Additive Manufacturing (AM) or 3D printing is a process, based on different technologies, for the design and fabrication of three-dimensional objects, an alternative to conventional subtractive manufacturing. AM enables cost-effective manufacturing especially for complex geometries, potentially with lower environmental impacts compared to conventional processes, due to design flexibility and reduced waste. These advantages have drawn the attention of various industrial sectors, for a variety of applications. Currently, several AM technologies are being used to manufacture lightweight, functional, and non-functional parts. Among them, Digital Light Processing (DLP) is one of the most recent and promising technologies for producing high-definition functional and non-functional parts. When compared to stereolithography (SLA), which is based on a laser source for voxel-by-voxel polymerization, one of the major advantages of DLP is the use of a high-resolution source, curing an entire layer with one projection at each step, thus reducing the overall printing time. Initially developed for producing prototypes using pure photopolymers (resins), the technology has been recently tested to print ceramic and metal suspensions. Currently, the technology is being used to produce 3D parts using functional materials, such as elastomers, conductive polymers, shape memory polymers, biopolymers and piezoelectric materials. These photocurable, environmentally responsive materials add up another dimension to the printed part extending 3D printing to 4D printing. In this thesis, the novelties and peculiarities of DLP are highlighted in contrast to other AM technologies. Further, it covers various aspects of the DLP printing process including material preparation, insight into light-matter interaction during printing, and applications together with the advancements in DLP technology. The study also focuses on printing optimization for pure photopolymers, as well as ceramic and metal suspensions. a simple methodology based on preliminary printing tests of single layers is proposed, to identify the material properties, including the penetration depth and critical energy. Such information is the base to draw a printing map using layer thickness and exposure time as independent variables: as such, a printing space is defined within the constraint of material printability, thus ensuring optimal polymerization during three-dimensional object printing.

La additive manufacturing (AM) o stampa 3D è un processo, basato su diverse tecnologie, per la progettazione e la fabbricazione di oggetti tridimensionali, un'alternativa alla convinzionale subtractive manufacturing. La AM consente una produzione conveniente soprattutto per geometrie complesse, potenzialmente con impatti ambientali inferiori rispetto ai processi convenzionali, grazie alla flessibilità di progettazione e alla riduzione degli sprechi. Questi vantaggi hanno attirato l'attenzione di diversi settori industriali, per svariate applicazioni. Attualmente, diverse tecnologie AM vengono utilizzate per produrre parti leggere, funzionali e non funzionali. Tra questi, il Digital Light Processing (DLP) è una delle tecnologie più recenti e promettenti per la produzione di parti funzionali e non ad alta definizione. Rispetto alla stereolithography (SLA), che si basa su una sorgente laser per la polimerizzazione voxel per voxel, uno dei principali vantaggi del DLP è l'uso di una sorgente ad alta risoluzione, che polimerizza un intero strato con una proiezione ad ogni passaggio, riducendo così il tempo di stampa complessivo. Sviluppata inizialmente per la produzione di prototipi utilizzando fotopolimeri puri (resine), la tecnologia è stata recentemente testata per stampare sospensioni in ceramica e metallo. Attualmente, la tecnologia viene utilizzata per produrre parti 3D con materiali funzionali, come elastomeri, polimeri conduttivi, polimeri a memoria di forma, biopolimeri e materiali piezoelettrici. Questi materiali fotopolimerizzabili e sostenibili aggiungono un'altra dimensione alla parte stampata estendendo la stampa 3D alla stampa 4D. In questa tesi vengono evidenziate le novità e le caratteristiche speciali del DLP in contrasto con altre tecnologie AM. Inoltre, vengono affrontati vari aspetti del processo di stampa DLP, tra cui la preparazione del materiale, la comprensione dell'interazione tra materia leggera durante la stampa, le applicazioni e i progressi della tecnologia DLP. Lo studio si concentra anche sull'ottimizzazione della stampa per fotopolimeri puri, nonché sospensioni in ceramica e metallo. Viene proposta una semplice metodologia basata su prove preliminari di stampa dei singoli strati, per identificare le proprietà del materiale, inclusa la profondità di penetrazione e l'energia critica. Tali informazioni sono la base per disegnare una mappa di stampa utilizzando lo spessore dello strato e il tempo di esposizione come variabili indipendenti: in quanto tale, viene definito uno spazio di stampa entro il vincolo della stampabilità del materiale, garantendo così una polimerizzazione ottimale durante la stampa di oggetti tridimensionali.

(2023). Additive Manufacturing by Digital Light Processing (DLP). (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2023).

Additive Manufacturing by Digital Light Processing (DLP)

CHAUDHARY, RAJAT
2023

Abstract

Additive Manufacturing (AM) or 3D printing is a process, based on different technologies, for the design and fabrication of three-dimensional objects, an alternative to conventional subtractive manufacturing. AM enables cost-effective manufacturing especially for complex geometries, potentially with lower environmental impacts compared to conventional processes, due to design flexibility and reduced waste. These advantages have drawn the attention of various industrial sectors, for a variety of applications. Currently, several AM technologies are being used to manufacture lightweight, functional, and non-functional parts. Among them, Digital Light Processing (DLP) is one of the most recent and promising technologies for producing high-definition functional and non-functional parts. When compared to stereolithography (SLA), which is based on a laser source for voxel-by-voxel polymerization, one of the major advantages of DLP is the use of a high-resolution source, curing an entire layer with one projection at each step, thus reducing the overall printing time. Initially developed for producing prototypes using pure photopolymers (resins), the technology has been recently tested to print ceramic and metal suspensions. Currently, the technology is being used to produce 3D parts using functional materials, such as elastomers, conductive polymers, shape memory polymers, biopolymers and piezoelectric materials. These photocurable, environmentally responsive materials add up another dimension to the printed part extending 3D printing to 4D printing. In this thesis, the novelties and peculiarities of DLP are highlighted in contrast to other AM technologies. Further, it covers various aspects of the DLP printing process including material preparation, insight into light-matter interaction during printing, and applications together with the advancements in DLP technology. The study also focuses on printing optimization for pure photopolymers, as well as ceramic and metal suspensions. a simple methodology based on preliminary printing tests of single layers is proposed, to identify the material properties, including the penetration depth and critical energy. Such information is the base to draw a printing map using layer thickness and exposure time as independent variables: as such, a printing space is defined within the constraint of material printability, thus ensuring optimal polymerization during three-dimensional object printing.
ANTONINI, CARLO
Stampa 3D; DLP; Fotopolimerizzazione; Sospensione ceramica; Sospensione metallic
3D Printing; DLP; Photopolymerization; Ceramic suspension; Metal suspension
CHIM/02 - CHIMICA FISICA
English
21-mar-2023
SCIENZA E NANOTECNOLOGIA DEI MATERIALI
35
2021/2022
open
(2023). Additive Manufacturing by Digital Light Processing (DLP). (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2023).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/406815
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