自动检测套印误差的研究

针对单张纸多色胶印机的套印不准问题,基于模板匹配理论及统计学原理,提出了自动检测套印误差的“新模板匹配算法”。该算法利用十字线图像的固有特征,通过统计差值图像信息,获得十字线的位置参数。实验结果表明,该算法有效且可行。     

平网印花机对花检测系统图像处理算法的研究

探讨平网印花机生产过程中对花误差的快速检测问题,设计了基于TI公司DM642 DSP的自动对花检测系统图像处理算法.经与本课题开发的专用图像处理控制板配合运行验证,算法简单、程序运行效率高、快速稳定,达到了实时对花检测的效果.     

Specific Heat Capacity and Thermal Conductivity Measurements of PLA-Based 3D-Printed Parts with Milled Carbon Fiber Reinforcement

This research focuses on the thermal characterization of 3D-printed parts obtained via fused filament fabrication (FFF) technology, which uses a poly(lactic acid) (PLA)-based filament filled with milled carbon fibers (MCF) from pyrolysis at different percentages by weight (10, 20, 30 wt%). Differential scanning calorimetry (DSC) and thermal conductivity measurements were used to evaluate the thermal characteristics, morphological features, and heat transport behavior of the printed specimens. The experimental results showed that the addition of MCF to the PLA matrix improved the conductive properties. Scanning electron microscopy (SEM) micrographs were used to obtain further information about the porosity of the systems.     

High efficiency screen-printed n-type silicon solar cell using co-diffusion of APCVD boron emitter and POCl3 back surface field

We present the fabrication and analysis of Passivated Emitter and Rear Totally Diffused (PERT) solar cells on n-type silicon using a co-diffusion process. In a single high temperature step, a BSG/SiO_x stack deposited by APCVD and a POCl₃ back surface field diffuse into the wafer to form the boron doped emitter and phosphorus doped back surface field. The SiO_x layer on top of BSG acts as a masking layer to prevent cross-doping of phosphorus as well as a blocking layer for boron out-diffusion. This resulted in an initial sheet resistance of 76 Ω/□ with good uniformity and a final p⁺ emitter sheet resistance of 97 Ω/□ after boron rich layer removal. Additionally, bulk lifetime was investigated before and after the high temperature step that resulted in an increase from 1.2 ms to 1.5 ms due to a POCl₃ gettering effect. A peak cell efficiency of 20.3% was achieved and each recombination component in terms of saturation current density was calculated and analyzed to understand the cell for further efficiency enhancement.     

无墨喷水可重复打印纸工业化制备

“无墨喷水打印”技术因其绿色环保的特点引起了广泛关注,推进无墨喷水可重复打印纸的产业化具有重要的意义。 本文以具有水致变色性质的吲哚并[2,1-b]噁唑啉染料分子(TM)为例,选定聚对苯二甲酸乙二醇酯(PET)代替滤纸基材,通过筛选合适的表面活性剂、调整染料用量以及涂层厚度,探究并得到了一种无墨喷水可重复打印纸的工业化制备工艺。 结果表明,利用优化后的制备工艺得到的无墨喷水可重复打印纸具有良好的可重复书写性能,并通过小量生产测试验证该制备工艺可以应用于实际工业生产。     

石墨烯基墨水的制备及其在印刷电子中的应用

 石墨烯材料具有优异的导电性、柔性、化学稳定性等特征,在印刷电子领域中具有广阔的应用前景。概述了石墨烯材料的宏量制备方法,结合喷墨打印、丝网印刷和3D打印等方法介绍了石墨烯墨水制备的技术特点和要求,展示了石墨烯在印刷电子功能器件中的应用,主要类型包括透明导电薄膜、柔性电路、超级电容器和可穿戴传感器等。总结了该领域当前研究进展中存在的问题和挑战,从材料设计、加工制备和器件应用方面进行了展望。在未来发展中可通过丰富石墨烯打印线路的结构形式,并注重利用组装的策略增强结构有序性,实现多功能、高性能的器件制备和应用。     

