Additive Manufacturing (AM) processes as Laser-powder Bed Fusion (L-PBF) are gaining increasing attention in industries thanks to the possibility of producing customizable products with complex geometries not otherwise feasible with traditional technologies. L-PBF exploits the main principle of AM, adding material instead of removing it, to build components layer by layer. This gives the freedom to completely re-think parts in terms of functionality or weight saving. Moreover, it becomes possible to design components in prototyping phase at lower cost and in less time, since no production equipment has to be designed or manufactured, as is the case with casting, for example. These are some of the reasons behind the growing interest for AM in sectors as the automotive one. This thesis was developed in Ferrari S.p.A where I had the opportunity to witness the steps made for L-PBF introduction inside the company, with the aim of prototypes as well as small batch production. The alloy chosen was AlSi10Mg, one of the most common aluminum alloys used in Additive Manufacturing since it represents a good compromise between mechanical characteristic and material cost. This study deals with the overall evaluation of the process from several points of view. The effects of building direction and surface condition on tensile and fatigue properties were evaluated with an in-depth analysis on defects influence. Moreover, various heat treatments (HT) were studied in order to analyze the alloy behavior and to define a HT portfolio that could cover different design requests. Obviously, being applied to a productive company, performance has to be accompanied by productivity. Hence, a large campaign was set up for process parameters optimization to reach the best compromise between mechanical properties and production time. Another aspect considered was the component working environment, since it is one of the main factors taken into account by designers during material and product validation. Therefore, an extensive study on corrosion resistance of AlSi10Mg printed parts was carried out. Several HT and surface treatment conditions were considered to evaluate the behavior in different fluids, in comparison to the one of A356 aluminum cast alloy. The aim of all this work was to study thoroughly L-PBF applied to AlSi10Mg in order to provide production solutions that could satisfy different applications. Thanks to the process knowledge and to the familiarity acquired, it was possible to draft technical specifications for both process and product controls. At the same time were defined the steps made for design and production feasibility in order to build up small batch production from a prototypal one.

I processi sotto il nome di Additive Manufacturing (AM), come il Laser Powder Bed Fusion(L-PBF), stanno acquisendo crescente interesse da parte di industrie di diversi settori grazie alla possibilità di produrre pezzi personalizzabili e di geometrie complesse, irrealizzabili con le tecnologie tradizionali. La tecnologia L-PBF sfrutta il principio alla base dell’AM, ovvero la produzione di parti aggiungendo materiale invece che rimuoverlo, per costruire componenti strato su strato. Ciò offre la libertà di ri-progettare completamente i vari prodotti da un punto di vista strettamente funzionale, con l’obiettivo, ad esempio, di una diminuzione di peso. Inoltre, offre vantaggi in fase prototipale per la riduzione di tempi e costi legati a modifiche di progetti, dal momento che non serve produrre o fornirsi di attrezzature specifiche come ad esempio accade in tecnologie tradizionali come quelle di fonderia. Questi sono alcuni dei motivi per l’aumento di interesse nel mondo dell’AM da parte di settori come quello automotive. Questa tesi è stata svolta in Ferrari S.p.A, dove ho avuto l’opportunità di osservare gli step svolti per l’introduzione e della tecnologia L-PBF, con l’obiettivo di una produzione non solo prototipale, ma anche in piccoli lotti. La lega scelta è l’AlSi10Mg, una delle leghe di alluminio più usate nell’AM grazie al rapporto tra prezzo e caratteristiche meccaniche ottenibili. Viene riportata l’analisi completa del processo svolta considerando diversi aspetti. Sono stati valutati gli effetti della direzione di stampa e della condizione superficiale sulle proprietà statiche e dinamiche, con un approfondimento sull’influenza dei difetti di stampa. Inoltre sono stati studiati e applicati diversi trattamenti termici per evidenziare gli effetti sul materiale e definire quindi un portfolio di trattamenti che potessero rispondere a diverse richieste da parte della progettazione. L’utilizzo di una nuova tecnologia in un’azienda produttiva, a prescindere dal settore, implica la necessità di ottenere non solo performance, ma anche produttività. Per questo motivo è stato impostato un importante studio per l’ottimizzazione dei parametri di stampa, con il fine di raggiungere il migliore compromesso tra proprietà meccaniche e riduzione dei tempi di produzione. Inoltre, in fase di progetto e di delibera, l’ambiente di applicazione del componente rappresenta uno dei principali fattori da considerare per la validazione del materiale e del prodotto stesso. Pertanto, è stata svolta un’estesa campagna di prove di corrosione per stabilire il comportamento di provini stampati in AlSi10Mg con diverse condizioni di trattamenti termici e superficiali a contatto con vari fluidi, a confronto con provini da fusione in lega di alluminio A356. L’obiettivo di tutto questo lavoro preliminare è stato quello di studiare approfonditamente il processo L-PBF applicato alla lega AlSi10Mg, in modo da poter fornire soluzioni produttive che potessero rispondere a diverse applicazioni. Grazie alla conoscenza della tecnologia e alla familiarità acquisita, si è giunti alla stesura di adeguate specifiche tecniche per il controllo del processo e del prodotto e alla definizione degli step necessari per passare da una fase prototipale a quella produttiva.

