A Novel Low-Cost Stereolithography Process Based on Vector Scanning and Mask Projection for High-Accuracy, High-Speed, High-Throughput and Large-Area Fabrication

2014 ◽  
Author(s):  
Chi Zhou ◽  
Hang Ye ◽  
Feng Zhang
Keyword(s):  
Surface Quality ◽  
High Speed ◽  
Laser Scanning ◽  
Low Cost ◽  
High Surface ◽  
Hybrid Process ◽  
Surface Finishing ◽  
Layer By Layer ◽  
Large Area ◽  
Vector Scanning

Photopolymerization based process is one of the most popular additive manufacturing processes. Two primary configurations for this process are laser based vector by vector scanning (0D) and projection based layer by layer exposing (2D). With the highly focused fine laser, the scanning based process can accomplish very high surface finishing and precision, however, due to the serial nature of scanning, this process suffers from the problem of slow speed. In contrast with laser scanning, projection based process can form the whole layer in one exposure, which leads to higher fabrication efficiency. However, due to the limited resolution of projection device and various optical defects, the surface quality will be significantly deteriorated for large area fabrication. To solve this problem, a novel hybrid process by integrating vector scanning and mask projection has been presented. In this process, laser is focused into a fine spot and used to scan the boundary of the layer, whereas the projector is focused onto a large platform surface and used to form the interior area of the layer. An efficient slicing method is proposed for extracting the contour for laser scanning. A slice to image conversion algorithm is also developed to convert the offset contour to grayscale image for mask projection. Experimental results have verified that the proposed hybrid process can significantly improve the fabrication speed without losing the surface quality.

A Novel Low-Cost Stereolithography Process Based on Vector Scanning and Mask Projection for High-Accuracy, High-Speed, High-Throughput, and Large-Area Fabrication

2015 ◽  
Vol 15 (1) ◽  
Author(s):  
Chi Zhou ◽  
Hang Ye ◽  
Feng Zhang
Keyword(s):  
Surface Quality ◽  
High Speed ◽  
Laser Scanning ◽  
Low Cost ◽  
High Surface ◽  
Hybrid Process ◽  
Surface Finishing ◽  
Layer By Layer ◽  
Large Area ◽  
Vector Scanning

Photopolymerization based process is one of the most popular additive manufacturing (AM) processes. Two primary configurations for this process are laser based vector by vector scanning (0D) and projection based layer by layer exposing (2D). With the highly focused fine laser, the scanning based process can accomplish very high surface finishing and precision, however, due to the serial nature of scanning, this process suffers from the problem of slow speed. In contrast with laser scanning, projection based process can form the whole layer in one exposure, which leads to higher fabrication efficiency. However, due to the limited resolution of projection device and various optical defects, the surface quality will be significantly deteriorated for large area fabrication. To solve this problem, a novel hybrid process by integrating vector scanning and mask projection has been presented. In this process, laser is focused into a fine spot and used to scan the boundary of the layer, whereas the projector is focused onto a large platform surface and used to form the interior area of the layer. An efficient slicing method is proposed for extracting the contour for laser scanning. A slice to image conversion algorithm is also developed to convert the offset contour to grayscale image for mask projection. Experimental results have verified that the proposed hybrid process can significantly improve the fabrication speed without losing the surface quality.

An Investigation onto Polydimethylsiloxane (PDMS) Printing Plate of Multiple Functional Solid Line by Flexographic

2013 ◽  
Vol 844 ◽  
pp. 158-161 ◽  
Author(s):  
M.I. Maksud ◽  
Mohd Sallehuddin Yusof ◽  
M. Mahadi Abdul Jamil
Keyword(s):  
Laser Ablation ◽  
Line Width ◽  
High Speed ◽  
Printed Electronics ◽  
Low Cost ◽  
Flexible Substrates ◽  
Large Area ◽  
Printing Plate ◽  
Roll To Roll ◽  
Printing Processes

Recently low cost production is vital to produce printed electronics by roll to roll manufacturing printing process like a flexographic. Flexographic has a high speed technique which commonly used for printing onto large area flexible substrates. However, the minimum feature sizes achieved with roll to roll printing processes, such as flexographic is in the range of fifty microns. The main contribution of this limitation is photopolymer flexographic plate unable to be produced finer micron range due to film that made by Laser Ablation Mask (LAMs) technology not sufficiently robust and consequently at micron ranges line will not be formed on the printing plate. Hence, polydimethylsiloxane (PDMS) is used instead of photopolymer. Printing trial had been conducted and multiple solid lines successfully printed for below fifty microns line width with no interference between two adjacent lines of the printed images.

