Aluminum recycling requires less energy and releases fewer greenhouse emissions than primary production from naturally occurring ores; however, a significant fraction of the furnace charge is lost to dross generation during remelting. In this article, we use an electric furnace to remelt clean aluminum sheet and machining chip process scrap of varying thickness, surface roughness, and composition. The metal recovery results show that magnesium-containing alloys (e.g., 2xxx, 5xxx, 6xxx, and 7xxx alloys) accelerate dross generation and lower metal recovery. This is likely due to magnesium having a higher reactivity than aluminum, with the magnesium content detected in the dross (using Energy-dispersive X-ray spectroscopy) greater than the magnesium content in the alloy. Metal recovery decreased when remelting thinner scrap. Metal recovery for clean machining chips was lower than for aluminum sheet scrap of the same thickness and composition. This disparity was likely due to the greater surface roughness of the machining chips, which will increase the surface area for oxidation and potentially the wetting of the oxide by the Wenzel effect. The decreased metal recovery for scratch brushed aluminum sheets confirmed the effect of surface roughness. Subsequently, a “squeeze” cutting tool was designed and manufactured, which smooths the otherwise rough back-side of the machining chips. These smoother machining chips exhibited increased metal recovery during remelting.
{"title":"The Effect of Composition, Geometry and a Novel Tool Design on Metal Recovery During Aluminum Process Scrap Remelting","authors":"Jiankan Liao, Ashvin Sharma, Daniel Cooper","doi":"10.1115/msec2022-84900","DOIUrl":"https://doi.org/10.1115/msec2022-84900","url":null,"abstract":"\u0000 Aluminum recycling requires less energy and releases fewer greenhouse emissions than primary production from naturally occurring ores; however, a significant fraction of the furnace charge is lost to dross generation during remelting. In this article, we use an electric furnace to remelt clean aluminum sheet and machining chip process scrap of varying thickness, surface roughness, and composition. The metal recovery results show that magnesium-containing alloys (e.g., 2xxx, 5xxx, 6xxx, and 7xxx alloys) accelerate dross generation and lower metal recovery. This is likely due to magnesium having a higher reactivity than aluminum, with the magnesium content detected in the dross (using Energy-dispersive X-ray spectroscopy) greater than the magnesium content in the alloy. Metal recovery decreased when remelting thinner scrap. Metal recovery for clean machining chips was lower than for aluminum sheet scrap of the same thickness and composition. This disparity was likely due to the greater surface roughness of the machining chips, which will increase the surface area for oxidation and potentially the wetting of the oxide by the Wenzel effect. The decreased metal recovery for scratch brushed aluminum sheets confirmed the effect of surface roughness. Subsequently, a “squeeze” cutting tool was designed and manufactured, which smooths the otherwise rough back-side of the machining chips. These smoother machining chips exhibited increased metal recovery during remelting.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"66 2 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88468571","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 many additive manufacturing processes, surface roughness is a critical quality concern. Due to the nature of the layer-by-layer manufacturing process, the pattern of surface roughness depends on the location on the surface, i.e., the layer number and the location within each layer. Adequate description of the surface roughness enables us to develop effective post-processing plans, reveal the root causes of the roughness, and generate accurate compensation schemes. In this work, we propose a three-step surface roughness characterization method (SRCM). This method is based on the dense point cloud data generated from the surface scan of additively manufactured products. First, we use a double kernel smoothing spatial variogram estimator to represent the heterogeneous roughness property at different surface locations. Second, we extract the magnitude and scale of surface roughness from the estimated variogram. Third, we use Gaussian Process to build a roughness map on the entire surface based on the roughness characterization on these sampled points. The SRCM is demonstrated from a high-density 3D scan of a cylindrical product fabricated by a wire-arc additive manufacturing process. It shows that our approach serves as an effective tool to infer the roughness map from the 3D point cloud data. In the end, we will briefly discuss how to use the inferred roughness map to develop an optimal surface smoothing method.
