Compatible hybrid 3D printing of metal and nonmetal inks for direct manufacture of end functional devices

The currently available 3D printing still cannot simultaneously deal with the metal and nonmetal inks together due to their huge difference in the melting points and poor compatible printability between each other. Here through introducing the low melting point alloy Bi₃₅In_48.6Sn₁₆Zn_0.4 and silicone rubber as functional inks, we proposed a compatible hybrid 3D printing method for manufacturing the desired device, the supporting substrate and the allied package structure together. The principle of pneumatic-typed 3D printing of multiple inks was described and typical physical properties of the ink Bi₃₅In_48.6Sn₁₆Zn_0.4 were measured. Several key factors dominating the printing quality such as the temperature of the printing head, the air pressure exerted upon the liquid metal ink in the syringe, the moving velocity and the height of the printing head etc. were clarified. A general way of directly printing out 3D structured electronic devices consisting of both metal and nonmetal materials was demonstrated. Such hybrid objects were patterned and formed up layer by layer with Bi₃₅In_48.6Sn₁₆Zn_0.4 alloy and silicone rubber which would become solidified after standing for a period of time under room temperature. To illustrate the compatible printability of these printing inks, a three-layer tricolor LED stereo circuit with controlled lighting capability was further manufactured and evaluated. The present study opens an important hybrid 3D printing way for directly manufacturing functional and structural end devices in an easy and low cost way.     

Spraying printing of liquid metal electronics on various clothes to compose wearable functional device

Liquid metal printing is emerging as an important tool for making wearable electronics. However, very limited academic efforts were made to fulfill such an increasing need. This paper is dedicated to present relatively complete theoretical and experimental characterizations for liquid metal spraying printing towards developing wearable electronic textile. The practical conditions of liquid metal droplets in the spraying printing process such as the jet velocity, the size distribution of droplets and their evenness degree, the morphology of droplets and their unrolling areas after impacting the substrate are quantified. The dominating factors, including the oxidation of liquid metal and the pressure force on cloth substrate during the impacting process, which ensure liquid metal firmly adhere to the cloth, are clarified. Further, various clothes are comparatively investigated to test their capabilities in printing liquid metal conductors, where the resistance difference can be over thousand-fold. In addition to interpreting the basic mechanisms and performances of the spraying printing, two programmable flexible circuits with specifically designed functions such as blinking LED lighting and wireless infrared temperature measurement via current manufacture technology were also demonstrated and evaluated for their washable ability. With the realization of wearable modules via liquid metal printing technology, it can be expected that flexible functional devices on cloth fabricated quickly and directly would witness more broad applications in the coming time.     

导电油墨在印刷电子方面的研究进展

随着新型柔性电子器件的出现、发展与应用,印刷电子的制备工艺相对于其他传统技术表现出成本低、效率高以及可大面积生产等比较优势,逐步受到广泛关注.而导电油墨作为印刷电子工艺中的重要组成部分,越来越多的科研工作者对其进行了研究.为此针对导电油墨进行了相关论述,并阐明了未来导电油墨的发展方向,其中重点介绍了金属纳米颗粒型、金属有机分解型和金属纳米线型等不同导电体系的导电油墨,评述了它们的整体特点、制作方法和应用实例,并针对各油墨体系提出了改进其在基材上的附着力设计方法.可以看出:在印刷电子工艺中所使用的导电油墨,其性质与特征决定了整个制备工艺的流程和最终产品性能,并且将会继续沿着低成本、环境友好型和高导电性等方向进行发展.     

Colorful liquid metal printed electronics

Liquid metal based printed electronics was a newly emerging frontier in recent years. However, restricted by the single silver-white appearance of the liquid metal(LM), the colors of currently available printed electronics were rather limited. Here,a new conceptual LM based colorful printed electronics was proposed where electrical wires and circuits with numerous colors can be made via a straightforward, efficient and accurate printing procedure. Firstly, the LM was printed on the substrate to construct a conductive wire. Then it was frozen to a solid. Subsequently, colorful pigments were coated on the originally printed liquid metal conductive wires, which finally were packaged with PDMS. Such multicolored conductive wire exhibits excellent conductivity, and good temperature resistance(do not fade at high temperature). Further, the adhesion mechanism of the mineral pigments on the liquid metal layer was disclosed. And the pigment layer was discovered to well protect the LM from the outside environments, and enhance the durability of the LM conductive wire at the same time. These multicolored liquid metal wires take an aesthetic appearance, excellent printability, flexibility, large conductivity and stable performance, which would significantly enhance the sense of beauty and experience when compared to the conventional printed electronics.     