Raster Scanning Laser and UV Processing of nanocrystalline TiO2 Films for Sintering in Dye Solar Cells: Device Performance, Throughput and Embodied Energy

2012 ◽  
Vol 1447 ◽  
Author(s):  
Girolamo Mincuzzi ◽  
Valerio Zardetto ◽  
Luigi Vesce ◽  
Malte Schulz-Ruhtenberg ◽  
Arnold Gillner ◽  
...  
Keyword(s):  
Solar Cells ◽  
Laser Scanning ◽  
Low Cost ◽  
Standard Procedure ◽  
Embodied Energy ◽  
Large Area ◽  
Nanocrystalline Tio2 ◽  
Plastic Substrates ◽  
Dye Solar Cells ◽  
Uv Lamp

ABSTRACTA crucial step in Dye Solar Cell (DSC) fabrication is the sintering of the TiO2 layer which needs to guarantee good electromechanical bonding between nanoparticles whilst maintaining sufficiently large porosity to yield performing devices. The standard procedure for TiO2 sintering requires firing in an oven at ∼ 500°C. An alternative procedure consists in utilizing laser scanning processing which has the advantageous potential of being noncontact, local, low cost, rapid, selective, automated and scalable. We analyzed and optimised a laser process for the sintering of the TiO2 layers in dye solar cells analyzing temperature profiles, throughput and the embodied energy. The development of electronic and photovoltaic devices on plastic substrates is of considerable interest due to the advantages they bring in terms of flexibility and easy processing for lightweight, low-cost large-area applications. An alternative sintering procedure compatible with flexible substrates and large area processing consists in utilizing a UV lamp. We subjected TiO2 pastes deposited on conductive transparent substrates to UV irradiation. Fully plastic devices fabricated through this method showed efficiencies of 4%.

Design and Implementation of Colloidal Quantum Dot Field-Effect Transistors

2014 ◽  
Vol 668-669 ◽  
pp. 818-821
Author(s):  
Hai Yan Wang ◽  
Ya Ting Zhang ◽  
Xiao Xian Song ◽  
Lu Fan Jin ◽  
Hai Tao Dai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Field Effect Transistors ◽  
Low Cost ◽  
Structure Design ◽  
Layer By Layer ◽  
Gate Bias ◽  
Large Area ◽  
Photoconductive Detectors ◽  
Pbs Quantum Dots

With the breakthrough of mobility in quantum dot electric field transistors (Q-EFTs), the potential application in these functional devices has revealed and been paid more attentions, due to flexibility in design, low cost, facility for processing and large area. One of the most important applications of FETs is the photoconductive detector. However, these functional FETs have less been reported. In this work, colloidal PbS Q-FETs were successfully fabricated by reasonable structure design and layer-by-layer depositon technique PbS quantum-dots. The bipolar property was demonstrated by the output and transfer characteristics, as devices work in I and III quadrants simultaneously. The mobilities of electron and hole are 0.16 cm2/(V⋅s) and 0.28 cm2/(V⋅s), respectively. Q-FETs work as photoconductive detectors at both positive and negative gate bias voltages. Under constant gate bias, photocurrent increase exponentially with the intensity of light. The responding region consisted with the absorption range of PbS quantum dots. A linearity was found in drain voltage and incidence of laser power, the ratio was attributing to 0.0019 (μW⋅V)-1.

Experimental Study of Ignition and Combustion Characteristics of Mixed Rice Straw and Sewage Sludge Solid and Hollow Spherical Pellets in a Plasma Combustion System

2019 ◽  
Vol 797 ◽  
pp. 327-335 ◽  
Author(s):  
Mohamed E. Mostafa ◽  
Hao Tang ◽  
Jun Xu ◽  
Huan Ying Chi ◽  
Kai Xu ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Rice Straw ◽  
High Speed ◽  
High Surface ◽  
Combustion Process ◽  
Combustion Characteristics ◽  
Combustion System ◽  
Large Area ◽  
Char Combustion ◽  
Ignition And Combustion

In this work, the ignition and combustion characteristics of mixed rice straw and sewage sludge pellets in air atmosphere were investigated using a plasma combustion system. One common pellet shape (solid spherical pellet) and another new shape (hollow spherical) are used in this study. High-speed camera was used to record and observe ignition and combustion process of pellets. In case of hollow pellets, the shape and distribution of flame are found to be better compared to solid pellets. Also, it is clear that the values of volatile combustion times in case of hollow pellets are low compared to solid pellets. The overall heat transfer enhanced in case of hollow pellet due to the large area subjected to hot gases and the high surface to volume ratio. Hollow pellet consumed less time for internal ignition and volatiles char combustion compared to solid pellet. Volatiles and char combustion lasted for 63.05 and 61 s, respectively for hollow pellet while these values were found to be 72.8 and 83 s, respectively for solid pellet.

scholarly journals Theoretical Uniformity Analysis and Improvement of Spray Deposition by Mixing Nozzles with Heating Conditions

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 81
Author(s):  
Xuran Dong ◽  
Xiaolong Pan ◽  
Xianxian Gao ◽  
Haisheng Fang
Keyword(s):  
High Speed ◽  
Heating Temperature ◽  
Spray Deposition ◽  
Low Cost ◽  
Spray Coating ◽  
Deposition Process ◽  
Test Method ◽  
Large Area ◽  
Orthogonal Test Method ◽  
Experimental Trials