{"title":"A Surface Roughness Characterization Method for Additively Manufactured Products","authors":"Andi Wang, D. Jafari, T. Vaneker, Qiang Huang","doi":"10.1115/msec2022-85697","DOIUrl":"https://doi.org/10.1115/msec2022-85697","url":null,"abstract":"\u0000 In many additive manufacturing processes, surface roughness is a critical quality concern. Due to the nature of the layer-by-layer manufacturing process, the pattern of surface roughness depends on the location on the surface, i.e., the layer number and the location within each layer. Adequate description of the surface roughness enables us to develop effective post-processing plans, reveal the root causes of the roughness, and generate accurate compensation schemes.\u0000 In this work, we propose a three-step surface roughness characterization method (SRCM). This method is based on the dense point cloud data generated from the surface scan of additively manufactured products. First, we use a double kernel smoothing spatial variogram estimator to represent the heterogeneous roughness property at different surface locations. Second, we extract the magnitude and scale of surface roughness from the estimated variogram. Third, we use Gaussian Process to build a roughness map on the entire surface based on the roughness characterization on these sampled points.\u0000 The SRCM is demonstrated from a high-density 3D scan of a cylindrical product fabricated by a wire-arc additive manufacturing process. It shows that our approach serves as an effective tool to infer the roughness map from the 3D point cloud data. In the end, we will briefly discuss how to use the inferred roughness map to develop an optimal surface smoothing method.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"46 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77177011","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}
Min Hu, Hong Lu, Qi Liu, Jiashun Dai, Ben Wang, Shaojun Wang
Due to the principle of driving at gravity center (DGC), Gantry mobile-type dual-drive machines (GMDMs) are widely used in automatic equipment. The dynamic characteristics of GMDMs have a large influence on the machining quality, efficiency and processing performance of the machine tool. According to the existing research on the dynamic characteristics of GMDMs, it can be found that the dynamic characteristics of the machine tool can be influenced by the feed parameters. So, combined with the research content of the subject, the influence of feed speed on the dynamic characteristics of machine tools under different accelerations is studied. In this paper, based on the law of conservation energy, the dynamic model of GMDMs is established. Then, the accuracy and correctness of the dynamic model are verified through theoretical calculations combined with static hammering experiments, this can provide strong theoretical support for subsequent experiments. And the influence of feed speed under different motor acceleration on the dynamic characteristics of the dual-drive system was studied by two experiments. This study provides a method for analyzing the effect of the feed parameters on the dynamic characteristics of the machine tool under different accelerations.
{"title":"Analysis of Dynamic Parameter for Gantry Mobile-Type Dual-Drive Machine","authors":"Min Hu, Hong Lu, Qi Liu, Jiashun Dai, Ben Wang, Shaojun Wang","doi":"10.1115/msec2022-85526","DOIUrl":"https://doi.org/10.1115/msec2022-85526","url":null,"abstract":"\u0000 Due to the principle of driving at gravity center (DGC), Gantry mobile-type dual-drive machines (GMDMs) are widely used in automatic equipment. The dynamic characteristics of GMDMs have a large influence on the machining quality, efficiency and processing performance of the machine tool. According to the existing research on the dynamic characteristics of GMDMs, it can be found that the dynamic characteristics of the machine tool can be influenced by the feed parameters. So, combined with the research content of the subject, the influence of feed speed on the dynamic characteristics of machine tools under different accelerations is studied. In this paper, based on the law of conservation energy, the dynamic model of GMDMs is established. Then, the accuracy and correctness of the dynamic model are verified through theoretical calculations combined with static hammering experiments, this can provide strong theoretical support for subsequent experiments. And the influence of feed speed under different motor acceleration on the dynamic characteristics of the dual-drive system was studied by two experiments. This study provides a method for analyzing the effect of the feed parameters on the dynamic characteristics of the machine tool under different accelerations.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"125 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78458464","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}
4D printing has spurred growing interests since its recent emergence, as it enables the fabrication of dynamic structures with reconfigurability over time when exposed to external stimuli, which is not feasible using 3D printing. The current literature on 4D printing is mainly focused on developing new materials and investigating the time-evolving properties of the printed parts, whereas the influences of process parameters on stimuli-response behaviors of 4D printed parts are not adequately explored, especially under cyclic loadings. In this study, experimental analyses are conducted to investigate the effects of infill strategies and stimulus conditions on the shape memory properties of 4D printed thermo-responsive parts. Specifically, cyclic thermo-mechanical tests are performed under different operating temperatures to investigate the shape programmability and recovery characteristic of specimens printed with various infill patterns. The results indicate that specimens printed with the rectilinear pattern exhibit better shape programmability under cyclic thermo-mechanical loadings than polygonal patterns. In addition, the decrease in shape fixity ratios over multiple cycles is also observed for all considered infill patterns. The comparative studies suggest that the increase in operating temperature within the vicinity of the material’s glass transition temperature can improve the cyclic shape memory property.
