KAPIV教育教学理念运用于“3D打印”课程的初步探索

针对“3D打印”课程内容冗杂、教学方法单一、缺少特色等教学困境,文章围绕KAPIV教育教学理念,深入探讨知识、能力、实践、创新及品德要素的内涵,梳理出在教学过程中学生需要掌握的知识点、拟达成的能力、实践教学流程、创新路径及学生所应具备的良好品德,并以东方红3号科考船为例进行实践探索。经检验,课程教学初见成效。

燃煤“3D打印”式堆叠分层掺配流程

智慧燃料是燃煤电厂数字化管理、降本增效的必然发展趋势,该目标的实现主要依托软件系统完成燃煤掺配方案的制定和设备运行参数的计算,通过硬件设备执行控制系统指令,其硬件执行方式对燃煤掺配的均匀性具有重要作用。现针对斗轮机于煤场的自动化掺配工艺,通过对“3D打印”技术进行分析,完成斗轮堆取料机对不同特性燃煤的分层平铺、逐层叠加掺配方式的研究,解决燃煤掺配精确性、均匀性的问题,为燃煤掺烧的智能化、全自动运行提供设备运行基础。

音色造型的“3D打印”

音色造型的"3D打印"是对故事人物"对话"的多维造型,使之得到立体化的口语呈现,包含质感定位、色彩配置、光感协同三个要素。质感定位是对人物个性特征的总体定位,形成脚本;色彩配置是根据质感定位,实施声音色彩造型;光感协同则是用具有直观视觉作用的动作与表情,对声音色彩进行协同。在设计与实施的过程中,都应讲究音色造型的逻辑。

基于“三生融合”理念的产业小镇城市设计——以西安市3D打印特色小镇为例

小城镇作为城乡空间重要的融合点,具有城乡联动发展、引领产业升级转型、促进创新创业等积极效益,"三生融合"理念体现现代化发展的必然趋势。为此,文章从产业、空间、人文、特色四个维度对规划实践路径加以重构,通过建设特色小镇来实现生产要素创新集聚和功能布局优化,并以西安3D打印特色小镇为例,探讨"三生融合"理念下的规划要求和设计对策,以期为产业小城镇的发展提供借鉴。

创客教育下的“3D设计与打印”课程应用实践

要将"3D设计与打印"课程实践引入创客教育理念,可以以学习金字塔理论为指导,翻转课堂为中心教学方式,通过任务驱动、进行小组讨论来完成数字化模型和实物输出,并进行分享交流,引导学生综合运用多学科知识解决问题,能够不断提升学生综合竞争力。

关于科学技术创新的辩证分析——以“3D”打印技术为例

"3D"打印技术的创新,一方面促进了生产力的发展,尤其是带动了世界范围内制造业的转型升级;另一方面,"3D"打印技术所带来的伦理道德冲击与知识产权的问题,让人们对这项新技术产生了不同的看法与理解。本文从科学技术创新的角度,以辩证分析为研究方法,全面讨论了"3D"打印技术的优势及存在的问题。

基于3D打印技术的技师研修微项目研修路径研究

随着3D打印技术的日渐成熟,3D打印技术走进越来越多的校园,走向越来越多课堂。在数技师研修中加入3D打印技术,不仅可以让技师研修项目的模型完整的呈现在学生面前,让学生发现不足,更好的改进;并且能够充分调动了技师研修学生学习的积极性。“3D打印技术”微项目通过3D打印技术先出来的模型,来检查方案的可行性,不仅避免了因项目设计不合理出现失败的现象,而且省掉了很多复杂的理论验证流程,提升了数控技师研修的效率和质量。

Composite bioabsorbable vascular stents via 3D bio-printing and electrospinning for treating stenotic vessels

A new type of vascular stent is designed for treating stenotic vessels. Aiming at overcoming the shortcomings of existing equipment and technology for preparing a bioabsorbable vascular stent （BVS）, a new method which combines 3D bio-printing and electrospinning to prepare the composite bioabsorbable vascular stent （CBVS） is proposed. The inner layer of the CBVS can be obtained through 3D bio- printing using poly-p-dioxanone （PPDO）. The thin nanofiber film that serves as the outer layer can be built through electrospinning using mixtures of chitosan-PVA （poly （vinyl alcohol））. Tests of mechanical properties show that the stent prepared through 3D bio-printing combined with electrospinning is better than that prepared through 3D bio- printing alone. Cells cultivated on the CBVS adhere and proliferate better due to the natural, biological chitosan in the outer layer. The proposed complex process and method can provide a good basis for preparing a controllable drug-carrying vascular stent. Overall, the CBVS can be a good candidate for treating stenotic vessels.

