar or distinct geometries in one production run and lesser number of larger parts of similar or distinct geometries in the next production run. Finally, we quantitatively analyze the future potential of MF3 to achieve similar or greater throughput than state-of-the-art Big Area Additive Manufacturing while significantly enhancing the geometric resolution.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"4 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79216736","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}
O. Manyar, Alec Kanyuck, Bharat Deshkulkarni, S. Gupta
In industry, several operations require sheet-like materials to be transported from a loading station to the desired location. Such applications are prevalent in the aerospace and textile industry where composite prepreg sheets or fabrics are placed over a tool or fed to a machine. Using robots for sheet transport operations offers a flexible solution for such highly complex tasks. To create high-quality parts, sheets need to be accurately placed at the correct location. This paper presents automated trajectory planning and control algorithms for a robot to pick up sheets from the input station using suction grippers and, transport and place them over the tool surface. Machine vision is used at the pick location for estimating the sheet pose. Unfortunately, pick-up accuracy is not sufficiently high due to sheet movement during suction-based grasping and localization errors. We employ ideas inspired by visual servo techniques to accurately place the sheet on the tool. Our method uses an Eye-to-Hand camera configuration to align the desired image features with the reference markings on the tool. We introduce a sampling-based Jacobian estimation scheme that can reliably achieve the desired accuracy while minimizing the operation time. Experiments are performed to validate our methodology and compute the placement accuracy on an industrial tool.
{"title":"Visual Servo Based Trajectory Planning for Fast and Accurate Sheet Pick and Place Operations","authors":"O. Manyar, Alec Kanyuck, Bharat Deshkulkarni, S. Gupta","doi":"10.1115/msec2022-85952","DOIUrl":"https://doi.org/10.1115/msec2022-85952","url":null,"abstract":"\u0000 In industry, several operations require sheet-like materials to be transported from a loading station to the desired location. Such applications are prevalent in the aerospace and textile industry where composite prepreg sheets or fabrics are placed over a tool or fed to a machine. Using robots for sheet transport operations offers a flexible solution for such highly complex tasks. To create high-quality parts, sheets need to be accurately placed at the correct location. This paper presents automated trajectory planning and control algorithms for a robot to pick up sheets from the input station using suction grippers and, transport and place them over the tool surface. Machine vision is used at the pick location for estimating the sheet pose. Unfortunately, pick-up accuracy is not sufficiently high due to sheet movement during suction-based grasping and localization errors. We employ ideas inspired by visual servo techniques to accurately place the sheet on the tool. Our method uses an Eye-to-Hand camera configuration to align the desired image features with the reference markings on the tool. We introduce a sampling-based Jacobian estimation scheme that can reliably achieve the desired accuracy while minimizing the operation time. Experiments are performed to validate our methodology and compute the placement accuracy on an industrial tool.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"21 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74936050","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}
To improve the surface properties of fiber-reinforced polymer composites, one method is to employ thermal spray to apply a coating on the composite. For this purpose, it uses a metal mesh serving as an anchor between the composite and the coating to increase adhesion. However, the composite manufacturing covers the metal mesh with resin, and getting an acceptable coating is only possible through an optimum exposure of the metal mesh by sand blasting prior to coating. Therefore, this study aims to develop a computer vision and image processing method to inspect the parts and provide the operator with feedback. Initially, this approach takes the images from a single-view microscope as the inputs, and then it classifies the images into two regions of resin and metal mesh using the Otsu’s adaptive thresholding. Next, it segments the resin areas into distinct connected clusters, and it makes a histogram based on the clusters’ size. Finally, the distribution of the histogram can determine the status of the surface preparation. The state-of-the-art has only examined the sand-blasted composites manually, requiring expertise and experience. This research presents a deterministic method to automate the inspection process efficiently with an inexpensive portable digital microscope. This method is practical, especially when there is a lack of standardized data for machine learning. The experimental results show that the method can get different histograms for various samples, and it can distinguish whether a sample is under-blasted, proper-blasted, or over-blasted successfully. This study also has applications to various fields of manufacturing for defect detection and closed-loop control.
{"title":"A Deterministic Inspection of Surface Preparation for Metalization","authors":"S. Shokri, P. Sedigh, M. Hojjati, Tsz-Ho Kwok","doi":"10.1115/msec2022-85334","DOIUrl":"https://doi.org/10.1115/msec2022-85334","url":null,"abstract":"\u0000 To improve the surface properties of fiber-reinforced polymer composites, one method is to employ thermal spray to apply a coating on the composite. For this purpose, it uses a metal mesh serving as an anchor between the composite and the coating to increase adhesion. However, the composite manufacturing covers the metal mesh with resin, and getting an acceptable coating is only possible through an optimum exposure of the metal mesh by sand blasting prior to coating. Therefore, this study aims to develop a computer vision and image processing method to inspect the parts and provide the operator with feedback. Initially, this approach takes the images from a single-view microscope as the inputs, and then it classifies the images into two regions of resin and metal mesh using the Otsu’s adaptive thresholding. Next, it segments the resin areas into distinct connected clusters, and it makes a histogram based on the clusters’ size. Finally, the distribution of the histogram can determine the status of the surface preparation. The state-of-the-art has only examined the sand-blasted composites manually, requiring expertise and experience. This research presents a deterministic method to automate the inspection process efficiently with an inexpensive portable digital microscope. This method is practical, especially when there is a lack of standardized data for machine learning. The experimental results show that the method can get different histograms for various samples, and it can distinguish whether a sample is under-blasted, proper-blasted, or over-blasted successfully. This study also has applications to various fields of manufacturing for defect detection and closed-loop control.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"53 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75377886","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}
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