{"title":"Shape Memory Properties of 4D Printed Parts Under Cyclic Loading: Effects of Infill Characteristics and Stimulus Conditions","authors":"Muyue Han, Jing Zhao, Lin Li, Miao Tan","doi":"10.1115/msec2022-85825","DOIUrl":"https://doi.org/10.1115/msec2022-85825","url":null,"abstract":"\u0000 4D printing has spurred growing interests since its recent emergence, as it enables the fabrication of dynamic structures with reconfigurability over time when exposed to external stimuli, which is not feasible using 3D printing. The current literature on 4D printing is mainly focused on developing new materials and investigating the time-evolving properties of the printed parts, whereas the influences of process parameters on stimuli-response behaviors of 4D printed parts are not adequately explored, especially under cyclic loadings. In this study, experimental analyses are conducted to investigate the effects of infill strategies and stimulus conditions on the shape memory properties of 4D printed thermo-responsive parts. Specifically, cyclic thermo-mechanical tests are performed under different operating temperatures to investigate the shape programmability and recovery characteristic of specimens printed with various infill patterns. The results indicate that specimens printed with the rectilinear pattern exhibit better shape programmability under cyclic thermo-mechanical loadings than polygonal patterns. In addition, the decrease in shape fixity ratios over multiple cycles is also observed for all considered infill patterns. The comparative studies suggest that the increase in operating temperature within the vicinity of the material’s glass transition temperature can improve the cyclic shape memory property.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"47 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75377630","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}
Owing to its superior durability, good biocompatibility, and high recycling capability, high-density polyethylene (HDPE) has been widely applied into making prosthetic implants, liquid permeable membranes, corrosion-resistant pipes, etc., and gains its popularity in packaging, consumer goods, and chemical industries. Injection molding and blow molding are two most common conventional processes of making HDPE products. These conventional processes, however, are considered time-consuming and labor-intensive since molds are usually needed prior to fabricating parts. Moreover, manufacturing complex-structured parts (such as lattice and cellular structures) is a challenge for these conventional manufacturing processes. Facing these problems, it is crucial to find a time- and labor-saving process, which can be used to manufacture complicated structures in a cost-effective way. Additive manufacturing (AM) is such a process that needs no mold and is more affordable to create complex and highly customized parts. Among all types of AM processes, fused deposition modeling (FDM), which is primarily designed for thermoplastic materials, seemed to be a benevolent process for fabricating HDPE parts. Based on reported publications, however, it is difficult to print HDPE materials using FDM due to the problems of warping, shrinking, and weak bonding between printed HDPE parts and the substrate. In addition, the FDM-printed HDPE parts can demonstrate defects of porosities and delamination. To improve the printability of FDM, we conducted preliminary experiments and optimized processing parameters. For the first time, we added carbon fiber (CF) into HDPE to make CF-reinforced HDPE composites (CF-HDPE) using FDM and investigated the effects of CF on part quality, microstructure characteristics, and mechanical properties (including tensile properties and dynamic mechanical properties) of CF-reinforced HDPE composites. Experimental results show that the addition of CF was beneficial for not only improving the printability of FDM and quality of printed composite parts, but also for enhancing mechanical properties (such as Young’s Modulus and ultimate tensile strength) of the parts.