无托槽隐形正畸矫治器牙模轻量化

为了降低无托槽隐形正畸矫治器的制造成本,基于增材制造设计(DfAM)准则对光固化3D打印的树脂牙颌模型进行轻量化研究。运用宏观拓扑优化和介观点阵填充,建立7种优化的牙模,通过ANSYS有限元仿真选取3种最佳的牙模进行3D偏差实验研究,对其在压膜环境下的物理和力学性能进行评估。结果表明,在保证隐形矫治器的制造精度前提下,二维蜂窝点阵填充的牙模相比初始牙模质量降比达到21.67%,是最佳的轻量化设计方案。     

3D‐Printed Titanium Cage with PVA‐Vancomycin Coating Prevents Surgical Site Infections (SSIs)

Many coating materials have been studied to prevent surgical site infections (SSIs). However, antibacterial coating on surfaces show weak adhesion using the traditional titanium (Ti) cage, resulting in low efficacy for preventing SSIs after spinal surgery. Herein, a 3D‐printed Ti cage combined with a drug‐releasing system is developed for in situ drug release and bacteria killing, leading to prevention of SSIs in vitro and in vivo. First, a 3D‐printed Ti cage is designed and prepared by the Electron Beam Melting (EBM) method. Second, polyvinyl alcohol (PVA) containing hydrophilic vancomycin hydrochloride (VH) is scattered across the surface of 3D‐printed porous Ti (Ti‐VH@PVA) cages. Ti‐VH@PVA cages show an efficient drug‐releasing profile and excellent bactericidal effect for three common bacteria after more than seven days in vitro. In addition, Ti‐VH@PVA cages exhibit reliable inhibition of inflammation associated with Staphylococcus aureus and effective bone regeneration capacity in a rabbit model of SSIs. The results indicate that Ti‐VH@PVA cages have potential advantages for preventing SSIs after spinal surgery.     

Mechanical evaluation of polymeric filaments and their corresponding 3D printed samples

3D printing technologies permits to produce functional parts with complex geometries, optimized topologies or enhanced internal structures. The relationship between mechanical performance and manufacturing parameters should be exhaustively analyzed to warrant the long term success of printed products. In this work, the mechanical performance of filaments based on acrylonitrile butadiene styrene (ABS), polylactic acid (PLA) and polylactic acid/polyhydroxyalkanoate (PLA/PHA) was investigated and also compared with their corresponding 3D printed samples. In general, the specimen dimensional deviations were found to be within the tolerances defined by the standard testing protocols. Density values revealed a high level of filament fusion promoting a nearly solid internal structure. The filaments exhibited improved tensile performance with respect to their corresponding printed samples. Tensile and bending performance looked quite independent of the raster angle. Izod impact behavior was increased, for ABS systems printed with the ±45° raster orientation. Quasi-static fracture tests displayed improved crack initiation resistance with the 0°/90° raster angle. The crack propagation observed for the ±45° specimens, through the bonding of the inter-layers, suggests weak entanglements.     

Polypropylene Copolymers Designed for Fused Filament Fabrication 3D‐Printing

Several chemical properties which influence the printability for fused filament fabrication 3D‐printing are derived from analyses of commercially available filaments. In preliminary experiments, polymerization conditions are optimized and suitable monomers and selectivity control agents (donors) are selected. An experimental series in which propene is copolymerized with the comonomers 1‐butene and 1‐hexene with an industrial Ziegler–Natta catalyst will be discussed here. The experiments are planned using design of experiments. Based on a split‐plot design, the design is adapted for mixtures and the combination of homo‐ and copolymerization. The observed factors, besides the mixture composition, are hydrogen partial pressure and the amount of donor. The obtained polymers are analyzed by means of high‐temperature size exclusion chromatography, differential scanning calorimetry, and rheology. 1‐Butene copolymers show good printing results and promising properties almost matching the desired ones. The targeted polymer properties are achieved within certain limits. 1‐Hexene copolymers result in lower molecular masses while crystallinity remains slightly higher, which does not match with the desired profile. Beneficial properties are likely to be achieved within a wider factor range, for example, higher comonomer amount and lower hydrogen partial pressure.