Direct-write additive manufacturing refers to a rich and growing repertoire of well-established fabrication techniques that builds solid objects directly from compu- ter-generated solid models without elaborate interm...Direct-write additive manufacturing refers to a rich and growing repertoire of well-established fabrication techniques that builds solid objects directly from compu- ter-generated solid models without elaborate intermediate fabrication steps. At the macroscale, direct-write techni- ques such as stereolithography, selective laser sintering, fused deposition modeling ink-jet printing, and laminated object manufacturing have significantly reduced concept- to-product lead time, enabled complex geometries, and importantly, has led to the renaissance in fabrication known as the maker movement. The technological premises of all direct-write additive manufacturing are identical--converting computer generated three-dimen- sional models into layers of two-dimensional planes or slices, which are then reconstructed sequentially into three- dimensional solid objects in key differences between the a layer-by-layer format. The various additive manufactur- ing techniques are the means of creating the finished layers and the ancillary processes that accompany them. While still at its infancy, direct-write additive manufacturing techniques at the microscale have the potential to significantly lower the barrier-of-entry--in terms of cost, time and training--for the prototyping and fabrication of MEMS parts that have larger dimensions, high aspect ratios, and complex shapes. In recent years, significant advancements in materials chemistry, laser technology, heat and fluid modeling, and control systems have enabled additive manufacturing to achieve higher resolutions at the micrometer and nanometer length scales to be a viable technology for MEMS fabrication. Compared to traditional MEMS processes that rely heavily on expensive equip- ment and time-consuming steps, direct-write additive manufacturing techniques allow for rapid design-to- prototype realization by limiting or circumventing the need for cleanrooms, photolithography and extensive training. With current direct-write additive manufacturingtechnologies, it is possible to fabricate unsophisticated micrometer scale structures at adequate resolutions and precisions using materials that range from polymers, metals, ceramics, to composites. In both academia and industry, direct-write additive manufacturing offers extra- ordinary promises to revolutionize research and develop- ment in microfabrication and MEMS technologies. Importantly, direct-write additive manufacturing could appreciably augment current MEMS fabrication technologies, enable faster design-to-product cycle, empower new paradigms in MEMS designs, and critically, encourage wider participation in MEMS research at institutions or for individuals with limited or no access to cleanroom facilities. This article aims to provide a limited review of the current landscape of direct-write additive manufacturing techniques that are potentially applicable for MEMS microfabrication.展开更多
We present a direct-write patterning method for the realization of electroluminescent(EL)line art using a surface-emissive light-emitting electrochemical cell with its electrolyte and EL material separated into a bila...We present a direct-write patterning method for the realization of electroluminescent(EL)line art using a surface-emissive light-emitting electrochemical cell with its electrolyte and EL material separated into a bilayer structure.The line-art emission is achieved through subtractive patterning of the electrolyte layer with a stylus,and the single-step patterning can be either manual for personalization and uniqueness or automated for high throughput and repeatability.We demonstrate that the light emission is effectuated by cation-assisted electron injection in the patterned regions and that the resulting emissive lines can be as narrow as a few micrometers.The versatility of the method is demonstrated through the attainment of a wide range of light-emission patterns and colors using a variety of different materials.Wepropose that this low-voltage-driven and easy-to-modify luminescent line-art technology could be of interest for emerging applications,such as active packaging and personalized gadgets.展开更多
A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynami...A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynamic direct-writing （EDW） is utilized to print the conductor-insulator--conductor multi-layer ~nterconne^ction structure. Silver ink is chosen to print the conductor pattern, and a polyvinylpyrrolidone （PVP） solution is util^zed to f^bricate the insulator layer between the bottom and top conductor patterns. The influences of EDW process parameters on the line width of the printed conductor and insulator patterns are studied systematically. The obtained ~es^l~s show that the line width of the printed structure increases with the increase of the flow rate, but decreases with the increase of applied voltage and PVP content in the solution. The average resistivity values of the bottom and top silver conductor tracks are determined to be 1.34 × 10-7 Ω.m and 1.39×10-7 Ω.m, respectively. The printed PVP layer between the two conductor tracks is well insulated, which can meet the insulation requirement of the electronic devices. This study offers an alternative, fast, and cost-effective method of fabricating conductor-insulator-conductor multi-layer interconnections in the electronic industry.展开更多