{"title":"Fused Deposition Modeling of Carbon Fiber Reinforced High-Density Polyethylene: Effects on Microstructure and Mechanical Properties","authors":"P. Pandit, Chang Liu, Giancarlo Corti, Yingbin Hu","doi":"10.1115/msec2022-85702","DOIUrl":"https://doi.org/10.1115/msec2022-85702","url":null,"abstract":"\u0000 Owing to its superior durability, good biocompatibility, and high recycling capability, high-density polyethylene (HDPE) has been widely applied into making prosthetic implants, liquid permeable membranes, corrosion-resistant pipes, etc., and gains its popularity in packaging, consumer goods, and chemical industries. Injection molding and blow molding are two most common conventional processes of making HDPE products. These conventional processes, however, are considered time-consuming and labor-intensive since molds are usually needed prior to fabricating parts. Moreover, manufacturing complex-structured parts (such as lattice and cellular structures) is a challenge for these conventional manufacturing processes. Facing these problems, it is crucial to find a time- and labor-saving process, which can be used to manufacture complicated structures in a cost-effective way. Additive manufacturing (AM) is such a process that needs no mold and is more affordable to create complex and highly customized parts. Among all types of AM processes, fused deposition modeling (FDM), which is primarily designed for thermoplastic materials, seemed to be a benevolent process for fabricating HDPE parts. Based on reported publications, however, it is difficult to print HDPE materials using FDM due to the problems of warping, shrinking, and weak bonding between printed HDPE parts and the substrate. In addition, the FDM-printed HDPE parts can demonstrate defects of porosities and delamination. To improve the printability of FDM, we conducted preliminary experiments and optimized processing parameters. For the first time, we added carbon fiber (CF) into HDPE to make CF-reinforced HDPE composites (CF-HDPE) using FDM and investigated the effects of CF on part quality, microstructure characteristics, and mechanical properties (including tensile properties and dynamic mechanical properties) of CF-reinforced HDPE composites. Experimental results show that the addition of CF was beneficial for not only improving the printability of FDM and quality of printed composite parts, but also for enhancing mechanical properties (such as Young’s Modulus and ultimate tensile strength) of the parts.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"137 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73768266","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}
Dingzhong Li, Hong Lu, Yongquan Zhang, Zidong Wu, He Huang, Meng Liu, Shaojun Wang
Automatic welding technology has been widely used in China’s industrial production. Welding robots with the characteristics of high efficiency and high qualification rate began to appear in the industrial production line. However, in order to protect their own competitiveness, most companies use closed source control mode for welding robots, resulting in high control cost, low system openness and poor flexibility. Therefore, it is of great significance to design an open-source and low-cost six degree of freedom welding robot motion control system based on STM32 microcontroller. According to the requirements of motion control system, the development board of dual core processor is selected as the core to complete the hardware design of motion control system. The software design of the control system adopts the framework of cooperative work between the upper computer and the lower computer, and the upper computer is developed with software, which has good human-computer interaction function; The lower computer is programmed through the modular idea, which is convenient for secondary development and has good expansibility. According to the standard DH method, the trajectory planning of the 6-DOF robot is realized, and the S-type acceleration and deceleration algorithm and other related algorithms are used to realize its more efficient and smooth motion control.