Visual representation and characterization of three-dimensional hydrofracturing cracks within heterogeneous rock through 3D printing and transparent models

The heterogeneity of unconventional reservoir rock tremendously affects its hydrofracturing behavior. A visual representation and accurate characterization of the three-dimensional （3D） growth and distribution of hydrofracturing cracks within heterogeneous rocks is of particular use to the design and implementation of hydrofracturing stimulation of unconventional reservoirs. However, because of the difficulties involved in visually representing and quantitatively characterizing a 3D hydrofracturing crack-network, this issue remains a challenge. In this paper, a novel method is proposed for physically visualizing and quantitatively characterizing the 3D hydrofracturing crack-network distributed through a heterogeneous structure based on a natural glutenite sample. This method incorporates X-ray microfocus computed tomography （μCT）, 3D printing models and hydrofracturing triaxial tests to represent visually the heterogeneous structure, and the 3D crack growth and distribution within a transparent rock model during hydrofracturing. The coupled effects of material heterogeneity and confining geostress on the 3D crack initiation and propagation were analyzed. The results indicate that the breakdown pressure of a heterogeneous rock model is significantly affected by material heterogeneity and confining geostress. The measured breakdown pressures of heterogeneous models are apparently different from those predicted by traditional theories. This study helps to elucidate the quantitative visualization and characterization of the mechanism and influencing factors that determine the hydrofracturing crack initiation and propagation in heterogeneous reservoir rocks.

A Review on the 3D Printing of Functional Structures for Medical Phantoms and Regenerated Tissue and Organ Applications

Medical models, or ＂phantoms,＂ have been widely used for medical training and for doctor-patient interactions. They are increasingly used for surgical planning, medical computational models, algorithm verification and validation, and medical devices development. Such new applications demand high-fidelity, patient-specific, tissue-mimicking medical phantoms that can not only closely emulate the geometric structures of human organs, but also possess the properties and functions of the organ structure. With the rapid advancement of three-dimensional （3D） printing and 3D bioprinting technologies, many researchers have explored the use of these additive manufacturing techniques to fabricate functional medical phantoms for various applications. This paper reviews the applications of these 3D printing and 3D bioprinting technologies for the fabrication of functional medical phantoms and bio-structures. This review specifically discusses the state of the art along with new developments and trends in 3D printed functional medical phantoms （i.e., tissue-mimicking medical phantoms, radiologically relevant medical phantoms, and physiological medical phantoms） and 3D bio-printed structures （i.e., hybrid scaffolding materials, convertible scaffolds, and integrated sensors） for regenerated tissues and organs.

High pressure EIGA preparation and 3D printing capability of Ti-6Al-4V powder

Ti-6 Al-4 V alloy powder was processed by electrode induction melting gas atomization(EIGA)at high gas pressure(5.5-7.0 MPa).The effects of atomizing gas pressure on the powder characteristics and the microstructure,along with the mechanical properties of the as-fabricated block by laser melting deposition(LMD),were investigated.The results indicate that the diameters of powders are distributed in a wide range of sizes from 1 to 400μm,and the median powder size(d50)decreases with increasing gas pressure.The powders with a size fraction of 100-150μm obtained at gas pressures of 6.0 and 6.5 MPa have better flowability.The oxygen content is consistent with the change trend of gas pressure within a low range of 0.06%-0.20%.Specimens fabricated by LMD are mainly composed ofα+βgrains with a fine lamellar Widmanstatten structures and have the ultimate tensile strength(UTS)and yield strength of approximately 1100 and 1000 MPa,respectively.Furthermore,the atomized powders have a favorable 3 D printing capability,and the mechanical properties of Ti-6 Al-4 V alloys manufactured by LMD typically exceed those of their cast or wrought counterparts.