Three groups of three-dimensional （3D） TiO2 woodpile electromagnetic gap materials with tailed rheological properties were developed for direct-written fabrication. Appropriate amount of polyethyleneimine （PEI） di...Three groups of three-dimensional （3D） TiO2 woodpile electromagnetic gap materials with tailed rheological properties were developed for direct-written fabrication. Appropriate amount of polyethyleneimine （PEI） dispersants allow the preparation of TiO2 inks with a high solid content of 42 vol.%, which enables them to flow through the nozzles easily. The inks exhibit pseudoplastic behavior. The measured microwave characteristics of the results agree well with simulations based on plane wave expansion （PWE）.展开更多
Specially shaped permanent magnet structures can satisfy the requirements of equipment with limited space or unique shapes.Thereby,these optimize the distribution of magnetic fields.However,traditional manufacturing m...Specially shaped permanent magnet structures can satisfy the requirements of equipment with limited space or unique shapes.Thereby,these optimize the distribution of magnetic fields.However,traditional manufacturing methods are limited by the mold design and insufficient material utilization.In this study,a polymer-based Nd_(2)Fe_(14)B(NdFeB)magnetic slurry was developed based on direct ink writing(DIW)3D printing technology.A rapidly volatilizable magnetic slurry was used to achieve 3D oriented controllable layering,thus realizing the direct molding fabrication of NdFeB permanent magnets with complex structures.By exploring and optimizing the 3D printing process parameters,specially shaped bonded NdFeB permanent magnet structures with high precision and shape fidelity were prepared.The test results indicated that the remnant magnetization of the printed magnets was proportional to the NdFeB content in the slurry,the coercivity closely matched that of the original powder,and the mechanical properties of the printed magnets were favorable.Building on this,a magnetically driven helical-structure robot was designed and printed to achieve stable motion in low-Reynolds-number fluids.This paper presents a new,low-cost solution for the room-temperature preparation of shape-bonded NdFeB permanent magnets.展开更多
文摘Direct-write additive manufacturing refers to a rich and growing repertoire of well-established fabrication techniques that builds solid objects directly from compu- ter-generated solid models without elaborate intermediate fabrication steps. At the macroscale, direct-write techni- ques such as stereolithography, selective laser sintering, fused deposition modeling ink-jet printing, and laminated object manufacturing have significantly reduced concept- to-product lead time, enabled complex geometries, and importantly, has led to the renaissance in fabrication known as the maker movement. The technological premises of all direct-write additive manufacturing are identical--converting computer generated three-dimen- sional models into layers of two-dimensional planes or slices, which are then reconstructed sequentially into three- dimensional solid objects in key differences between the a layer-by-layer format. The various additive manufactur- ing techniques are the means of creating the finished layers and the ancillary processes that accompany them. While still at its infancy, direct-write additive manufacturing techniques at the microscale have the potential to significantly lower the barrier-of-entry--in terms of cost, time and training--for the prototyping and fabrication of MEMS parts that have larger dimensions, high aspect ratios, and complex shapes. In recent years, significant advancements in materials chemistry, laser technology, heat and fluid modeling, and control systems have enabled additive manufacturing to achieve higher resolutions at the micrometer and nanometer length scales to be a viable technology for MEMS fabrication. Compared to traditional MEMS processes that rely heavily on expensive equip- ment and time-consuming steps, direct-write additive manufacturing techniques allow for rapid design-to- prototype realization by limiting or circumventing the need for cleanrooms, photolithography and extensive training. With current direct-write additive manufacturingtechnologies, it is possible to fabricate unsophisticated micrometer scale structures at adequate resolutions and precisions using materials that range from polymers, metals, ceramics, to composites. In both academia and industry, direct-write additive manufacturing offers extra- ordinary promises to revolutionize research and develop- ment in microfabrication and MEMS technologies. Importantly, direct-write additive manufacturing could appreciably augment current MEMS fabrication technologies, enable faster design-to-product cycle, empower new paradigms in MEMS designs, and critically, encourage wider participation in MEMS research at institutions or for individuals with limited or no access to cleanroom facilities. This article aims to provide a limited review of the current landscape of direct-write additive manufacturing techniques that are potentially applicable for MEMS microfabrication.