Introduzione all’Additive Manufacturing e in particolare alla tecnologia Laser Powder Bed Fusion per componenti automotive: dallo studio del processo alla sua applicazione industriale / Camilla Cappelletti , 2023 Mar 08. 35. ciclo, Anno Accademico 2021/2022.

Introduzione all’Additive Manufacturing e in particolare alla tecnologia Laser Powder Bed Fusion per componenti automotive: dallo studio del processo alla sua applicazione industriale

CAPPELLETTI, CAMILLA
2023

Abstract

Additive Manufacturing (AM) processes as Laser-powder Bed Fusion (L-PBF) are gaining increasing attention in industries thanks to the possibility of producing customizable products with complex geometries not otherwise feasible with traditional technologies. L-PBF exploits the main principle of AM, adding material instead of removing it, to build components layer by layer. This gives the freedom to completely re-think parts in terms of functionality or weight saving. Moreover, it becomes possible to design components in prototyping phase at lower cost and in less time, since no production equipment has to be designed or manufactured, as is the case with casting, for example. These are some of the reasons behind the growing interest for AM in sectors as the automotive one. This thesis was developed in Ferrari S.p.A where I had the opportunity to witness the steps made for L-PBF introduction inside the company, with the aim of prototypes as well as small batch production. The alloy chosen was AlSi10Mg, one of the most common aluminum alloys used in Additive Manufacturing since it represents a good compromise between mechanical characteristic and material cost. This study deals with the overall evaluation of the process from several points of view. The effects of building direction and surface condition on tensile and fatigue properties were evaluated with an in-depth analysis on defects influence. Moreover, various heat treatments (HT) were studied in order to analyze the alloy behavior and to define a HT portfolio that could cover different design requests. Obviously, being applied to a productive company, performance has to be accompanied by productivity. Hence, a large campaign was set up for process parameters optimization to reach the best compromise between mechanical properties and production time. Another aspect considered was the component working environment, since it is one of the main factors taken into account by designers during material and product validation. Therefore, an extensive study on corrosion resistance of AlSi10Mg printed parts was carried out. Several HT and surface treatment conditions were considered to evaluate the behavior in different fluids, in comparison to the one of A356 aluminum cast alloy. The aim of all this work was to study thoroughly L-PBF applied to AlSi10Mg in order to provide production solutions that could satisfy different applications. Thanks to the process knowledge and to the familiarity acquired, it was possible to draft technical specifications for both process and product controls. At the same time were defined the steps made for design and production feasibility in order to build up small batch production from a prototypal one.
Introduction of Additive Manufacturing Laser Powder Bed Fusion technology for automotive components: from process investigation to boost industrial application
8-mar-2023
BASSOLI, Elena
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1299649
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