{"title":"Trajectory Control of 6-DOF Welding Robot Based on STM32","authors":"Dingzhong Li, Hong Lu, Yongquan Zhang, Zidong Wu, He Huang, Meng Liu, Shaojun Wang","doi":"10.1115/msec2022-85494","DOIUrl":"https://doi.org/10.1115/msec2022-85494","url":null,"abstract":"\u0000 Automatic welding technology has been widely used in China’s industrial production. Welding robots with the characteristics of high efficiency and high qualification rate began to appear in the industrial production line. However, in order to protect their own competitiveness, most companies use closed source control mode for welding robots, resulting in high control cost, low system openness and poor flexibility. Therefore, it is of great significance to design an open-source and low-cost six degree of freedom welding robot motion control system based on STM32 microcontroller. According to the requirements of motion control system, the development board of dual core processor is selected as the core to complete the hardware design of motion control system. The software design of the control system adopts the framework of cooperative work between the upper computer and the lower computer, and the upper computer is developed with software, which has good human-computer interaction function; The lower computer is programmed through the modular idea, which is convenient for secondary development and has good expansibility. According to the standard DH method, the trajectory planning of the 6-DOF robot is realized, and the S-type acceleration and deceleration algorithm and other related algorithms are used to realize its more efficient and smooth motion control.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"15 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90902316","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}
There has been an increasing interest for biodegradable polymers in recent years because they can be formed as scaffolds and safely removed from the body without the need for any surgical operation, and contribute to the healing process. However, the main problem in polymer-based biodegradable materials is the inability to obtain tunable biodegradation behavior to match healing, which limits the clinical feasibility of these biomaterials. In this study, it is aimed to model biodegradation behavior from short term experimental data in an effort to reduce time required for determination of bio-degradation parameters. Thus, the degradation behavior can be determined and controlled at a lower cost. In this context, the biodegradation behavior of poly-lactic acid (PLA) polymer which is widely used in biomedical applications, was investigated experimentally and numerically on different days related to fracture bone healing times (5–12 weeks). First, 4.5 mm × 4.5 mm × 4.5 mm cubes were printed using the fused deposition modelling (FDM). Then, printed samples were exposed to degradation in the incubator by immersion in phosphate buffered saline (PBS) solution at 37 °C at physiological conditions for different time periods (0, 15, 30, 61 and 90 days). Throughout degradation, water absorption, weight loss, mechanical properties and morphological changes were investigated. Water absorption increases up to 13% within 61 days and then decreases to 10% within 90 days. On the other hand, samples gain 1% weight for the first 15 days and following, start losing weight around 0.3% percent at the end of 90 days. This clearly indicates that degradation occurs and water replaces the degraded material. There are fluctuations in the stiffness values that decrease on the 15 and 61 days but they increase on the 30th and 90th days. The increases in stiffness can be attributed to the compressive resistance of the trapped water content. Microscopic investigation clearly verifies the water content that the colors of the samples (opacity increase) changed while no significant change in its size occurred at different degradation days. Experimental results indicate a degradation and mechanical behavior variation throughout the process while dimensional stability during the 90 day degradation period. Numerical model predicts the stiffness values reasonably well within 15 and 30 days of degradation, but differences for 61 and 90 days. This difference possibly stems from the fact that the numerical model does not include any water inclusion disturbance.
近年来，人们对生物可降解聚合物越来越感兴趣，因为它们可以作为支架形成，并且无需任何外科手术就可以安全地从体内移除，并且有助于愈合过程。然而，聚合物基生物可降解材料的主要问题是无法获得可调节的生物降解行为来匹配愈合，这限制了这些生物材料的临床可行性。在本研究中，旨在通过短期实验数据模拟生物降解行为，以减少确定生物降解参数所需的时间。因此，可以以较低的成本确定和控制降解行为。在此背景下，实验和数值研究了广泛应用于生物医学领域的聚乳酸(PLA)聚合物在与骨折愈合时间(5-12周)相关的不同天数的生物降解行为。首先，使用熔融沉积建模(FDM)打印4.5 mm × 4.5 mm × 4.5 mm的立方体。然后，在37°C的生理条件下，将打印的样品浸泡在磷酸盐缓冲盐水(PBS)溶液中，在培养箱中降解不同的时间(0、15、30、61和90天)。在整个降解过程中，研究了吸水率、失重率、力学性能和形态变化。吸水率在61天内上升至13%，90天内下降至10%。另一方面，样品在前15天体重增加1%，之后在90天结束时体重开始下降0.3%左右。这清楚地表明降解发生了，水取代了被降解的物质。刚度值的波动在第15和61天减小，但在第30和90天增大。刚度的增加可归因于截留含水量的抗压性。显微镜观察清楚地证实了在不同降解天数，样品的含水量发生了颜色(不透明度增加)的变化，而其大小没有明显变化。实验结果表明，在整个降解过程中存在降解和力学行为变化，而在90天的降解期内存在尺寸稳定性。数值模型较好地预测了退化15天和30天的刚度值，但61天和90天的刚度值存在差异。这种差异可能是由于数值模型没有考虑任何水包裹体干扰。