基金support from the Swedish Foundation for Strategic Researchthe Swedish Research Council+3 种基金the Swedish Energy Agencythe Kempe Foundationthe Knut and Alice Wallenberg FoundationsAforsk.
文摘We present a direct-write patterning method for the realization of electroluminescent(EL)line art using a surface-emissive light-emitting electrochemical cell with its electrolyte and EL material separated into a bilayer structure.The line-art emission is achieved through subtractive patterning of the electrolyte layer with a stylus,and the single-step patterning can be either manual for personalization and uniqueness or automated for high throughput and repeatability.We demonstrate that the light emission is effectuated by cation-assisted electron injection in the patterned regions and that the resulting emissive lines can be as narrow as a few micrometers.The versatility of the method is demonstrated through the attainment of a wide range of light-emission patterns and colors using a variety of different materials.Wepropose that this low-voltage-driven and easy-to-modify luminescent line-art technology could be of interest for emerging applications,such as active packaging and personalized gadgets.
基金supported by the Key Program of the National Natural Science Foundation of China(Grant No.51035002)the National Natural Science Foundation of China(Grant No.51305373)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120121120035)
文摘A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynamic direct-writing （EDW） is utilized to print the conductor-insulator--conductor multi-layer ~nterconne^ction structure. Silver ink is chosen to print the conductor pattern, and a polyvinylpyrrolidone （PVP） solution is util^zed to f^bricate the insulator layer between the bottom and top conductor patterns. The influences of EDW process parameters on the line width of the printed conductor and insulator patterns are studied systematically. The obtained ~es^l~s show that the line width of the printed structure increases with the increase of the flow rate, but decreases with the increase of applied voltage and PVP content in the solution. The average resistivity values of the bottom and top silver conductor tracks are determined to be 1.34 × 10-7 Ω.m and 1.39×10-7 Ω.m, respectively. The printed PVP layer between the two conductor tracks is well insulated, which can meet the insulation requirement of the electronic devices. This study offers an alternative, fast, and cost-effective method of fabricating conductor-insulator-conductor multi-layer interconnections in the electronic industry.
文摘Three groups of three-dimensional （3D） TiO2 woodpile electromagnetic gap materials with tailed rheological properties were developed for direct-written fabrication. Appropriate amount of polyethyleneimine （PEI） dispersants allow the preparation of TiO2 inks with a high solid content of 42 vol.%, which enables them to flow through the nozzles easily. The inks exhibit pseudoplastic behavior. The measured microwave characteristics of the results agree well with simulations based on plane wave expansion （PWE）.
基金supported by National Natural Science Foundation of China(Grant Nos.52375348,52175331)National Natural Science Foundation of Shandong Province(Grant Nos.ZR2022ME014,ZR2020ZD04).
文摘Specially shaped permanent magnet structures can satisfy the requirements of equipment with limited space or unique shapes.Thereby,these optimize the distribution of magnetic fields.However,traditional manufacturing methods are limited by the mold design and insufficient material utilization.In this study,a polymer-based Nd_(2)Fe_(14)B(NdFeB)magnetic slurry was developed based on direct ink writing(DIW)3D printing technology.A rapidly volatilizable magnetic slurry was used to achieve 3D oriented controllable layering,thus realizing the direct molding fabrication of NdFeB permanent magnets with complex structures.By exploring and optimizing the 3D printing process parameters,specially shaped bonded NdFeB permanent magnet structures with high precision and shape fidelity were prepared.The test results indicated that the remnant magnetization of the printed magnets was proportional to the NdFeB content in the slurry,the coercivity closely matched that of the original powder,and the mechanical properties of the printed magnets were favorable.Building on this,a magnetically driven helical-structure robot was designed and printed to achieve stable motion in low-Reynolds-number fluids.This paper presents a new,low-cost solution for the room-temperature preparation of shape-bonded NdFeB permanent magnets.
