Large Size Fabrication Research Articles

Mixed mode interfacial crack energy estimation of glass interposer and SiNx coatings by using fracture mechanics based computer methods and experimental validations

Glass-based interposer is a promising candidate for novel 3D-IC integrations because of its characteristics, such as low cost, low coefficient of thermal expansion, smooth surface quality, and large size fabrication. However, an inherent behavior of brittle material such as glass is its low fracture toughness, which easily induces both interfacial delamination and fracture failure modes, particularly for bonds with neighboring passivation coating of silicon nitride (SiNx). Accordingly, this research proposes a simulated methodology based on the index of interfacial strain energy released rate (G-value) to estimate the glass/SiNx interface using a J-integral approach and modified virtual crack closure technique. Adhesion measurement of glass/SiNx was also implemented by means of four-point bending architecture to validate the predicted accuracy. The results show that a 17.95 J/m2 of G-value for aforementioned interface is obtained. A higher modulus of SiNx coating as determined by different deposited conditions utilized at the concerned glass/SiNx interface also had an effect on the critical fracture energy of the crack after it begins to advance.

(Invited) Cost-Effective Fabrication of Nanostructured Electrodes for High-Performance Flexible Supercapacitors

The blooming market of portable and wearable electronic devices has triggered research interest in energy storage devices that combine both high performance and attractive form factors. Planar supercapacitors are considered as favorable alternatives or complements to batteries, especially to serve as highly flexible, environmentally-friendly and high performance energy storage devices for portable and wearable electronics. In this work, a scalable and printable method was developed to fabricate flexible planar supercapacitors. By using a cost-effective inkjet printing technique, novel and unique hierarchical Nickel (Ni)@Manganese dioxide (MnO2) nanocoral structures were constructed as the interdigitated electrodes on flexible substrates. The as-fabricated flexible all-solid-state planar supercapcacitor achieved an areal capacitance of 52.9 mF cm-2 with enhanced specific power and energy, and such a performance parameter is among the highest in literature for the same category of devices. More interestingly, the inkjet printing technique realized pattern designs with excellent versatility and working supercapacitors with various artistically designed patterns are demonstrated here. Meanwhile, the high scalability of such printable method was also demonstrated by fabrication of large size “power papers”, which successfully served as energy storage devices in wearable self-powered system to power up light emitting and gas detection devices.

Design and accuracy analysis of a metamorphic CNC flame cutting machine for ship manufacturing

The current research of processing large size fabrication holes on complex spatial curved surface mainly focuses on the CNC flame cutting machines design for ship hull of ship manufacturing. However, the existing machines cannot meet the continuous cutting requirements with variable pass conditions through their fixed configuration, and cannot realize high-precision processing as the accuracy theory is not studied adequately. This paper deals with structure design and accuracy prediction technology of novel machine tools for solving the problem of continuous and high-precision cutting. The needed variable trajectory and variable pose kinematic characteristics of non-contact cutting tool are figured out and a metamorphic CNC flame cutting machine designed through metamorphic principle is presented. To analyze kinematic accuracy of the machine, models of joint clearances, manufacturing tolerances and errors in the input variables and error models considering the combined effects are derived based on screw theory after establishing ideal kinematic models. Numerical simulations, processing experiment and trajectory tracking experiment are conducted relative to an eccentric hole with bevels on cylindrical surface respectively. The results of cutting pass contour and kinematic error interval which the position error is from–0.975 mm to +0.628 mm and orientation error is from–0.01 rad to +0.01 rad indicate that the developed machine can complete cutting process continuously and effectively, and the established kinematic error models are effective although the interval is within a ‘large’ range. It also shows the matching property between metamorphic principle and variable working tasks, and the mapping correlation between original designing parameters and kinematic errors of machines. This research develops a metamorphic CNC flame cutting machine and establishes kinematic error models for accuracy analysis of machine tools.

大尺寸1064 nm 波段HfO2/SiO2高损伤阈值

大尺寸1064 nm 波段HfO₂/SiO₂高损伤阈值

A prediction model of layer geometrical size in wire and arc additive manufacture using response surface methodology

Wire and arc additive manufacture has received much concern for its unique advantages in fabrication of large size near net shape components. But the flexibility nature of free arc and time-varying environmental conditions synergistically make shaping path complicated and mutable. In this paper, central composite rotatable experimental design was applied to clarify the mutual relation between input variables (peak current, wire feed speed, and travel speed) and their responses (bead height and width). Moreover, a predicting model was developed, and the validity of the model has been checked by analysis of variance (ANOVA) technique. By using the developed mathematical model, the bead height and width of a single layer are predicted with 95 % confidence level according to the pre-set process parameters. Vice versa, control strategies are proposed to keep the subsequent layer geometrical size unchanged from the former one. A set of process parameters with a desirability of 0.971 is advised basing on the model when the bead height is expected to be 2 mm and the optimum technological parameters, I p = 160A, v T = 0.23 m/min, v w = 4.91 m/min, have been verified by the confirmatory experiment.

Fabrication of Large Size Ex Vivo-Produced Oral Mucosal Equivalents for Clinical Application.

The soft tissue reconstruction of significant avulsed and/or surgically created tissue defects requires the ability to manufacture substantial soft tissue constructs for repair of the resulting wounds. In this study, we detail the issues that need to be addressed in upsizing the manufacture of larger tissue-engineered devices (ex vivo-produced oral mucosa equivalent [EVPOME]) in vitro from a methodology previously used for smaller constructs. The larger-sized EVPOME, consisting of autologous human oral keratinocytes and a dermal substitute, AlloDerm(®), was fabricated for the purpose of reconstructing large clinical defects. Regulated as an autologous somatic cell therapy product, the fabrication process abided by current Good Manufacturing Practices and current Good Tissue Practices as required by the Center for Biologics Evaluation and Research (CBER) of the United States Food and Drug Administration (FDA). Successful fabrication of large EVPOMEs utilized a higher cell seeding density (5.3×10(5) cells/cm(2)) with a relatively thinner AlloDerm, ranging from 356.6 to 508.0 μm in thickness. During the air-liquid interface culture, the thickness of the scaffold affected the medium diffusion rate, which, in turn, resulted in changes of epithelial stratification. Histologically, keratinocyte progenitor (p63), proliferation (Ki-67), and late differentiation marker (filaggrin) expression showed differences correlating with the expression of glucose transporter-1 (GLUT1) in the EVPOMEs from the thickest (550-1020 μm) to the thinnest (228.6-330.2 μm) AlloDerm scaffold. Glucose consumption and 2-deoxyglucose (2DG) uptake showed direct correlation with scaffold thickness. The scaffold size and thickness have an impact on the cellular phenotype and epithelial maturation in the manufacturing process of the EVPOME due to the glucose accessibility influenced by the diffusion rate. These outcomes provide basic strategies to manufacture a large-sized, healthy EVPOME graft for reconstructing large mucosa defects.