Among the current industrial proceedings, Additive Manufacturing (AM) has been recognized as one of the most disruptive technologies in changing the paradigm of the current manufacturing industry. In particular, Wide and High Additive Manufacturing (WHAM) is emerging for the 3D printing of functional large-scale objects. Recent studies have demonstrated that the nature of these processes enables the reduction of scraps and material use with respect to the traditional manufacturing processes, paving the way towards a more sustainable production of large-volume products of thermoplastic or composites parts. However, few study still investigate the environmental impact of WHAM process and the different ways of reducing CO2 emissions. This study will deepen the sustainability in WHAM, with the main purpose of reducing the CO2 emissions related to thermoplastic material production. More in details, two paths have been followed. In the first part, material recycling was investigated. ABS filled with 20% of chopped carbon fibers was recycled and reused for a new part’s production. Here, the CO2 emissions related to material recycling and virgin material production have been calculated, as well as the associated costs with the production of the virgin material compared to its mechanical recycling process, highlighting the advantages of the reuse of the material. Moreover, a study regarding the mechanical properties of the recyclates has been conducted, underlining a decrease when adding recycled material to the mix. The second considered way to reduce material wastes consisted in reducing production scraps thanks to the prompt detection of part defect. For this purpose, in- situ thermal monitoring of the process was applied to limit the occurrence of defects. During the first experimental campaign, different cooling behaviors have been noted for the different parts of the structures, highlighting a faster cooling rate for the surface in contact with the floor. Moreover, other peculiarities of the process have been underlined, focusing the attention on the re-heating effect of the extruder for a multi-bead structure.
Tra le attuali tecnologie industriali, l’Additive Manufacturing, o Stampa 3D, si è affermata come una delle tecniche più rivoluzionarie del settore, andando a sconvolgere i paradigmi nel campo dell’industria manifatturiera. In particolare, la Wide and High Additive Manufacturing (WHAM), o stampa 3D di grande dimensione, sta guadagnando quote di mercato per la produzione di oggetti funzionali con volumi superiori al m3. Studi recenti hanno dimostrato che la natura di questi processi favorisce l’utilizzo di meno materiale e riduce gli scarti rispetto alle tecniche di manifattura tradizionale, aprendo la strada verso una produzione sostenibile di oggetti di grande dimensione in materiale termoplastico o composito. Parallelamente, sono pochi gli studi dedicati all’analisi dell’impatto ambientale per i processi WHAM con l’obiettivo di andare a ridurre le emissioni di CO2. Questo studio approfondisce il tema della sostenibilità in ambito WHAM, con l’obiettivo principale di andare a ridurre le emissioni di CO2 legate alla produzione di oggetti in materiale termoplastico. Sono stati seguiti due percorsi col fine di raggiungere questo obiettivo. Nella prima parte si è approfondito il riciclo del materiale. In particolare, si è riciclato e riutilizzato ABS caricato al 20% con fibre di carbonio corte per la produzione di nuovi oggetti. Per questo scenario, sono state calcolate le emissioni di CO2 collegate al riciclo del materiale e alla sua produzione, andando a calcolare e paragonare i relativi costi, evidenziando un vantaggio nel riutilizzo del materiale. A conclusione di questa parte, si è condotto uno studio sulle proprietà meccaniche del materiale riciclato, riscontrando una diminuzione delle proprietà alla presenza di materiale riutilizzato. Nella seconda parte si è approfondita la riduzione degli scarti di produzione grazie alla rilevazione dei difetti di stampa. A questo scopo, il monitoraggio termico in-situ è stato applicato col fine di limitare l’emergere di difetti. Durante la prima campagna sperimentale si sono evidenziati diversi comportamenti in relazione al punto considerato, osservando un raffreddamento più veloce per le regioni a contatto con il suolo. Inoltre, per strutture multi-bead, si è evidenziato un effetto di re-heating delle zone adiacenti al passaggio dell’estrusore.
Enhancing sustainability for wide and high additive manufacturing through material recycling and zero-defects production
Bellia, Andrea
2020/2021
Abstract
Among the current industrial proceedings, Additive Manufacturing (AM) has been recognized as one of the most disruptive technologies in changing the paradigm of the current manufacturing industry. In particular, Wide and High Additive Manufacturing (WHAM) is emerging for the 3D printing of functional large-scale objects. Recent studies have demonstrated that the nature of these processes enables the reduction of scraps and material use with respect to the traditional manufacturing processes, paving the way towards a more sustainable production of large-volume products of thermoplastic or composites parts. However, few study still investigate the environmental impact of WHAM process and the different ways of reducing CO2 emissions. This study will deepen the sustainability in WHAM, with the main purpose of reducing the CO2 emissions related to thermoplastic material production. More in details, two paths have been followed. In the first part, material recycling was investigated. ABS filled with 20% of chopped carbon fibers was recycled and reused for a new part’s production. Here, the CO2 emissions related to material recycling and virgin material production have been calculated, as well as the associated costs with the production of the virgin material compared to its mechanical recycling process, highlighting the advantages of the reuse of the material. Moreover, a study regarding the mechanical properties of the recyclates has been conducted, underlining a decrease when adding recycled material to the mix. The second considered way to reduce material wastes consisted in reducing production scraps thanks to the prompt detection of part defect. For this purpose, in- situ thermal monitoring of the process was applied to limit the occurrence of defects. During the first experimental campaign, different cooling behaviors have been noted for the different parts of the structures, highlighting a faster cooling rate for the surface in contact with the floor. Moreover, other peculiarities of the process have been underlined, focusing the attention on the re-heating effect of the extruder for a multi-bead structure.| File | Dimensione | Formato | |
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2022_04_Bellia.pdf
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https://hdl.handle.net/10589/188257