{"title":"Experimental and Numerical Investigation of Short-Term Bio-Degradation Behavior of 3D Printed PLA","authors":"R. Ilhan, Safa Şenaysoy, H. Lekesiz","doi":"10.1115/msec2022-80573","DOIUrl":"https://doi.org/10.1115/msec2022-80573","url":null,"abstract":"\u0000 There has been an increasing interest for biodegradable polymers in recent years because they can be formed as scaffolds and safely removed from the body without the need for any surgical operation, and contribute to the healing process. However, the main problem in polymer-based biodegradable materials is the inability to obtain tunable biodegradation behavior to match healing, which limits the clinical feasibility of these biomaterials. In this study, it is aimed to model biodegradation behavior from short term experimental data in an effort to reduce time required for determination of bio-degradation parameters. Thus, the degradation behavior can be determined and controlled at a lower cost. In this context, the biodegradation behavior of poly-lactic acid (PLA) polymer which is widely used in biomedical applications, was investigated experimentally and numerically on different days related to fracture bone healing times (5–12 weeks). First, 4.5 mm × 4.5 mm × 4.5 mm cubes were printed using the fused deposition modelling (FDM). Then, printed samples were exposed to degradation in the incubator by immersion in phosphate buffered saline (PBS) solution at 37 °C at physiological conditions for different time periods (0, 15, 30, 61 and 90 days). Throughout degradation, water absorption, weight loss, mechanical properties and morphological changes were investigated. Water absorption increases up to 13% within 61 days and then decreases to 10% within 90 days. On the other hand, samples gain 1% weight for the first 15 days and following, start losing weight around 0.3% percent at the end of 90 days. This clearly indicates that degradation occurs and water replaces the degraded material. There are fluctuations in the stiffness values that decrease on the 15 and 61 days but they increase on the 30th and 90th days. The increases in stiffness can be attributed to the compressive resistance of the trapped water content. Microscopic investigation clearly verifies the water content that the colors of the samples (opacity increase) changed while no significant change in its size occurred at different degradation days. Experimental results indicate a degradation and mechanical behavior variation throughout the process while dimensional stability during the 90 day degradation period. Numerical model predicts the stiffness values reasonably well within 15 and 30 days of degradation, but differences for 61 and 90 days. This difference possibly stems from the fact that the numerical model does not include any water inclusion disturbance.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"90 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82363964","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}
A. Sharifbaev, R. Mamidi, M. R. Gottimukkula, M. Gacura, G. Vanderlaan, X. Ji, D. Piovesan
Beyond an exceptional human toll, one of the most evident impacts of the ongoing COVID-19 pandemic is that of disrupted supply chain dynamics. Lessons learned here might help ameliorate the ability of frontline workers to secure personal protective equipment (PPE) such as N95 filtering facepiece respirators (FFRs) to prevent similar issues in future pandemics. A related concern is FFR waste streams, and the ability to recycle N95s using chemical or physical germicidal methods would greatly contribute to lessening PPE scarcity and providing relief to overall supply chains for all essential services. Early in 2020, the U.S. Food and Drug Administration (FDA) issued official guidance for sterilizers, disinfectant devices, and air purifiers with regards to the COVID-19 pandemic as a public health emergency bulletin. This guidance provided nonbinding recommendations for PPE and FFR decontamination processes, involving a wide spectrum of chemical and physical methods of sterilization. Many of the sterilization methods employ high heat or utilize polar chemical disinfectants that can compromise either the physical structure or the electrostatic properties of FFR fibers, thus attenuating the overall protection provided to the frontline worker. Ultraviolet germicidal irradiation (UVGI) has been employed for nearly a century to sterilize instruments and whole environments. UVGI offers numerous advantages as it is transitory by nature, leaving no chemical residue on the treated artifact. UVGI is also rapid, and depending on illumination sources, UVGI can easily scale to provide coverage to large areas. Here we provide an analysis of the regulatory aspect related to the use of UVC devices and describe our engineered design of a cost-efficient sterilization chamber that utilizes UVC for decontamination. Our design stresses a low-cost price point to facilitate easy manufacture for not only rapid deployment but also minimal impacts on supply chains. The device is intended to be easy to use, without any specialized training, and thus targets the general public for sanitizing non-washable materials, including PPE, FFR and other potential fomites, including electronic devices of daily use, that otherwise might harbor bacterial, viral and fungal pathogens.
