Reducing lateral stair-stepping defects in liquid crystal display-based vat photopolymerization by defocusing the image pattern

Shan, Yujie; Krishnakumar, Aravind; Qin, Zehan; Mao, Huachao

doi:10.1016/j.addma.2022.102653

Cited by 17 publications

(18 citation statements)

References 29 publications

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“…A photocurable resin (details in the Experimental Section; Table S3, Supporting Information) was used to fabricate a flexible patterned platform for pressure sensors, and the printing process is elaborated in the Experimental Section, following our previous reports. [ 63 ] The customized micropatterned structures with the desired performance can be simply 3D‐printed without a mold. Figure 1e displays several 3D‐printed structures ranging from single‐scale (dome, spike, and pillar) to multiscale (spikes and pillars on a dome) patterns.…”

Section: Resultsmentioning

confidence: 99%

“…[59] More importantly, the curing light can be effectively patterned with millions of pixels, using a digital micromirror device (DMD) [60][61][62] or liquid-crystal display (LCD). [63] This printing principle indicates millions of features are simultaneously solidified in seconds, which are orders of magnitude faster than nozzle-based printing methods. [60] Various functional materials can be processed using the vat photopolymerization (VPP) process, including flexible photocurable resin and nanofillers.…”

Section: Introductionmentioning

confidence: 99%

“…This advancement has been coined as large-area high-resolution 3D printing. [61,63,67,68] Here, we demonstrate a mold-free fabrication of a flexible pressure sensor by integrating high-resolution 3D printing and conformal coating of conducting polymer films. LCD-based VPP was leveraged to manufacture the pressure sensor's substrate with a multiscale pattern, which was seamlessly coated with a nanoscale sensing element using gas-phase conductive polymer coating.…”

Section: Introductionmentioning

confidence: 99%

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Mold‐Free Manufacturing of Highly Sensitive and Fast‐Response Pressure Sensors Through High‐Resolution 3D Printing and Conformal Oxidative Chemical Vapor Deposition Polymers

Baek,

Shan,

Mylvaganan

et al. 2023

Advanced Materials

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In this work, w e showcase a new manufacturing paradigm to exclude conventional mold‐dependent manufacturing of pressure sensors, which typically requires a series of complex and expensive patterning processes. Our mold‐free manufacturing leverages high‐resolution 3D printed multiscale microstructures as substrate and a gas‐phase conformal polymer coating technique to complete the mold‐free sensing platform. The array of dome and spike structures with a controlled spike density of a 3D‐printed substrate ensures a large contact surface with pressures applied and extended linearity in a wider pressure range. For uniform coating of sensing elements on the microstructured surface, oxidative chemical vapor deposition is employed to deposit a highly conformal and conductive sensing element, poly(3,4‐ethylenedioxythiophene) at low temperatures (< 60 °C). The fabricated pressure sensor reacts sensitively to various ranges of pressures (up to 185 kPa−1) depending on the density of the multiscale features and shows an ultra‐fast response time (∼36 μs). The mechanism investigations through the finite element analysis identify the effect of the multiscale structure on the figure‐of‐merit sensing performance. Our unique findings are expected to be of significant relevance to the technology that requires higher sensing capability, scalability, and facile adjustment of a sensor geometry in a cost‐effective manufacturing manner.This article is protected by copyright. All rights reserved

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mold‐Free Manufacturing of Highly Sensitive and Fast‐Response Pressure Sensors Through High‐Resolution 3D Printing and Conformal Oxidative Chemical Vapor Deposition Polymers

Baek,

Shan,

Mylvaganan

et al. 2023

Advanced Materials

Self Cite

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“…Such a limitation, which easily impairs the vertical printing precision of intestinal stents and leads to surface inconsistency, has not yet been solved. [ 13,14 ]…”

Section: Introductionmentioning

confidence: 99%

“…Such a limitation, which easily impairs the vertical printing precision of intestinal stents and leads to surface inconsistency, has not yet been solved. [13,14] Moreover, in clinical practice, a fistula stent is expected to be flexible enough for easy deformation and implantation through an EAF orifice. Meanwhile, when located in the intestinal lumen, the stent should be stiff to maintain the tubular shape and resist intestinal contractility (Figure 1a).…”

Section: Introductionmentioning

confidence: 99%

Whole Model Path Planning‐Guided Multi‐Axis and Multi‐Material Printing of High‐Performance Intestinal Implantable Stent

Wang

Huang

et al. 2023

Adv Healthcare Materials

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The problems of step effects, supporting material waste, and conflict between flexibility and toughness for 3D printed intestinal fistula stents are not yet resolved. Herein, the fabrication of a support‐free segmental stent with two types of thermoplastic polyurethane (TPU) using a homemade multi‐axis and multi‐material conformal printer guided with advanced whole model path planning is demonstrated. One type of TPU segment is soft to increase elasticity, and the other is used to achieve toughness. Owing to advancements in stent design and printing, the obtained stents present three unprecedented properties compared to previous three‐axis printed stents: i) Overcoming step effects; ii) Presenting comparable axial flexibility to a stent made of a single soft TPU 87A material, thus increasing the feasibility of implantation; and iii) Showing equivalent radial toughness to a stent made of a single hard TPU 95A material. Hence, the stent can resist the intestinal contractive force and maintain intestinal continuity and patency. Through implanting such stents to the rabbit intestinal fistula models, therapeutic mechanisms of reducing fistula output and improving nutritional states and intestinal flora abundance are revealed. Overall, this study develops a creative and versatile method to improve the poor quality and mechanical properties of medical stents.

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Pixel‐Level Grayscale Manipulation to Improve Accuracy in Digital Light Processing 3D Printing

Montgomery

Demoly

Zhou

et al. 2023

Adv Funct Materials

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Digital light processing (DLP) is a widely used additive manufacturing technique for functional applications due to its high accuracy and print speeds. However, a variety of factors such as pixel size, motion stage resolution, optical focus, and chemical properties of the resin limit DLP's minimum resolution. Recently, research into locally varying light intensities has led to the emergence of grayscale DLP printing, which offers new capabilities including sub‐pixel manipulation of the printed shape. Here, a methodology is developed to enhance accuracy beyond what is typically capable for a given projector resolution by using pixel‐level grayscale control to create round features from sharp pixels. A numerical representation of the DLP pixel shape is developed to account for the effects of the incident light patterns. A reaction‐diffusion model is then used to predict the printed shapes before and after grayscale enhancement. This model is used to determine the optimal pixel intensities to match a target shape. Finally, the minimum feature size allowed by the proposed method is explored. The promising results represent an important step forward in raising DLP printing to higher accuracy, which will allow the fabrication of functional and structural components with smaller features or smoother faces.

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Reducing lateral stair-stepping defects in liquid crystal display-based vat photopolymerization by defocusing the image pattern

Cited by 17 publications

References 29 publications

Mold‐Free Manufacturing of Highly Sensitive and Fast‐Response Pressure Sensors Through High‐Resolution 3D Printing and Conformal Oxidative Chemical Vapor Deposition Polymers

Mold‐Free Manufacturing of Highly Sensitive and Fast‐Response Pressure Sensors Through High‐Resolution 3D Printing and Conformal Oxidative Chemical Vapor Deposition Polymers

Whole Model Path Planning‐Guided Multi‐Axis and Multi‐Material Printing of High‐Performance Intestinal Implantable Stent

Pixel‐Level Grayscale Manipulation to Improve Accuracy in Digital Light Processing 3D Printing

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