Spray coating is widely used in the manufacture of deposited layers of electronic devices due to its unique advantages of high-speed deposition over a large area. To improve the spray deposition process for further low-cost and uniform production, the uniformity of the spray deposition should be systematically investigated. The current study, however, mainly focuses on the experimental trials with few numerical directions especially for the mixing nozzle sprayers with heating conditions. In the paper, we conduct a theoretical study on the uniformity of the internal and external mixing nozzles. The influencing factors include the initial angle, the total ink flow rate, the transporting gas velocity and the distance from the nozzle to the substrate. Then, the orthogonal test method is adopted to obtain the optimal combination of the parameters. Finally, the effects of different heating modes on the uniformity have been further studied. The results show that these factors influence the uniformity with the two types of nozzles to a different degree. The evaporation of the atomized droplets can effectively improve the uniformity in a certain temperature range. The heating temperature with the highest uniformity is various depending on the heating modes, which should be carefully addressed during the actual production.

scholarly journals Computer Numerical Controlled Grinding and Physical Vapor Deposition for Fused Deposition Modelled Workpieces

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Fulvio Lavecchia ◽  
Gianluca Percoco ◽  
Eujin Pei ◽  
Luigi Maria Galantucci
Keyword(s):  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
High Surface ◽  
Extrusion Process ◽  
Surface Finishing ◽  
Fused Deposition Modelling ◽  
Layer By Layer ◽  
Fused Deposition ◽  
Test Pieces ◽  
Pvd Coating

The use of additive manufacturing (AM) enables companies to directly produce complex end-use parts. Fused deposition modelling (FDM) is an AM technology based on an extrusion process of fabricating parts. This layer-by-layer method results in a poor surface finish, and as a result, manual finishing is often required, which consequentially reduces the definition of the geometrical features. This research proposes a novel way of achieving high surface finishing by using additive and finishing processes, followed by a physical vapor deposition (PVD) coating. Two test pieces were produced, the first one was subjected to computer numerical controlled (CNC) mechanical grinding with appropriate grades of grindstones; the second one was subjected to microsandblasting to remove excess material and the stair-stepping effect. Both test pieces were then subjected to a PVD coating process to provide a metal thin film. To benchmark the test pieces, the authors used a coordinate measure machine for dimensions and a roughness meter to verify the effectiveness of this postprocessing approach.

Micropatterned freestanding magnetron sputtered Mg-alloy scaffolds

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
David Haffner ◽  
Christiane Zamponi ◽  
Rodrigo Lima de Miranda ◽  
Eckhard Quandt
Keyword(s):  
Mechanical Properties ◽  
Magnetron Sputtering ◽  
Surface Quality ◽  
Spatial Resolution ◽  
High Surface ◽  
Chemical Polishing ◽  
Surface Finishing ◽  
High Reproducibility ◽  
High Surface Quality ◽  
Sem Investigation

AbstractFreestanding scaffolds were fabricated of Mg5W (wt.% yttrium) alloy using magnetron sputtering technology. Appropriate method was found to produce scaffolds with high reproducibility, spatial resolution of 1 μm and good mechanical properties. Two different techniques were used for surface finishing, microblasting and chemical polishing. SEM investigation showed high surface quality after chemical polishing while microblasting influenced mechanical properties of the Mg5W alloy. Magnetron sputtering offers a high potential for the production of microstructured scaffolds.

scholarly journals Single-Fiber Bidirectional Optical Data Links with Monolithic Transceiver Chips

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Alexander Kern ◽  
Sujoy Paul ◽  
Dietmar Wahl ◽  
Ahmed Al-Samaneh ◽  
Rainer Michalzik
Keyword(s):  
High Speed ◽  
Low Cost ◽  
Full Duplex ◽  
Optical Data ◽  
Cavity Surface ◽  
Material System ◽  
Large Area ◽  
Core Diameter ◽  
Data Rates ◽  
Electrooptical Properties

We report the monolithic integration, fabrication, and electrooptical properties of AlGaAs-GaAs-based transceiver (TRx) chips for 850 nm wavelength optical links with data rates of multiple Gbit/s. Using a single butt-coupled multimode fiber (MMF), low-cost bidirectional communication in half- and even full-duplex mode is demonstrated. Two design concepts are presented, based on a vertical-cavity surface-emitting laser (VCSEL) and a monolithically integrated p-doped-intrinsic-n-doped (PIN) or metal-semiconductor-metal (MSM) photodetector. Whereas the VCSEL-PIN photodiode (PD) chips are used for high-speed bidirectional data transmission over 62.5 and 50 μm core diameter MMFs, MSM TRx chips are employed for 100 or 200 μm large-area fibers. Such a monolithic transceiver design based on a well-established material system and avoiding the use of external fiber coupling optics is well suited for inexpensive and compact optical interconnects over distances of a few hundred meters. Standard MMF networks can thus be upgraded using high-speed VCSEL-PIN transceiver chips which are capable to handle data rates of up to 10 Gbit/s.

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