The volume of waste from electric and electronic equipments (WEEEs) is continuously growing, representing both a threat and an opportunity for industrialized countries. This stream constitutes a hazard for the human health and environment, but also a considerable source of value for the possibility of recovering critical materials contained in the Printed Circuit Boards (PCBs). These parts are indeed rich of gold, silver and platinum, which require automatized recycling processes to be recovered. In the last years, a new mechanical process for substituting current pyrometallurgical treatments was developed and now proposed technologies must be optimised to enhance recovery performances. One of the major barriers for effective e-waste treatment is the lack of information on scrap PCBs, that are extremely variable in structure and assembled components, and the absence of an automatic approach for analysing the products prevents the definition of an optimised treating strategy for boards. With the aim of coping with this issue, improvements for an existing automatic knowledge based system, able to forecast materials content and recognize components of waste PCBs, are presented in this thesis. Specifically, new and more robust predicting functions have been developed, allowing for more precise and reliable results. Starting from these information a smarter treating strategy for waste PCBs is proposed, comprising disassembly operations for valuable components. The new flow of information coming from the knowledge based system, allows to have tailored processes on the base of PCBs characteristics. Main novelty of this model is a new economic function here presented, which handles information collected with the vision system and returns the best disassembly level and the associated operating margin for each board. Finally, the knowledge based predicting system and the economic function have been used on an industrial case to evaluate circular economy possibilities of complex telecommunications boards.
I volumi di rifiuti generati da apparecchiature elettriche ed elettroniche (RAEE), sono in continuo aumento diventando quindi una grande sfida e oppportunità per i paesi industrializzati. Questi rifiuti hanno in sè dei rischi per l'ambiente e l'uomo, ma anche un grande valore associato alla possibilità di recuperare i materiali preziosi da essi contenuti nelle schede a circuito stampato. Queste parti sono infatti ricche di oro, argento e platino, che richiedono dei processi industriali automatici per essere recuperati. Negli ultimi anni è stato sviluppato un processo meccanico, per sostituire l'attuale trattamento pirometallurgico, che ora deve essere ottimizzato per migliorare il recupero dei materiali preziosi. Uno dei maggiori ostacoli per un efficace trattamento è la mancanza di informazioni sui prodotti in ingresso al processo, che sono estremamente varibili nella struttura e nei componenti assemblati. L'assenza di un'analisi sistematica delle schede impedisce la possibilità di definire startegie di trattamento differenziate. Con l'intento di superare questo problema vengono presentate in questa tesi le migliorie apportate ad un sistema visivo che stima la quantità di materiali contenuta e riconsce i componenti assemblati sulle schede. In particolare sono stati sviluppati nuovi modelli predittivi più robusti e più precisi rispetto ai precedenti, ottenendo delle previsioni più attendibili. Partendo dai dati ottenuti dal sistema, viene suggerita una nuova strategia per il trattamento delle schede, comprendente anche il disassemblggio di acluni componenti: il nuovo flusso di informazioni proveniente dal sistema di analisi, permette di attuare processi personalizzati per le singole schede. La principale novità di questo modello è una funzione di costo qui presentata, che grazie ai dati del sistema visivo, fornisce il livello di disassemblaggio ottimale e il margine associato a ciascuna scheda. Infine, il sistema di previsione dei materiali migliorato e la funzione economica sono stati utilizzati per valutare un caso industriale di trattamento di schede a circuito stampato.
Reuse oriented circular economy strategy of waste PCBs supported by knowledge based system
CITTERIO, PAOLO
2015/2016
Abstract
The volume of waste from electric and electronic equipments (WEEEs) is continuously growing, representing both a threat and an opportunity for industrialized countries. This stream constitutes a hazard for the human health and environment, but also a considerable source of value for the possibility of recovering critical materials contained in the Printed Circuit Boards (PCBs). These parts are indeed rich of gold, silver and platinum, which require automatized recycling processes to be recovered. In the last years, a new mechanical process for substituting current pyrometallurgical treatments was developed and now proposed technologies must be optimised to enhance recovery performances. One of the major barriers for effective e-waste treatment is the lack of information on scrap PCBs, that are extremely variable in structure and assembled components, and the absence of an automatic approach for analysing the products prevents the definition of an optimised treating strategy for boards. With the aim of coping with this issue, improvements for an existing automatic knowledge based system, able to forecast materials content and recognize components of waste PCBs, are presented in this thesis. Specifically, new and more robust predicting functions have been developed, allowing for more precise and reliable results. Starting from these information a smarter treating strategy for waste PCBs is proposed, comprising disassembly operations for valuable components. The new flow of information coming from the knowledge based system, allows to have tailored processes on the base of PCBs characteristics. Main novelty of this model is a new economic function here presented, which handles information collected with the vision system and returns the best disassembly level and the associated operating margin for each board. Finally, the knowledge based predicting system and the economic function have been used on an industrial case to evaluate circular economy possibilities of complex telecommunications boards.File | Dimensione | Formato | |
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2016_12_Citterio.pdf
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https://hdl.handle.net/10589/130561