{"title":"Manufacturing of the Eriedescent Sterilizing Device","authors":"A. Sharifbaev, R. Mamidi, M. R. Gottimukkula, M. Gacura, G. Vanderlaan, X. Ji, D. Piovesan","doi":"10.1115/msec2022-86032","DOIUrl":"https://doi.org/10.1115/msec2022-86032","url":null,"abstract":"\u0000 Beyond an exceptional human toll, one of the most evident impacts of the ongoing COVID-19 pandemic is that of disrupted supply chain dynamics. Lessons learned here might help ameliorate the ability of frontline workers to secure personal protective equipment (PPE) such as N95 filtering facepiece respirators (FFRs) to prevent similar issues in future pandemics. A related concern is FFR waste streams, and the ability to recycle N95s using chemical or physical germicidal methods would greatly contribute to lessening PPE scarcity and providing relief to overall supply chains for all essential services. Early in 2020, the U.S. Food and Drug Administration (FDA) issued official guidance for sterilizers, disinfectant devices, and air purifiers with regards to the COVID-19 pandemic as a public health emergency bulletin. This guidance provided nonbinding recommendations for PPE and FFR decontamination processes, involving a wide spectrum of chemical and physical methods of sterilization. Many of the sterilization methods employ high heat or utilize polar chemical disinfectants that can compromise either the physical structure or the electrostatic properties of FFR fibers, thus attenuating the overall protection provided to the frontline worker.\u0000 Ultraviolet germicidal irradiation (UVGI) has been employed for nearly a century to sterilize instruments and whole environments. UVGI offers numerous advantages as it is transitory by nature, leaving no chemical residue on the treated artifact. UVGI is also rapid, and depending on illumination sources, UVGI can easily scale to provide coverage to large areas.\u0000 Here we provide an analysis of the regulatory aspect related to the use of UVC devices and describe our engineered design of a cost-efficient sterilization chamber that utilizes UVC for decontamination. Our design stresses a low-cost price point to facilitate easy manufacture for not only rapid deployment but also minimal impacts on supply chains. The device is intended to be easy to use, without any specialized training, and thus targets the general public for sanitizing non-washable materials, including PPE, FFR and other potential fomites, including electronic devices of daily use, that otherwise might harbor bacterial, viral and fungal pathogens.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"455 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77043361","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}
Machining force and vibration signals are commonly used for process monitoring. While low-cost accelerometers are conveniently installed in machining setups, the direct measurement of machining forces in industrial applications is challenging. As an alternative to direct measurement, cutting forces can be estimated indirectly from vibration measurements, enabling the simultaneous monitoring of vibrations and forces from vibration signals only. In this paper, we two methods for estimating the dynamic milling forces from acceleration measurements during milling processes. The first method applies offline regularized deconvolution to the measured acceleration data to extract the forces causing them. The second method designs an online Augmented Kalman Filter to observe the forces as the augmented system states. The efficiency and performance of both methods are studied experimentally. The comparison between the indirectly estimated forces and the directly measured ones confirms the feasibility of using acceleration sensors to monitor the machining forces and the resulting vibrations simultaneously. Nevertheless, because the low-frequency contents of the forces are filtered in the resulting accelerations, only the dynamic component of the forces can be recovered. Experimental comparison of regularized deconvolution and augmented Kalman filter methods shows that the latter is more effective in recovering a larger portion of low-frequency content of the forces. Despite missing the low-frequency content, the reconstructed dynamic forces can still be used for process monitoring in applications where force sensors cannot be installed.