Perspective on liquid metal enabled space science and technology

With the rapid development of deep space exploration and commercial flight, a series of tough scientific and technological challenges were raised, which urgently require ever advanced technologies to tackle with. Recently, liquid metals, as a kind of newly emerging functional material, are attracting various attention and many breakthroughs have been made on earth. Such a scientific trend also suggests promising approaches for solving those extreme challenges in space environment. To fulfill the increasing needs thus involved, this article is dedicated to systematically introducing liquid metal material and its related disciplines into space science and technology. Firstly, existing application of liquid metal cooling for space nuclear power was summarized. Then, some potential space practices were tentatively put forward, such as liquid metal thermal interface medium,liquid metal phase change material, liquid metal convection cooling, metal alloy thermal storage, liquid metal electromagnetic shielding and liquid metal electronic printing. Fundamental as well as practical issues that would differ with earth were interpreted. Finally, potential liquid metal space experiments were proposed to investigate the liquid metal hydrodynamic characteristic, wettability and phase change mechanism in space physical environment. Overall, liquid metal enabled space science and technology investigation will not only help efficiently solve the current and future space technological problems, but also aid to stimulate the advancement of liquid metal space material science.     

液态油墨制作计量圆光栅的研究

液态油墨又称液态感光油墨,是一种特殊的紫外油墨,通过紫外曝光后固化,和玻璃、金属、塑料薄膜等材料有较好的附着力和牢固度,广泛应用于高精密度电路板、多层板电路的内层蚀刻、各种精密金属标牌腐蚀与电镀印制工艺等行业。但它直接用于制作计量圆光栅未见报道,通过对液态油墨复制工艺的研究,及计量圆光栅制作工艺的对比,详细介绍了液态油墨制作计量圆光栅的制作工艺,试验证明液态油墨制作计量圆光栅是可行的。     

Experiment Study on Castex Process of AS Wire

In order to optimize the Castex process of AS wire, the systematic experiments have been done for differed process parameters with self-made DZJ-II 350 Castex machine. The parameters, such as casting temperature of aluminum, flow of cooling Water, extrusion ratio and the gap between the surface of wheel and that of the mould, have been mainly studied. The results show that with the increase of casting temperature or rotating speed of wheel the measured length of liquid metal zone increases too. However, the length of liquid metal zone decreases with the increase of the flow of cooling water Moreover, the relationship between the extrusion ratio and the extrusion power is studied.     

基于数字微喷的金属粉末三维打印实现方法研究

金属三维打印能够实现复杂功能零件直接制造与净近成型,具有广阔的应用前景和重要的研究价值. 在高精度金属三维打印领域目前以选择性激光烧结(SLS)工艺为主,但由于选择性激光烧结工艺的设备成本高、模型成型时间长、金属粉末材料选择范围窄等原因,限制了其应用范围. 本文提出一种“基于数字微喷与UV光固化相结合的金属粉末三维打印”实现方法,开发出一套完整的硬件平台与软件系统,并进行了相关的实验,验证了工艺的可行性和开发系统的可靠性. 该方法为金属三维打印提供了新的实现方法,具有较高的研究价值和意义.     

数码喷墨印花墨水的研究进展

简要介绍了纺织品数码喷墨印花技术的发展现状以及喷墨印花工艺对墨水的一般技术要求,着重对喷墨印花墨水作了详细的介绍,并将喷墨印花墨水分为墨水和油墨两类。分别描述了墨水和油墨的国内外研究现状以及存在的问题和趋势,尤其对高分子染料作为喷墨印花墨水和油墨的发展作了详细的探讨。纺织品数码喷墨印花墨水的研制以及其应用开发对我国染料和纺织行业的发展有着重要的意义。     

杯[4]芳烃对金属离子的液膜传输

通过杯芳烃衍生物的识别作用可以实现对金属离子的选择性液膜传输．对比研究对叔丁基杯[4]芳烃和四乙酰氧基对叔丁基杯[4]芳烃对不同金属离子的液膜传输行为．发现四乙酰氧基对叔丁基杯[4]芳烃对Ag^ 有较高的传输性能，并重点考察不同因素(源相与吸收相之间的pH梯度、离子浓度)对传输能力的影响．初步探讨杯[4]芳烃及其衍生物作为离子载体的传榆规律及传输机理.     

Electrically driven chip cooling device using hybrid coolants of liquid metal and aqueous solution

Heat dissipation of electronic devices keeps as a tough issue for decades. As the most classical coolant in a convective heat transfer process, water has been widely adopted which however inherits with limited thermal conductivity and relies heavily on mechanical pump. As an alternative, the room temperature liquid metal was increasingly emerging as an important coolant to realize much stronger enhanced heat transfer. However, its thermal capacity is somewhat lower than that of water, which may restrict the overall cooling performance. In addition, the high cost by taking too much amount of liquid metal into the device also turns out to be a big concern for practical purpose. Here, through combining the individual merits from both the liquid metal with high conductivity and water with large heat capacity, we proposed and demonstrated a new conceptual cooling device that integrated hybrid coolants, radiator and annular channel together for chip thermal management. Particularly, the electrically induced actuation effect of liquid metal was introduced as the only flow driving strategy, which significantly simplified the whole system design. This enables the liquid metal sphere and its surrounding aqueous solution to be quickly accelerated to a large speed under only a very low electric voltage. Further experiments demonstrated that the cooling device could effectively maintain the temperature of a hotpot (3.15 W/cm²) below 55ºC with an extremely small power consumption rate (0.8 W). Several situations to simulate the practical working of the device were experimentally explored and a theoretical thermal resistance model was established to evaluate its heat transfer performance. The present work suggests an important way to make highly compact chip cooling device, which can be flexibly extended into a wide variety of engineering areas.     