Indirect 3D printed ceramic:A literature review

Additive manufacturing(AM),also known as 3D-printing(3DP)technology,is an advanced manufacturing technology that has developed rapidly in the past 40 years.However,the ceramic material printing is still challenging because of the issue of cracking.Indirect 3D printing has been designed and drawn attention because of its high manufacturing speed and low cost.Indirect 3D printing separates the one-step forming process of direct 3D printing into binding and material sintering,avoiding the internal stress caused by rapid cooling,making it possible to realize the highquality ceramic component with complex shape.This paper presents the research progress of leading indirect 3D printing technologies,including binder jetting(BJ),stereolithography(SLA),and fused deposition modeling(FDM).At present,the additive manufacturing of ceramic materials is mainly achieved through indirect 3D printing technology,and these materials include silicon nitride,hydroxyapatite functional ceramics,silicon carbide structural ceramics.

Femtosecond-laser direct writing 3D micro/nano-lithography using VIS-light oscillator

Here we report a femtosecond laser direct writing(a precise 3D printing also known as two-photon polymerization lithography) of hybrid organic-inorganic SZ2080^(TM)pre-polymer without using any photo-initiator and applying ~100 fs oscillator operating at 517 nm wavelength and 76 MHz repetition rate. The proof of concept was experimentally demonstrated and benchmarking 3D woodpile nanostructures, micro-scaffolds, free-form micro-object “Benchy” and bulk micro-cubes are successfully produced. The essential novelty underlies the fact that non-amplified laser systems delivering just 40-500 p J individual pulses are sufficient for inducing localized cross-linking reactions within hundreds of nanometers in cross sections. And it is opposed to the prejudice that higher pulse energies and lower repetition rates of amplified lasers are necessary for structuring non-photosensitized polymers. The experimental work is of high importance for fundamental understanding of laser enabled nanoscale 3D additive manufacturing and widens technology’ s field of applications where the avoidance of photo-initiator is preferable or is even a necessity, such as micro-optics, nano-photonics, and biomedicine.

Sintering properties of in situ Ti-TiB microlattices created by 3D extrusion printing of TiH_(2)+TiB_(2) inks

A direct 3D extrusion printing technique was used to produce Ti-TiB filaments and microlattices.The sintering properties of 3D ink extrusion and sintering of in situ Ti-TiB composite structures made from TiH_(2)+TiB_(2) ink were investigated.The sintering kinetics of TiH2+TiB2 inks was studied during densification by pressureless sintering at 1050−1200℃ for 4−24 h in Ar.The linear shrinkage,grain size,microhardness,X-ray diffraction(XRD)patterns,and microstructural evolution of the Ti-TiB composite were studied.The sintering temperature had a more pronounced influence than the sintering time on the density of the Ti-TiB composite.There were two kinds of pores,irregular and spherical,caused by the Kirkendall effect and indiffusable gases.The TiB formed by in situ synthesis existed as either separated TiB whiskers(needle-like shapes)or clusters of TiB whiskers.The results of this work could be useful for controlling microporosity through incomplete sintering within filaments,especially for the production of in situ Ti-TiB with high volume fractions of TiB or other composites.

3D gel printing of VC reinforced high vanadium high-speed steel

Due to their high hardness and high strength,VC reinforced hard materials such as high vanadium high-speed steel(HVHSS)are not suitable for machining to obtain complex shape with low cost.Therefore,3D gel printing(3DGP)was employed to print HVHSS parts,using highly loaded slurry with 60%solid content as printing slurry.After printing parameters optimization,the printing sample had good surface quality,and obvious printing lines were observed.The extruded filament was in-situ cured,thus enough to maintain the designed shape.Uniform sintering shrinkage with a shrinkage rate of about 15%was obtained in the as-sintered sample with relative density of 99%.The surface roughness decreased from 6.5μm to 3.8μm.Fine carbides(<1μm)and dense microstructure were achieved.Besides,the as-sintered sample had comprehensive performance of HRC60 in hardness,3000 MPa in bend strength,and 20−26 J in impact energy.This study proposed one promising method to directly manufacture complex-shaped hard materials without subsequent machining.

Liu Zhongjun:3D Printing Reshapes Orthopedic Surgery

THERE is a 3D printing lab in the First Ward Zone of the Department of Orthopedics at Peking University Third Hospital（PUTH）.Although not big,it’s where Professor Liu Zhongjun,director of the department,spends most of his time,when not dealing with patients and students.