{"title":"Estimating Milling Forces From Vibration Measurements","authors":"M. Joddar, K. Ahmadi","doi":"10.1115/msec2022-85157","DOIUrl":"https://doi.org/10.1115/msec2022-85157","url":null,"abstract":"\u0000 Machining force and vibration signals are commonly used for process monitoring. While low-cost accelerometers are conveniently installed in machining setups, the direct measurement of machining forces in industrial applications is challenging. As an alternative to direct measurement, cutting forces can be estimated indirectly from vibration measurements, enabling the simultaneous monitoring of vibrations and forces from vibration signals only. In this paper, we two methods for estimating the dynamic milling forces from acceleration measurements during milling processes. The first method applies offline regularized deconvolution to the measured acceleration data to extract the forces causing them. The second method designs an online Augmented Kalman Filter to observe the forces as the augmented system states. The efficiency and performance of both methods are studied experimentally. The comparison between the indirectly estimated forces and the directly measured ones confirms the feasibility of using acceleration sensors to monitor the machining forces and the resulting vibrations simultaneously. Nevertheless, because the low-frequency contents of the forces are filtered in the resulting accelerations, only the dynamic component of the forces can be recovered. Experimental comparison of regularized deconvolution and augmented Kalman filter methods shows that the latter is more effective in recovering a larger portion of low-frequency content of the forces. Despite missing the low-frequency content, the reconstructed dynamic forces can still be used for process monitoring in applications where force sensors cannot be installed.","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":"76258584","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}
Nanoparticle-included polymeric composite coatings with preferential nanoparticle alignment and oriented structures show improved functional and structural properties than randomly oriented structures, suitable for broad applications in microelectronics, automobile, defense, and space missions. Traditionally used techniques, such as drop-casting, chemically modified surfaces, and external fields, have been used for self-assembly but with several disadvantages, such as material limitations. Thus, there is a need to develop a new approach for generating hierarchical nanoparticle structures. Our unique processing is based on advanced additive manufacturing with a colloidal suspension-based deposition approach for layer-by-layer deposition of anisotropic nanoparticles. Leveraging the colloidal deposition technique, these anisotropic nanoparticles were deposited onto the 3D printed substrates with designed patterning. The presence of micropatterns generates selective nanoparticle distribution and assembly along with hydrodynamic forces to initiate the region-specific microscale patterning and nanoscale alignment of 1D and 2D nanoparticles. The polymer and nanoparticle composite film showed different deposition morphologies (e.g., straight or wavy films). In addition, the influence of nanoparticle deposition morphology on functional properties was investigated. This novel technique shows the potential to scale up microelectronics production by 3D printing electronic structures, including interdigitated devices, supercapacitors, fuel cells, and circuits.
{"title":"1D and 2D Nanoparticle Assembly Compliant With Tuned 3D-Printed Topology","authors":"Sayli Jambhulkar, Kenan Song","doi":"10.1115/msec2022-85050","DOIUrl":"https://doi.org/10.1115/msec2022-85050","url":null,"abstract":"\u0000 Nanoparticle-included polymeric composite coatings with preferential nanoparticle alignment and oriented structures show improved functional and structural properties than randomly oriented structures, suitable for broad applications in microelectronics, automobile, defense, and space missions. Traditionally used techniques, such as drop-casting, chemically modified surfaces, and external fields, have been used for self-assembly but with several disadvantages, such as material limitations. Thus, there is a need to develop a new approach for generating hierarchical nanoparticle structures. Our unique processing is based on advanced additive manufacturing with a colloidal suspension-based deposition approach for layer-by-layer deposition of anisotropic nanoparticles. Leveraging the colloidal deposition technique, these anisotropic nanoparticles were deposited onto the 3D printed substrates with designed patterning. The presence of micropatterns generates selective nanoparticle distribution and assembly along with hydrodynamic forces to initiate the region-specific microscale patterning and nanoscale alignment of 1D and 2D nanoparticles. The polymer and nanoparticle composite film showed different deposition morphologies (e.g., straight or wavy films). In addition, the influence of nanoparticle deposition morphology on functional properties was investigated. This novel technique shows the potential to scale up microelectronics production by 3D printing electronic structures, including interdigitated devices, supercapacitors, fuel cells, and circuits.","PeriodicalId":45459,"journal":{"name":"Journal of Micro and Nano-Manufacturing","volume":"55 3 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88473332","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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