Use of composite materials for different industrial applications is gaining more and more interest, mainly thanks by the high mechanical performance coupled with lightweight. Particular importance is given to Composite Reinforced Polymers, especially with thermosetting materials with short fibers. Despite the high potentialities of those materials, it is still difficult to handle their end-of-life. In this optic, Additive Manufacturing has emerged as promising solution for settle the problem, following circular economy models. Moreover, AM is gaining traction as possibility to produce big final parts with the introduction of the market of Big Area 3D printers, revolutionizing the manufacturing and opening the technology to new business models. The objective of this thesis is to create a solid foundation for the development of an innovative additive manufacturing process, LDM for big area, involving big area 3D printing of thermoset matrix composite material and recycled composite material. Important for strong basement of the system is the optimization of the parameters that define the process. As a first experimental step, the extrusion characteristics of an existing machine (Delta WASP 3MT) were studied, and an extrusion model was described and validated, fusing the printing process characteristics with the rheological characteristics of the printed material, allowing for control over the geometry and deposition speed. The curing process of thermosetting materials and thermoset matrix composites was investigated in the second experimental phase. Experiments were conducted to better understand the nature of UV LEDs, and an optical model was developed to obtain insight into the material's absorbance over time utilizing the experimental data. This data was then input into optimization software, which combined it with the geometry data to produce the optimal UV LED arrangement for the specified area. Finally, this information was used parametrically in grasshopper (Rhinoceros) by a geometry builder and then generated in FDM for mounting on the Delta WASP 3Mt. Finally, an offline system was created to facilitate subsequent phases and testing of the shell operation.
L'uso di materiali compositi per diverse applicazioni industriali sta assumendo sempre più rilevanza, soprattutto grazie alle alte prestazioni meccaniche unite alla leggerezza. Particolare importanza è data ai compositi a matrice polimerica, specialmente con materiali termoindurenti con fibre corte. Nonostante le alte potenzialità di questi materiali, è ancora difficile gestire il loro ciclo di vita. In quest'ottica, l'Additive Manufacturing è emerso come soluzione promettente per risolvere il problema, seguendo modelli di economia circolare. Inoltre, AM sta acquisendo importanza per la possibilità di produrre parti di grandi volumi con l'introduzione del mercato delle stampanti 3D Big Area, rivoluzionando la produzione e aprendo la tecnologia a nuovi modelli di business. L'obiettivo di questa tesi è quello di creare delle solide fondamenta per lo sviluppo di un innovativo processo di additive manufacturing, LDM for big area, che preveda la stampa 3d di grandi dimensioni di materiale composito a matrice termoindurente e materiale composito riciclato. Per sviluppare questo processo, è necessario ottimizzare i parametri che definiscono l'intero sistema di stampa. Come prima fase sperimentale, un macchinario già presente sul mercato (Delta WASP 3MT) è stato studiato nelle sue caratteristiche di estrusione ed è stato descritto e validato un modello di estrusione tale che le caratteristiche di processo di stampa vengano fuse con le caratteristiche reologiche del materiale stampato, per avere un controllo sulla geometria e sulla velocità di deposizione ottimale. Nella seconda fase sperimentale è stato studiato il processo di curing di materiali thermosetting e compositi a matrice termoindurente. Sono stati fatti esperimenti per comprendere la natura dei LED UV ed un modello ottico è stato dimostrato tramite i dati sperimentali, per avere maggiori informazioni sull'assorbanza del materiale nel tempo. Queste informazioni sono poi state inserite all'interno di un software di ottimizzazione, che insieme alle informazioni di geometria, ha generato una disposizione ottimale dei LED UV per la data area. In ultimo, queste informazioni sono state utilizzate da un geometry builder in modo parametrico su grasshopper (Rhinoceros), e successivamente prodotta in FDM per poter essere montata su Delta WASP 3Mt. In ultimo, un sistema offline è stato progettato per consentire futuri stadi e testing del funzionamento della calotta.
Big area liquid deposition modeling : system optimization pathway for UV curable composite materials with short fibers
Borruto, Mario Giacomo
2020/2021
Abstract
Use of composite materials for different industrial applications is gaining more and more interest, mainly thanks by the high mechanical performance coupled with lightweight. Particular importance is given to Composite Reinforced Polymers, especially with thermosetting materials with short fibers. Despite the high potentialities of those materials, it is still difficult to handle their end-of-life. In this optic, Additive Manufacturing has emerged as promising solution for settle the problem, following circular economy models. Moreover, AM is gaining traction as possibility to produce big final parts with the introduction of the market of Big Area 3D printers, revolutionizing the manufacturing and opening the technology to new business models. The objective of this thesis is to create a solid foundation for the development of an innovative additive manufacturing process, LDM for big area, involving big area 3D printing of thermoset matrix composite material and recycled composite material. Important for strong basement of the system is the optimization of the parameters that define the process. As a first experimental step, the extrusion characteristics of an existing machine (Delta WASP 3MT) were studied, and an extrusion model was described and validated, fusing the printing process characteristics with the rheological characteristics of the printed material, allowing for control over the geometry and deposition speed. The curing process of thermosetting materials and thermoset matrix composites was investigated in the second experimental phase. Experiments were conducted to better understand the nature of UV LEDs, and an optical model was developed to obtain insight into the material's absorbance over time utilizing the experimental data. This data was then input into optimization software, which combined it with the geometry data to produce the optimal UV LED arrangement for the specified area. Finally, this information was used parametrically in grasshopper (Rhinoceros) by a geometry builder and then generated in FDM for mounting on the Delta WASP 3Mt. Finally, an offline system was created to facilitate subsequent phases and testing of the shell operation.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/177489