Effect of fractures on mechanical behavior of sand powder 3D printing rock analogue under triaxial compression

In practical engineering applications,rock mass are often found to be subjected to a triaxial stress state.Concurrently,defects like joints and fractures have a notable impact on the mechanical behavior of rock mass.Such defects are identified as crucial contributors to the failure and instability of the surrounding rock,subsequently impacting the engineering stability.The study aimed to investigate the impact of fracture geometry and confining pressure on the deformation,failure characteristics,and strength of specimens using sand powder 3D printing technology and conventional triaxial compression tests.The results indicate that the number of fractures present considerably influences the peak strength,axial peak strain and elastic modulus of the specimens.Confining pressure is an important factor affecting the failure pattern of the specimen,under which the specimen is more prone to shear failure,but the initiation,expansion and penetration processes of secondary cracks in different fracture specimens are different.This study confirmed the feasibility of using sand powder 3D printing specimens as soft rock analogs for triaxial compression research.The insights from this research are deemed essential for a deeper understanding of the mechanical behavior of fractured surrounding rocks when under triaxial stress state.

Integrated 3D bioprinting-based geometry-control strategy for fabricating corneal substitutes

Background:The shortage of donor corneas is a severe global issue,and hence the development of corneal alternatives is imperative and urgent.Although attempts to produce artificial cornea substitutes by tissue engineering have made some positive progress,many problems remain that hamper their clinical application worldwide.For example,the curvature of tissue-engineered cornea substitutes cannot be designed to fit the bulbus oculi of patients.Objective:To overcome these limitations,in this paper,we present a novel integrated three-dimensional(3 D) bioprintingbased cornea substitute fabrication strategy to realize design,customized fabrication,and evaluation of multi-layer hollow structures with complicated surfaces.Methods:The key rationale for this method is to combine digital light processing(DLP) and extrusion bioprinting into an integrated 3 D cornea bioprinting system.A designable and personalized corneal substitute was designed based on mathematical modelling and a computer tomography scan of a natural cornea.The printed corneal substitute was evaluated based on biomechanical analysis,weight,structural integrity,and fit.Results:The results revealed that the fabrication of high water content and highly transparent curved films with geometric features designed according to the natural human cornea can be achieved using a rapid,simple,and low-cost manufacturing process with a high repetition rate and quality.Conclusions:This study demonstrated the feasibility of customized design,analysis,and fabrication of a corneal substitute.The programmability of this method opens up the possibility of producing substitutes for other cornea-like shell structures with different scale and geometry features,such as the glomerulus,atrium,and oophoron.

Coaxial 3D bioprinting of organ prototyps from nutrients delivery to vascularization

Vascular networks inside organs provide the means for metabolic exchange and adequate nutrition.Similarly,vascular or nutrient networks are needed when building tissue constructs>500μm in vitro due to the hydrogel compact pore size of bioinks.As the hydrogel used in bioinks is rather soft,it is a great challenge to reconstruct effective vascular networks.Recently,coaxial 3 D bioprinting was developed to print tissue constructs directly using hollow hydrogel fibers,which can be treated as built-in microchannels for nutrient delivery.Furthermore,vascular networks could be printed directly through coaxial 3 D bioprinting.This review summarizes recent advances in coaxial bioprinting for the fabrication of complex vascularized tissue constructs including methods,the effectiveness of varying strategies,and the use of sacrificial bioink.The limitations and challenges of coaxial 3 D bioprinting are also summarized.

Self-healing materials enable free-standing seamless large-scale 3D printing

Three-dimensional(3 D)printing has had a large impact on various fields,with fused deposition modeling(FDM)being the most versatile and cost-effective 3 D printing technology.However,FDM often requires sacrificial support structures,which significantly complicates the processing and increases the cost.Furthermore,poor layer-to-layer adhesion greatly affects the mechanical stability of 3D-printed objects.Here,we present a new Print-Healing strategy to address the aforementioned challenges.A polymer ink(Cu-DOU-CPU)with synergetic triple dynamic bonds was developed to have excellent printability and room-temperature self-healing ability.Objects with various shapes were printed using a simple compact 3D printer,and readily assembled into large sophisticated architectures via self-healing.Triple dynamic bonds induce strong binding between layers.Additionally,damaged printed objects can spontaneously heal,which significantly elongates their service life.This work paves a simple and powerful way to solve the key bottlenecks in FDM 3D printing,and will have diverse applications.