印刷线路板新工艺的研究

本文采用铜导电股，用丝网漏印法制印刷线路板，对传统的覆铜板腐蚀工艺进行改进，对制板、丝网漏印、固化、电镀等新工艺进行研究，所制作的印刷线路板经测试其性能指标已达到或超过覆铜板印刷线路板的技术要求，这种线路板可用在中低档电器的制作。     

Fe含量和冷却速度对ZL105合金中铁相形成的影响

研究了铁含量和冷却速度对ZL105合金中铁相形成的影响.试验结果表明：随着铁含量的降低,合金中生成的铁相数量逐渐减少,铁相的形貌从含铁量为1.2％时的粗大针相逐渐变化为含铁量为0.3％时细小的铁相;针对铁含量为0.6％的ZL105合金,在采用金属型铸造时,由于冷却速度快,没有铁相形成,而在冷却速度比较慢的耐火砖铸型中,生成的铁相粗大.     

在胶印中印刷压力的分析

印刷压力是印刷机设计以及油墨向承印物表面转移的基础，它不仅是实现印刷过程的根本保证，而且在很大程度上决定着印刷的质量。从包衬材料及印刷过程中使用的纸张、油墨等因素出发，定性或定量分析印刷压力的计算、调节及确定。     

金属物理-化学法制备高纯金属氧化物粉体的研究现状

金属物理-化学法是制备高纯金属氧化物亚微米、纳米级陶瓷粉体的新工艺，文中列举了活性金属粉末直接水解法及金属液雾燃烧法两种方法．从方法的机理、特点、应用范围、改进与完善的方向等方面综述了金属物理-化学法的研究现状，指出了该工艺方法的应用前景．     

啤酒露天发酵罐冷却方式的探讨

本文通过分析啤酒露天发酵罐几种冷却方式,提出了最为经济合理的氨泵供液型式,并对其在工程设计中的应用作了分析和评价。     

无电极电阻率法研究水泥基复合材料的导电机理

采用无电极电阻率法监测了分别掺入碳纤维、钢纤维和碎石骨料的水泥基复合材料在72 h内的电阻率,并用Hymstruc3D建立了微观结构模型分析导电机理。结果表明:水泥浆体的电阻率受电解质液相饱和度、孔隙率及孔结构曲折度的影响。掺入的导电纤维能明显降低水泥基复合材料的电阻率;而掺入骨料时,其电阻率明显增加。水泥基复合材料的导电现象是由水泥浆体中液相离子导电和导电纤维中的电子导电的共同作用所致。水泥基复合材料的电阻率与其导电相的含量密切相关。无电极电阻率法为估算水泥基复合材料中导电相或非导电相的含量提供了新的思路。     

Effect of electric field on the activity and quenching structure of liquid Cu-Al alloys

The activity coefficient of A1 in molten Cu decreases with the increasing of electric current applied to the liquid alloy of Cu-0.2wt%Al. To investigate the mechanism, the quenching experimental results of the liquid A1-Cu alloy show that there is a remarkable change in structure, in which the solute congregates along the current direction especially for DC current. The mechanism of the activity coefficient change of A1 in molten Cu-0.2wt%Al alloy treated by electrical field was discussed. Further, the results also provide an evidence for the short-range-ordered liquid metal.     

3D打印技术中的数据文件格式

3D打印是一种快速成型技术,以数字化模型文件为基础进行建模,并通过逐层打印的方式来实现实体的制造,不同的数据文件格式直接影响加工过程和加工效果。介绍了3D打印的工艺流程与三维模型数据的获取技术,从三维数据文件格式、二维层片文件格式、新型的数据文件格式3个方面系统阐述了3D打印技术中的数据文件格式,并分析了各种数据文件格式的内涵与优缺点。最后,根据目前3D打印的发展给出了未来数据文件格式的发展方向。     

液态金属铝的结构转变模拟研究

采用分子动力学方法对液态金属Al的凝固过程中微观结构转变特性进行了模拟研究。发现在943~50 K的温度区间凝固过程中,与二十面体结构相关的1551键型数目的变化最为显著,对系统结构组态的变化起关键作用。结果表明:随着温度降低,系统有序度增加,无序度下降。